Bio

Clinical Focus


  • Radiation Oncology
  • Spinal Tumors
  • Brain Tumors
  • Trigeminal Neuralgia
  • Radiosurgery
  • Cancer > Radiation Oncology

Academic Appointments


Honors & Awards


  • Alpha Omega Alpha, National Medical Honor Society (1999)
  • Young Investigator Award, International Stereotactic Radiosurgery Society (ISRS) (2009)
  • Henry Kaplan Memorial Prize for Teaching, Stanford Radiation Oncology (2007)
  • Phi Beta Kappa, National Honor Society (1995)
  • Malcolm A. Bagshaw Award, Stanford Radiation Oncology (2004)
  • RSNA Roentgen Resident Research Award, Radiological Society of North America (2003)
  • AACR/ASCO Methods in Clinical Cancer Research Workshop Grant, AACR/ASCO (2006)
  • Oncology Fellows Travel Grant, Annenberg Center for Health Sciences (2003)
  • Bronze Tablet University Honors, University of Illinois (1995)

Professional Education


  • Board Certification: Radiation Oncology, American Board of Radiology (2006)
  • Residency:Stanford University Medical Center (2005) CA
  • Internship:Oakwood Healthcare System (2001) MI
  • Medical Education:University of Michigan School of Medicine (2000) MI
  • B.S., University of Illinois, Cell and Structural Biology (1995)
  • M.D., Univeristy of Michigan, Medicine (2000)

Research & Scholarship

Current Research and Scholarly Interests


My clinical and research interests focus on the development of new radiation techniques involving stereotactic radiosurgery and radiotherapy for the treatment of malignant and benign tumors of the brain and spine, as well as functional disorders such as trigeminal neuralgia.

Clinical Trials


  • Avoiding the Hippocampus During Whole-Brain Radiation Therapy in Treating Patients With Brain Metastases Not Recruiting

    RATIONALE: Radiation therapy uses high energy x-rays to kill tumor cells. PURPOSE: This phase II trial is studying how well avoiding the hippocampus during whole-brain radiation therapy works in treating patients with brain metastases.

    Stanford is currently not accepting patients for this trial. For more information, please contact Jacob Wynne, (650) 723 - 8843.

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  • Memantine in Preventing Side Effects in Patients Undergoing Whole-Brain Radiation Therapy for Brain Metastases From Solid Tumors Not Recruiting

    RATIONALE: Memantine may be able to decrease side effects caused by whole-brain radiation therapy. It is not yet known if memantine is effective in preventing side effects caused by whole-brain radiation therapy. PURPOSE: This randomized phase III trial is studying memantine to see how well it works compared to a placebo in preventing side effects caused by whole-brain radiation therapy in patients with brain metastases from solid tumors.

    Stanford is currently not accepting patients for this trial. For more information, please contact Leslie Modlin, (650) 723 - 8843.

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  • A Study of Patient Reported Outcomes After Stereotactic Radiosurgical Rhizotomy for Trigeminal Neuralgia Recruiting

    The investigators know little about how patients feel following radiosurgery treatment of trigeminal neuralgia. Patient satisfaction may ultimately be one of the most important outcome measures for an individual patient; however, this has not been adequately assessed or followed. Multiple questions remain unanswered, including whether there is a correlation between patient satisfaction, the level of their current pain score, and the presence and degree of facial numbness, a possible side effect after radiosurgery. Therefore, the goal of this study is to gather this information from the patients who received radiosurgery for trigeminal neuralgia at Stanford and evaluate post-treatment patient satisfaction, the degree of facial numbness, and current pain score. This data will help the investigators understand outcomes that are important for patient satisfaction following treatment of a chronic pain syndrome.

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  • Image-Guided Radiosurgery or Stereotactic Body Radiation Therapy in Treating Patients With Localized Spine Metastasis Not Recruiting

    RATIONALE: Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. PURPOSE: This randomized phase II/III trial is studying how well image-guided radiosurgery or stereotactic body radiation therapy works and compares it to external-beam radiation therapy in treating patients with localized spine metastasis. (phase II completed as of 8-30-11)

    Stanford is currently not accepting patients for this trial. For more information, please contact Alifia Hasan, 650-725-1723.

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  • Diffusion Tensor Imaging Magnetic Resonance Imaging (DTI MRI) as a Correlate to Pain Relief and Facial Numbness in Patients Following Stereotactic Radiosurgical Rhizotomy for Trigeminal Neuralgia Recruiting

    Trigeminal neuralgia or tic douloureux is severe, often debilitating, facial pain that significantly impairs the patient's quality of life and health. Stereotactic radiosurgery has been shown to provide pain relief in majority of patients treated. However, a common side effect of radiosurgery is facial numbness. To better understand how radiosurgery can bring about pain relief and facial numbness, we are conducting a study in which brain MRI scans will be done following stereotactic radiosurgery to learn if there are any changes in the MRI scans that correlate with symptoms.

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  • Phase I Vorinostat Concurrent With Stereotactic Radiosurgery (SRS) in Brain Metastases From Non-Small Cell Lung Cancer Recruiting

    The purpose of this study is to determine the maximum tolerated dose (MTD) of vorinostat given concurrently with stereotactic radiosurgery (SRS) to treat non-small cell lung cancer (NSCLCA) brain metastases in patient with 1-4 lesions.

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  • A Study of Amifostine for Prevention of Facial Numbness in Radiosurgery Treatment of Trigeminal Neuralgia Recruiting

    Trigeminal neuralgia or tic douloureux is severe, often debilitating, facial pain that significantly impairs the patient's quality of life and health. Stereotactic radiosurgery has been shown to provide pain relief in majority of patients treated. However, a common side effect of radiosurgery is facial numbness. Our goal is to maximize pain control while minimizing side effects. To this end, the purpose of this study is to evaluate whether adding a drug, amifostine, at the time of radiosurgery will protect patients from facial numbness.

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  • Assessment of Health Related Quality of Life in Patients Treated for Rectal Cancer Not Recruiting

    Treatment of rectal cancer often consists of surgical resection of the tumor. Chemotherapy and/or radiotherapy are frequently given before or after surgery. In this study, we wish to learn if there are differences in the treatment effectiveness or in the quality of life of patients based on their type of treatment (e.g. Radiotherapy and chemotherapy before or after surgery). Information from this questionnaire collected from you and other patients may help improve the quality of life of rectal cancer patients in the future. Medical information on your tumor, treatment received, and side effects will be compiled and maintained in a database to learn more about outcomes of treatment for rectal cancer.

    Stanford is currently not accepting patients for this trial. For more information, please contact Moe Jalali, (650) 724 - 4023.

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  • Phase I/II Study of Fractionated Stereotactic Radiosurgery to Treat Large Brain Metastases Recruiting

    To determine the optimal treatment dose for large brain metastases. Brain metastases are conventionally treated with radiation to the whole brain and/or focal radiation with stereotactic radiosurgery. With conventional radiation, control rates (i.e., the ability to completely eradicate the tumor) of large brain metastases of size greater 4 cm3 are poor. By treating these tumors over 3 treatment sessions, we hope to improve the control rate and decrease side effects for patients.

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  • PI/II of Temozolomide & Hypofractionated Radiotherapy in Tx of Supratentorial Glioblastoma Multiform Recruiting

    The purpose of this study is to investigate the safety and effectiveness of a combination treatment for glioblastoma multiforme utilizing radiotherapy with the FDA approved chemotherapy drug temozolomide

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Publications

Journal Articles


  • Risk of Leptomeningeal Disease in Patients Treated With Stereotactic Radiosurgery Targeting the Postoperative Resection Cavity for Brain Metastases INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Atalar, B., Modlin, L. A., Choi, C. Y., Adler, J. R., Gibbs, I. C., Chang, S. D., Harsh, G. R., Li, G., Nagpal, S., Hanlon, A., Soltys, S. G. 2013; 87 (4): 713-718

    Abstract

    We sought to determine the risk of leptomeningeal disease (LMD) in patients treated with stereotactic radiosurgery (SRS) targeting the postsurgical resection cavity of a brain metastasis, deferring whole-brain radiation therapy (WBRT) in all patients.We retrospectively reviewed 175 brain metastasis resection cavities in 165 patients treated from 1998 to 2011 with postoperative SRS. The cumulative incidence rates, with death as a competing risk, of LMD, local failure (LF), and distant brain parenchymal failure (DF) were estimated. Variables associated with LMD were evaluated, including LF, DF, posterior fossa location, resection type (en-bloc vs piecemeal or unknown), and histology (lung, colon, breast, melanoma, gynecologic, other).With a median follow-up of 12 months (range, 1-157 months), median overall survival was 17 months. Twenty-one of 165 patients (13%) developed LMD at a median of 5 months (range, 2-33 months) following SRS. The 1-year cumulative incidence rates, with death as a competing risk, were 10% (95% confidence interval [CI], 6%-15%) for developing LF, 54% (95% CI, 46%-61%) for DF, and 11% (95% CI, 7%-17%) for LMD. On univariate analysis, only breast cancer histology (hazard ratio, 2.96) was associated with an increased risk of LMD. The 1-year cumulative incidence of LMD was 24% (95% CI, 9%-41%) for breast cancer compared to 9% (95% CI, 5%-14%) for non-breast histology (P=.004).In patients treated with SRS targeting the postoperative cavity following resection, those with breast cancer histology were at higher risk of LMD. It is unknown whether the inclusion of whole-brain irradiation or novel strategies such as preresection SRS would improve this risk or if the rate of LMD is inherently higher with breast histology.

    View details for DOI 10.1016/j.ijrobp.2013.07.034

    View details for Web of Science ID 000325763300022

    View details for PubMedID 24054875

  • Cochlea radiation dose correlates with hearing loss after stereotactic radiosurgery of vestibular schwannoma. World neurosurgery Hayden Gephart, M. G., Hansasuta, A., Balise, R. R., Choi, C., Sakamoto, G. T., Venteicher, A. S., Soltys, S. G., Gibbs, I. C., Harsh, G. R., Adler, J. R., Chang, S. D. 2013; 80 (3-4): 359-363

    Abstract

    OBJECTIVE: For multisession radiosurgery, no published data relate the volume and dose of cochlear irradiation to quantified risk of hearing loss. We conducted a retrospective, dosimetric study to evaluate the relationship between hearing loss after stereotactic radiosurgery (SRS) and the dose-volume of irradiated cochlea. METHODS: Cochlear dose data were retrospectively collected on consecutive patients who underwent SRS (18 Gy in 3 sessions) for vestibular schwanoma between 1999 and 2005 at Stanford University Hospital. Inclusion criteria included Gardner-Robertson (GR) grade I or II hearing prior to radiosurgical treatment, complete audiograms, and magnetic resonance imaging (MRI) follow-up. A cochlea dose-volume histogram was generated for each of the 94 patients who qualified for this study. RESULTS: GR grade I-II hearing posttreatment was maintained in 74% of patients (70/94). Median time to last follow-up audiogram was 2.4 years (range 0.4-8.9) and to last MRI was 3.6 years (range 0.5-9.4). Each higher level of cochlear irradiation was associated with increased risk of hearing loss. Larger cochlear volume was associated with lower risk of hearing loss. Controlling for differences in cochlear volume among subjects, each additional mm(3) of cochlea receiving 10 to 16 Gy (single session equivalent doses of 6.6-10.1 Gy3) significantly increased the odds of hearing loss by approximately 5%. CONCLUSIONS: Larger cochlear volume is associated with lower risk of hearing loss following trisession SRS for vestibular schwannoma. Controlling for this phenomenon, higher radiation dose and larger irradiated cochlear volume are significantly associated with higher risk of hearing loss. This study confirms and quantifies the risk of hearing loss following trisession SRS for vestibular schwannoma.

    View details for DOI 10.1016/j.wneu.2012.04.001

    View details for PubMedID 22484770

  • CyberKnife radiosurgery for the management of skull base and spinal chondrosarcomas. Journal of neuro-oncology Jiang, B., Veeravagu, A., Feroze, A. H., Lee, M., Harsh, G. R., Soltys, S. G., Gibbs, I. C., Adler, J. R., Chang, S. D. 2013; 114 (2): 209-218

    Abstract

    The use of CyberKnife (CK) stereotactic radiosurgery (SRS) for the management of central nervous system chondrosarcomas has not been previously reported. To evaluate outcomes of primary, recurrent, and metastatic chondrosarcomas of the skull base and spine treated with CK SRS, a retrospective observational study of 16 patients treated between 1996 and 2011 with CK SRS was performed using an IRB-approved database at Stanford University Medical Center. Twenty lesions (12 cranial, 8 spinal) across six males and ten females were analyzed. The median age at SRS was 51 years and median follow-up was 33 months. Median tumor volume was 11.0 cm(3) and median marginal dosages were 22, 24, 26, 27, and 30 Gy for one to five fractionations, respectively. Overall Kaplan-Meier survival rates were 88, 88, 80, and 66 % at 1, 3, 5, and 10 years after initial presentation. Survival rates at 1, 3, and 5 years after CK were 81, 67, and 55 %, respectively. Actuarial tumor control was 41 ± 13 % at 60 months. At 36 months follow-up, tumor control was 80 % in primary lesions, 50 % in recurrent lesions, and 0.0 % in metastatic disease (p = 0.07). Tumor control was 58 % in cranial lesions and 38 % in spinal lesions. Radiation injury was reported in one patient. CK SRS appears to be a safe adjuvant therapy and offers moderate control for primary cranial chondrosarcoma lesions. There appears to be a clinically, albeit not statistically, significant trend towards poorer outcomes in similarly treated metastatic, recurrent, and spinal chondrosarcomas (p = 0.07). Lesions not candidates for single fraction SRS may be treated with hypofractionated SRS without increased risk for radiation necrosis.

    View details for DOI 10.1007/s11060-013-1172-9

    View details for PubMedID 23748573

  • Probabilities of Radiation Myelopathy Specific to Stereotactic Body Radiation Therapy to Guide Safe Practice INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Sahgal, A., Weinberg, V., Ma, L., Chang, E., Chao, S., Muacevic, A., Gorgulho, A., Soltys, S., Gerszten, P. C., Ryu, S., Angelov, L., Gibbs, I., Wong, C. S., Larson, D. A. 2013; 85 (2): 341-347

    Abstract

    Dose-volume histogram (DVH) results for 9 cases of post spine stereotactic body radiation therapy (SBRT) radiation myelopathy (RM) are reported and compared with a cohort of 66 spine SBRT patients without RM.DVH data were centrally analyzed according to the thecal sac point maximum (Pmax) volume, 0.1- to 1-cc volumes in increments of 0.1 cc, and to the 2 cc volume. 2-Gy biologically equivalent doses (nBED) were calculated using an ?/? = 2 Gy (units = Gy(2/2)). For the 2 cohorts, the nBED means and distributions were compared using the t test and Mann-Whitney test, respectively. Significance (P<.05) was defined as concordance of both tests at each specified volume. A logistic regression model was developed to estimate the probability of RM using the dose distribution for a given volume.Significant differences in both the means and distributions at the Pmax and up to the 0.8-cc volume were observed. Concordant significance was greatest for the Pmax volume. At the Pmax volume the fit of the logistic regression model, summarized by the area under the curve, was 0.87. A risk of RM of 5% or less was observed when limiting the thecal sac Pmax volume doses to 12.4 Gy in a single fraction, 17.0 Gy in 2 fractions, 20.3 Gy in 3 fractions, 23.0 Gy in 4 fractions, and 25.3 Gy in 5 fractions.We report the first logistic regression model yielding estimates for the probability of human RM specific to SBRT.

    View details for DOI 10.1016/j.ijrobp.2012.05.007

    View details for Web of Science ID 000313642000020

    View details for PubMedID 22713832

  • Cavity Volume Dynamics After Resection of Brain Metastases and Timing of Postresection Cavity Stereotactic Radiosurgery NEUROSURGERY Atalar, B., Choi, C. Y., Harsh, G. R., Chang, S. D., Gibbs, I. C., Adler, J. R., Soltys, S. G. 2013; 72 (2): 180-185

    Abstract

    An alternative treatment option to whole-brain irradiation after surgical resection of brain metastases is resection cavity stereotactic radiosurgery (SRS).To review the dynamics of cavity volume change after surgical resection with the goal of determining the optimal timing for cavity SRS.Preresection tumor, postresection/pre-SRS cavity, and post-SRS cavity volumes were measured for 68 cavities in 63 patients treated with surgery and postresection cavity SRS. Percent differences between volumes were calculated and correlation analyses were performed to assess volume changes before and after SRS.For the majority of tumors, the postresection cavity volume was smaller than the preresection tumor volume by a median percent volume change of -29% (range, -82% to 1258%), with larger preresection tumors resulting in greater cavity shrinkage (P < .001). To determine the optimal timing for cavity SRS, we examined cavity volume dynamics by comparing the early postresection (postoperative days 0-3) and treatment planning magnetic resonance imaging scans (median time to magnetic resonance imaging, 20 days; range, 9-33 days) and found no association between the postresection day number and volume change (P = .75). The volume decrease resulting from tumor resection was offset by the addition of a 2-mm clinical target volume margin, which is our current technique.The greatest volume change occurs immediately after surgery (postoperative days 0-3) with no statistically significant volume change occurring up to 33 days after surgery for most patients. Therefore, there is no benefit of cavity shrinkage in waiting longer than the first 1 to 2 weeks to perform cavity SRS.

    View details for DOI 10.1227/NEU.0b013e31827b99f3

    View details for Web of Science ID 000313734400028

    View details for PubMedID 23149969

  • What Is the Optimal Treatment of Large Brain Metastases? An Argument for a Multidisciplinary Approach INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Choi, C. Y., Chang, S. D., Gibbs, I. C., Adler, J. R., Harsh, G. R., Atalar, B., Lieberson, R. E., Soltys, S. G. 2012; 84 (3): 688-693

    Abstract

    Single-modality treatment of large brain metastases (>2 cm) with whole-brain irradiation, stereotactic radiosurgery (SRS) alone, or surgery alone is not effective, with local failure (LF) rates of 50% to 90%. Our goal was to improve local control (LC) by using multimodality therapy of surgery and adjuvant SRS targeting the resection cavity.We retrospectively evaluated 97 patients with brain metastases >2 cm in diameter treated with surgery and cavity SRS. Local and distant brain failure (DF) rates were analyzed with competing risk analysis, with death as a competing risk. The overall survival rate was calculated by the Kaplain-Meier product-limit method.The median imaging follow-up duration for all patients was 10 months (range, 1-80 months). The 12-month cumulative incidence rates of LF, with death as a competing risk, were 9.3% (95% confidence interval [CI], 4.5%-16.1%), and the median time to LF was 6 months (range, 3-17 months). The 12-month cumulative incidence rate of DF, with death as a competing risk, was 53% (95% CI, 43%-63%). The median survival time for all patients was 15.6 months. The median survival times for recursive partitioning analysis classes 1, 2, and 3 were 33.8, 13.7, and 9.0 months, respectively (p = 0.022). On multivariate analysis, Karnofsky Performance Status (?80 vs. <80; hazard ratio 0.54; 95% CI 0.31-0.94; p = 0.029) and maximum preoperative tumor diameter (hazard ratio 1.41; 95% CI 1.08-1.85; p = 0.013) were associated with survival. Five patients (5%) required intervention for Common Terminology Criteria for Adverse Events v4.02 grade 2 and 3 toxicity.Surgery and adjuvant resection cavity SRS yields excellent LC of large brain metastases. Compared with other multimodality treatment options, this approach allows patients to avoid or delay whole-brain irradiation without compromising LC.

    View details for DOI 10.1016/j.ijrobp.2012.01.028

    View details for Web of Science ID 000309560600051

    View details for PubMedID 22445007

  • Stereotactic Radiosurgery of the Postoperative Resection Cavity for Brain Metastases: Prospective Evaluation of Target Margin on Tumor Control INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Choi, C. Y., Chang, S. D., Gibbs, I. C., Adler, J. R., Harsh, G. R., Lieberson, R. E., Soltys, S. G. 2012; 84 (2): 336-342

    Abstract

    Given the neurocognitive toxicity associated with whole-brain irradiation (WBRT), approaches to defer or avoid WBRT after surgical resection of brain metastases are desirable. Our initial experience with stereotactic radiosurgery (SRS) targeting the resection cavity showed promising results. We examined the outcomes of postoperative resection cavity SRS to determine the effect of adding a 2-mm margin around the resection cavity on local failure (LF) and toxicity.We retrospectively evaluated 120 cavities in 112 patients treated from 1998-2009. Factors associated with LF and distant brain failure (DF) were analyzed using competing risks analysis, with death as a competing risk. The overall survival (OS) rate was calculated by the Kaplan-Meier product-limit method; variables associated with OS were evaluated using the Cox proportional hazards and log rank tests.The 12-month cumulative incidence rates of LF and DF, with death as a competing risk, were 9.5% and 54%, respectively. On univariate analysis, expansion of the cavity with a 2-mm margin was associated with decreased LF; the 12-month cumulative incidence rates of LF with and without margin were 3% and 16%, respectively (P=.042). The 12-month toxicity rates with and without margin were 3% and 8%, respectively (P=.27). On multivariate analysis, melanoma histology (P=.038) and number of brain metastases (P=.0097) were associated with higher DF. The median OS time was 17 months (range, 2-114 months), with a 12-month OS rate of 62%. Overall, WBRT was avoided in 72% of the patients.Adjuvant SRS targeting the resection cavity of brain metastases results in excellent local control and allows WBRT to be avoided in a majority of patients. A 2-mm margin around the resection cavity improved local control without increasing toxicity compared with our prior technique with no margin.

    View details for DOI 10.1016/j.ijrobp.2011.12.009

    View details for Web of Science ID 000308062700035

    View details for PubMedID 22652105

  • CyberKnife stereotactic radiosurgery for the treatment of intramedullary spinal cord metastases JOURNAL OF CLINICAL NEUROSCIENCE Veeravagu, A., Lieberson, R. E., Mener, A., Chen, Y., Soltys, S. G., Gibbs, I. C., Adler, J. R., Tian, A. G., Chang, S. D. 2012; 19 (9): 1273-1277

    Abstract

    Spinal cord intramedullary metastases are uncommon and treatment options are limited. We reviewed our experience treating these lesions with radiosurgery to assess safety and efficacy, and to define preliminary treatment recommendations. With Institutional Review Board approval, we identified nine patients with 11 metastases treated with radiosurgery at Stanford University Hospital, between 2000 and 2010. We also reviewed all available published series discussing the treatment of spinal cord metastases. Our patients ranged in age from 33 years to 77 years (median 63 years) and included seven women and two men. Tumors ranged in size from 0.12 cm(3) to 6.4 cm(3) (median 0.48 cm(3)). Five were from breast cancer, two were non-small cell lung cancers, one was a cystic adenocarcinoma, and one was from an epithelioid hemangioepithelioma. All patients had neurologic deficits and multiple other metastases. We delivered 14 Gy to 27 Gy (median 21 Gy) in one to five (median 3) fractions. Complete follow-up was available for all nine patients. One patient remains alive 14 months after therapy. Of the eight deceased patients, survival ranged from one month and two days to nine months and six days (median four months and four days). There were no local recurrences or worsened neurological deficits. To our knowledge this is the largest reported series of spinal cord intramedullary metastases treated with radiosurgery. Survival was poor due to systemic disease, but radiosurgery appears to be safe and prevented local recurrences. With fewer sessions than conventional radiation and less morbidity than surgery, we feel radiosurgery is appropriate for the palliative treatment of these lesions.

    View details for DOI 10.1016/j.jocn.2012.02.002

    View details for Web of Science ID 000308730900014

    View details for PubMedID 22766103

  • Esophageal tolerance to high-dose stereotactic ablative radiotherapy DISEASES OF THE ESOPHAGUS Abelson, J. A., Murphy, J. D., Loo, B. W., Chang, D. T., Daly, M. E., Wiegner, E. A., Hancock, S., Chang, S. D., Le, Q., Soltys, S. G., Gibbs, I. C. 2012; 25 (7): 623-629

    Abstract

    Dose-volume parameters are needed to guide the safe administration of stereotactic ablative radiotherapy (SABR). We report on esophageal tolerance to high-dose hypofractionated radiation in patients treated with SABR. Thirty-one patients with spine or lung tumors received single- or multiple-fraction SABR to targets less than 1 cm from the esophagus. End points evaluated include D(5cc) (minimum dose in Gy to 5 cm(3) of the esophagus receiving the highest dose), D(2cc) , D(1cc) , and D(max) (maximum dose to 0.01 cm(3) ). Multiple-fraction treatments were correlated using the linear quadratic and linear quadratic-linear/universal survival models. Three esophageal toxicity events occurred, including esophagitis (grade 2), tracheoesophageal fistula (grade 4-5), and esophageal perforation (grade 4-5). Chemotherapy was a cofactor in the high-grade events. The median time to development of esophageal toxicity was 4.1 months (range 0.6-6.1 months). Two of the three events occurred below a published D(5cc) threshold, all three were below a D(2cc) threshold, and one was below a D(max) threshold. We report a dosimetric analysis of incidental dose to the esophagus from SABR. High-dose hypofractionated radiotherapy led to a number of high-grade esophageal adverse events, suggesting that conservative parameters to protect the esophagus are necessary when SABR is used, especially in the setting of chemotherapy or prior radiotherapy.

    View details for DOI 10.1111/j.1442-2050.2011.01295.x

    View details for Web of Science ID 000308712300008

    View details for PubMedID 22168251

  • International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Cox, B. W., Spratt, D. E., Lovelock, M., Bilsky, M. H., Lis, E., Ryu, S., Sheehan, J., Gerszten, P. C., Chang, E., Gibbs, I., Soltys, S., Sahgal, A., Deasy, J., Flickinger, J., Quader, M., Mindea, S., Yamada, Y. 2012; 83 (5): E597-E605

    Abstract

    Spinal stereotactic radiosurgery (SRS) is increasingly used to manage spinal metastases. However, target volume definition varies considerably and no consensus target volume guidelines exist. This study proposes consensus target volume definitions using common scenarios in metastatic spine radiosurgery.Seven radiation oncologists and 3 neurological surgeons with spinal radiosurgery expertise independently contoured target and critical normal structures for 10 cases representing common scenarios in metastatic spine radiosurgery. Each set of volumes was imported into the Computational Environment for Radiotherapy Research. Quantitative analysis was performed using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE) with kappa statistics calculating agreement between physicians. Optimized confidence level consensus contours were identified using histogram agreement analysis and characterized to create target volume definition guidelines.Mean STAPLE agreement sensitivity and specificity was 0.76 (range, 0.67-0.84) and 0.97 (range, 0.94-0.99), respectively, for gross tumor volume (GTV) and 0.79 (range, 0.66-0.91) and 0.96 (range, 0.92-0.98), respectively, for clinical target volume (CTV). Mean kappa agreement was 0.65 (range, 0.54-0.79) for GTV and 0.64 (range, 0.54-0.82) for CTV (P<.01 for GTV and CTV in all cases). STAPLE histogram agreement analysis identified optimal consensus contours (80% confidence limit). Consensus recommendations include that the CTV should include abnormal marrow signal suspicious for microscopic invasion and an adjacent normal bony expansion to account for subclinical tumor spread in the marrow space. No epidural CTV expansion is recommended without epidural disease, and circumferential CTVs encircling the cord should be used only when the vertebral body, bilateral pedicles/lamina, and spinous process are all involved or there is extensive metastatic disease along the circumference of the epidural space.This report provides consensus guidelines for target volume definition for spinal metastases receiving upfront SRS in common clinical situations.

    View details for DOI 10.1016/j.ijrobp.2012.03.009

    View details for Web of Science ID 000306128100006

    View details for PubMedID 22608954

  • Management of intracranial and extracranial chordomas with CyberKnife stereotactic radiosurgery JOURNAL OF CLINICAL NEUROSCIENCE Jiang, B., Veeravagu, A., Lee, M., Harsh, G. R., Lieberson, R. E., Bhatti, I., Soltys, S. G., Gibbs, I. C., Adler, J. R., Chang, S. D. 2012; 19 (8): 1101-1106

    Abstract

    Chordomas are rare, malignant bone tumors of the axial skeleton, occurring particularly at the cranial base or in the sacro-coccygeal region. Although slow growing, chordomas are locally aggressive and challenging to treat. We evaluate the outcomes of skull base and spinal chordomas in 20 patients treated with CyberKnife (CK) stereotactic radiosurgery (SRS) (Accuray, Sunnyvale, CA, USA) between 1994 and 2010 at Stanford Hospital. There were 12 males and eight females (10-78 years; median age: 51.5 years). Eleven patients received CK as primary adjuvant therapy and nine patients received CK for multiple recurrences. The average tumor volume treated was 16.1cm(3) (2.4-45.9 cm(3)), with a mean marginal dose of 32.5 Gy (18-50 Gy). Median follow-up was 34 months (2-131 months). Overall, tumor control was achieved in 11 patients (55%), with eight patients showing tumor size reduction. However, nine patients showed progression and eventually succumbed to the disease (mean time from CK to death was 26.3 months). Of the patients treated with CK as the primary adjuvant therapy, 81.8% had stable or improved outcomes. Only 28.6% of those treated with CK for recurrences had stable or improved outcomes. The overall Kaplan-Meyer survival at five years from the first CK treatment was 52.5%. Moderate tumor control rates can be achieved with few complications with CK SRS. Poor control is associated with complex multiple surgical resections, long delay between initial resection and CK therapy, and recurrently aggressive disease uncontrolled by prior radiation.

    View details for DOI 10.1016/j.jocn.2012.01.005

    View details for Web of Science ID 000306500400009

    View details for PubMedID 22727205

  • A Planned Neck Dissection Is Not Necessary in All Patients With N2-3 Head-and-Neck Cancer After Sequential Chemoradiotherapy INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Soltys, S. G., Choi, C. Y., Fee, W. E., Pinto, H. A., Le, Q. 2012; 83 (3): 994-999

    Abstract

    To assess the role of a planned neck dissection (PND) after sequential chemoradiotherapy for patients with head-and-neck cancer with N2-N3 nodal disease.We reviewed 90 patients with N2-N3 head-and-neck squamous cell carcinoma treated between 1991 and 2001 on two sequential chemoradiotherapy protocols. All patients received induction and concurrent chemotherapy with cisplatin and 5-fluorocuracil, with or without tirapazamine. Patients with less than a clinical complete response (cCR) in the neck proceeded to a PND after chemoradiation. The primary endpoint was nodal response. Clinical outcomes and patterns of failure were analyzed.The median follow-up durations for living and all patients were 8.3 years (range, 1.5-16.3 year) and 5.4 years (range, 0.6-16.3 years), respectively. Of the 48 patients with nodal cCR whose necks were observed, 5 patients had neck failures as a component of their recurrence [neck and primary (n = 2); neck, primary, and distant (n = 1); neck only (n = 1); neck and distant (n = 1)]. Therefore, PND may have benefited only 2 patients (4%) [neck only failure (n = 1); neck and distant failure (n = 1)]. The pathologic complete response (pCR) rate for those with a clinical partial response (cPR) undergoing PND (n = 30) was 53%. The 5-year neck control rates after cCR, cPR?pCR, and cPR?pPR were 90%, 93%, and 78%, respectively (p = 0.36). The 5-year disease-free survival rates for the cCR, cPR?pCR, and cPR?pPR groups were 53%, 75%, and 42%, respectively (p = 0.04).In our series, patients with N2-N3 neck disease achieving a cCR in the neck, PND would have benefited only 4% and, therefore, is not recommended. Patients with a cPR should be treated with PND. Residual tumor in the PND specimens was associated with poor outcomes; therefore, aggressive therapy is recommended. Studies using novel imaging modalities are needed to better assess treatment response.

    View details for DOI 10.1016/j.ijrobp.2011.07.042

    View details for Web of Science ID 000305256000055

    View details for PubMedID 22137026

  • Stereotactic Radiosurgery as the Primary Treatment for New and Recurrent Paragangliomas: Is Open Surgical Resection Still the Treatment of Choice? WORLD NEUROSURGERY Lieberson, R. E., Adler, J. R., Soltys, S. G., Choi, C., Gibbs, I. C., Chang, S. D. 2012; 77 (5-6): 745-761

    Abstract

    Paragangliomas (PGs) or glomus tumors are rare, and publications comparing treatment alternatives are few. We sought to analyze our experience with stereotactic radiosurgery (SRS), review the literature, and develop treatment guidelines.We retrospectively examined the outcomes of 41 PGs in 36 patients treated with SRS at Stanford. Our data from medical records, telephone interviews, and imaging studies were combined with previously reported SRS data and compared to results following other treatments.With a median clinical follow-up of 4.8 years (3.9 years radiographic), local control was 100%. Complications included increase in preexistent vertigo in one patient and transient cranial neuropathies in two patients. Published surgical series describe a lower local control rate as well as more frequent and severe complications. Published radiation therapy (RT) series document a slightly lower local control rate than SRS, but SRS can be delivered more quickly and conveniently. Open surgery and other combinations of treatments appear to be required for several subpopulations of PG patients.We feel that SRS should be the primary treatment for most new and recurrent PGs. Even some very large PGs are appropriate for SRS. RT remains an appropriate option in some centers, especially those where SRS is not available. PGs occurring in the youngest patients, catecholamine secreting PGs, and PGs causing rapidly progressing neurologic deficits may be more appropriate for open resection. Metastatic PGs may benefit from combinations of chemotherapy and SRS or RT. Treatment guidelines are proposed.

    View details for DOI 10.1016/j.wneu.2011.03.026

    View details for Web of Science ID 000307523800038

    View details for PubMedID 22818172

  • NORMAL TISSUE COMPLICATION PROBABILITY ESTIMATION BY THE LYMAN-KUTCHER-BURMAN METHOD DOES NOT ACCURATELY PREDICT SPINAL CORD TOLERANCE TO STEREOTACTIC RADIOSURGERY INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Daly, M. E., Luxton, G., Choi, C. Y., Gibbs, I. C., Chang, S. D., Adler, J. R., Soltys, S. G. 2012; 82 (5): 2025-2032

    Abstract

    To determine whether normal tissue complication probability (NTCP) analyses of the human spinal cord by use of the Lyman-Kutcher-Burman (LKB) model, supplemented by linear-quadratic modeling to account for the effect of fractionation, predict the risk of myelopathy from stereotactic radiosurgery (SRS).From November 2001 to July 2008, 24 spinal hemangioblastomas in 17 patients were treated with SRS. Of the tumors, 17 received 1 fraction with a median dose of 20 Gy (range, 18-30 Gy) and 7 received 20 to 25 Gy in 2 or 3 sessions, with cord maximum doses of 22.7 Gy (range, 17.8-30.9 Gy) and 22.0 Gy (range, 20.2-26.6 Gy), respectively. By use of conventional values for ?/?, volume parameter n, 50% complication probability dose TD(50), and inverse slope parameter m, a computationally simplified implementation of the LKB model was used to calculate the biologically equivalent uniform dose and NTCP for each treatment. Exploratory calculations were performed with alternate values of ?/? and n.In this study 1 case (4%) of myelopathy occurred. The LKB model using radiobiological parameters from Emami and the logistic model with parameters from Schultheiss overestimated complication rates, predicting 13 complications (54%) and 18 complications (75%), respectively. An increase in the volume parameter (n), to assume greater parallel organization, improved the predictive value of the models. Maximum-likelihood LKB fitting of ?/? and n yielded better predictions (0.7 complications), with n = 0.023 and ?/? = 17.8 Gy.The spinal cord tolerance to the dosimetry of SRS is higher than predicted by the LKB model using any set of accepted parameters. Only a high ?/? value in the LKB model and only a large volume effect in the logistic model with Schultheiss data could explain the low number of complications observed. This finding emphasizes that radiobiological models traditionally used to estimate spinal cord NTCP may not apply to the dosimetry of SRS. Further research with additional NTCP models is needed.

    View details for DOI 10.1016/j.ijrobp.2011.03.004

    View details for Web of Science ID 000301891300082

    View details for PubMedID 21531516

  • Trigeminal neuralgia treatment dosimetry of the Cyberknife MEDICAL DOSIMETRY Ho, A., Lo, A. T., Dieterich, S., Soltys, S. G., Gibbs, I. C., Chang, S. G., Adler, J. R. 2012; 37 (1): 42-46

    Abstract

    There are 2 Cyberknife units at Stanford University. The robot of 1 Cyberknife is positioned on the patient's right, whereas the second is on the patient's left. The present study examines whether there is any difference in dosimetry when we are treating patients with trigeminal neuralgia when the target is on the right side or the left side of the patient. In addition, we also study whether Monte Carlo dose calculation has any effect on the dosimetry. We concluded that the clinical and dosimetric outcomes of CyberKnife treatment for trigeminal neuralgia are independent of the robot position. Monte Carlo calculation algorithm may be useful in deriving the dose necessary for trigeminal neuralgia treatments.

    View details for DOI 10.1016/j.meddos.2010.12.012

    View details for Web of Science ID 000301035000009

    View details for PubMedID 21723113

  • Impact of Dose Hot Spots on Spinal Cord Tolerance Following Stereotactic Body Radiotherapy: A Generalized Biological Effective Dose Analysis TECHNOLOGY IN CANCER RESEARCH & TREATMENT Sahgal, A., Ma, L., Fowler, J., Weinberg, V., Gibbs, I., Gerszten, P. C., Ryu, S., Soltys, S., Chang, E., Wong, C. S., Larson, D. A. 2012; 11 (1): 35-40

    Abstract

    The purpose of this study was to investigate the effects of high-dose inhomogeneous irradiation to small volumes of spinal cord with a new generalized biological effective dose (gBED) analysis for spine stereotactic body radiotherapy (SBRT). The gBED was applied to spinal cord dosimetric data (contoured per the thecal sac) at specified volumes for a cohort of five patients with radiation-induced myelopathy (RM) and compared to nineteen patients without RM post-SBRT. The spinal cord gBED was calculated and normalized to a conventional 2-Gy equivalent dose fraction scheme (?/? = 2 Gy for late toxicity). Differences between the conventional BED and those gBED calculations by accounting for small-volume dosing within the spinal cord was observed. Statistically significant differences in the mean gBED between the RM group and the non-RM group was observed both at the maximum point volume (gBED of 66 Gy vs. 37 Gy (p = 0.01), respectively) and at the 0.1 cm(3) volume (gBED of 53 Gy vs. 28 Gy (p = 0.01), respectively). No significant difference at the 0.1 cm(3) volume was observed based on the mean BED comparisons. No significant differences were observed at the larger 1 cm(3), 2 cm(3) or 5 cm(3) volumes for either BED or gBED comparisons. We conclude that differences in dose hot spots characteristics within small inhomogenously irradiated volumes of spinal cord can affect spinal cord tolerance following SBRT treatments.

    View details for Web of Science ID 000298867500005

    View details for PubMedID 22181329

  • REIRRADIATION HUMAN SPINAL CORD TOLERANCE FOR STEREOTACTIC BODY RADIOTHERAPY INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Sahgal, A., Ma, L., Weinberg, V., Gibbs, I. C., Chao, S., Chang, U., Werner-Wasik, M., Angelov, L., Chang, E. L., Sohn, M., Soltys, S. G., Letourneau, D., Ryu, S., Gerszten, P. C., Fowler, J., Wong, C. S., Larson, D. A. 2012; 82 (1): 107-116

    Abstract

    We reviewed the treatment for patients with spine metastases who initially received conventional external beam radiation (EBRT) and were reirradiated with 1-5 fractions of stereotactic body radiotherapy (SBRT) who did or did not subsequently develop radiation myelopathy (RM).Spinal cord dose-volume histograms (DVHs) for 5 RM patients (5 spinal segments) and 14 no-RM patients (16 spine segments) were based on thecal sac contours at retreatment. Dose to a point within the thecal sac that receives the maximum dose (P(max)), and doses to 0.1-, 1.0-, and 2.0-cc volumes within the thecal sac were reviewed. The biologically effective doses (BED) using ?/? = 2 Gy for late spinal cord toxicity were calculated and normalized to a 2-Gy equivalent dose (nBED = Gy(2/2)).The initial conventional radiotherapy nBED ranged from ~30 to 50 Gy(2/2) (median ~40 Gy(2/2)). The SBRT reirradiation thecal sac mean P(max) nBED in the no-RM group was 20.0 Gy(2/2) (95% confidence interval [CI], 10.8-29.2), which was significantly lower than the corresponding 67.4 Gy(2/2) (95% CI, 51.0-83.9) in the RM group. The mean total P(max) nBED in the no-RM group was 62.3 Gy(2/2) (95% CI, 50.3-74.3), which was significantly lower than the corresponding 105.8 Gy(2/2) (95% CI, 84.3-127.4) in the RM group. The fraction of the total P(max) nBED accounted for by the SBRT P(max) nBED for the RM patients ranged from 0.54 to 0.78 and that for the no-RM patients ranged from 0.04 to 0.53.SBRT given at least 5 months after conventional palliative radiotherapy with a reirradiation thecal sac P(max) nBED of 20-25 Gy(2/2) appears to be safe provided the total P(max) nBED does not exceed approximately 70 Gy(2/2), and the SBRT thecal sac P(max) nBED comprises no more than approximately 50% of the total nBED.

    View details for DOI 10.1016/j.ijrobp.2010.08.021

    View details for Web of Science ID 000298526100018

    View details for PubMedID 20951503

  • Multisession Stereotactic Radiosurgery for Vestibular Schwannomas: Single-Institution Experience With 383 Cases NEUROSURGERY Hansasuta, A., Choi, C. Y., Gibbs, I. C., Soltys, S. G., Tse, V. C., Lieberson, R. E., Hayden, M. G., Sakamoto, G. T., Harsh, G. R., Adler, J. R., Chang, S. D. 2011; 69 (6): 1200-1209

    Abstract

    Single-session stereotactic radiosurgery (SRS) treatment of vestibular schwannomas results in excellent tumor control. It is not known whether functional outcomes can be improved by fractionating the treatment over multiple sessions.To examine tumor control and complication rates after multisession SRS.Three hundred eighty-three patients treated with SRS from 1999 to 2007 at Stanford University Medical Center were retrospectively reviewed. Ninety percent were treated with 18 Gy in 3 sessions, targeting a median tumor volume of 1.1 cm3 (range, 0.02-19.8 cm3).During a median follow-up duration of 3.6 years (range, 1-10 years), 10 tumors required additional treatment, resulting in 3- and 5-year Kaplan-Meier tumor control rates of 99% and 96%, respectively. Five-year tumor control rate was 98% for tumors < 3.4 cm3. Neurofibromatosis type 2-associated tumors were associated with worse tumor control (P = .02). Of the 200 evaluable patients with pre-SRS serviceable hearing (Gardner-Robertson grade 1 and 2), the crude rate of serviceable hearing preservation was 76%. Smaller tumor volume was associated with hearing preservation (P = .001). There was no case of post-SRS facial weakness. Eight patients (2%) developed trigeminal dysfunction, half of which was transient.Multisession SRS treatment of vestibular schwannomas results in an excellent rate of tumor control. The hearing, trigeminal nerve, and facial nerve function preservation rates reported here are promising.

    View details for DOI 10.1227/NEU.0b013e318222e451

    View details for Web of Science ID 000296794500024

    View details for PubMedID 21558974

  • Stereotactic Radiosurgery Yields Long-term Control for Benign Intradural, Extramedullary Spinal Tumors NEUROSURGERY Sachdev, S., Dodd, R. L., Chang, S. D., Soltys, S. G., Adler, J. R., Luxton, G., Choi, C. Y., Tupper, L., Gibbs, I. C. 2011; 69 (3): 533-539

    Abstract

    The role of stereotactic radiosurgery in the treatment of benign intracranial lesions is well established. Although a growing body of evidence supports its role in the treatment of malignant spinal lesions, a much less extensive dataset exists for treatment of benign spinal tumors.To examine the safety and efficacy of stereotactic radiosurgery for treatment of benign, intradural extramedullary spinal tumors.From 1999 to 2008, 87 patients with 103 benign intradural extramedullary spinal tumors (32 meningiomas, 24 neurofibromas, and 47 schwannomas) were treated with stereotactic radiosurgery at Stanford University Medical Center. Forty-three males and 44 females had a median age of 53 years (range, 12-86). Twenty-five patients had neurofibromatosis. Treatment was delivered in 1 to 5 sessions (median, 2) with a mean prescription dose of 19.4 Gy (range, 14-30 Gy) to an average tumor volume of 5.24 cm (range, 0.049-54.52 cm).After a mean radiographic follow-up period of 33 months (range, 6-87), including 21 lesions followed for ? 48 months, 59% were stable, 40% decreased in size, and a single tumor (1%) increased in size. Clinically, 91%, 67%, and 86% of meningiomas, neurofibromas, and schwannomas, respectively, were symptomatically stable to improved at last follow-up. One patient with a meningioma developed a new, transient myelopathy at 9 months, although the tumor was smaller at last follow-up.As a viable alternative to microsurgical resection, stereotactic radiosurgery provides safe and efficacious long-term control of benign intradural, extramedullary spinal tumors with a low rate of complication.

    View details for DOI 10.1227/NEU.0b013e318218db23

    View details for Web of Science ID 000293586200003

    View details for PubMedID 21832967

  • CyberKnife Stereotactic Radiosurgery for Recurrent, Metastatic, and Residual Hemangiopericytomas JOURNAL OF HEMATOLOGY & ONCOLOGY Veeravagu, A., Jiang, B., Patil, C. G., Lee, M., Soltys, S. G., Gibbs, I. C., Chang, S. D. 2011; 4

    Abstract

    Hemangiopericytoma is a rare and aggressive meningeal tumor. Although surgical resection is the standard treatment, hemangiopericytomas often recur with high incidences of metastasis. The purpose of this study was to evaluate the role of CyberKnife stereotactic radiosurgery (CK) in the management of recurrent, metastatic, and residual hemangiopericytomas.In a review of the Stanford radiosurgery database between 2002 and 2009, the authors found 14 patients who underwent CK therapy for recurrent, metastatic, and residual hemangiopericytomas. A total of 24 tumors were treated and the median patient age was 52 years (range 29-70 years) at the time of initial CK therapy. The median follow-up period was 37 months (10-73 months) and all patients had been previously treated with surgical resection. Mean tumor volume was 9.16 cm3 and the mean marginal and maximum radiosurgical doses to the tumors were 21.2 Gy and 26.8 Gy, respectively.Of the 24 tumors treated, 22 have clinical follow-up data at this time. Of those 22 tumors, 12 decreased in size (54.5%), 6 remained unchanged (27.3%), and 4 showed recurrence (18.2%) after CK therapy. Progression-free survival rate was 95%, 71.5%, and 71.5% at 1, 3, and 5 years after multiple CK treatments. The 5-year survival rate after CK was 81%.CK is an effective and safe management option for hemangiopericytomas. The current series demonstrates a tumor control of 81.8%. Other institutions have demonstrated similar outcomes with stereotactic radiosurgery, with tumor control ranging from 46.4% to 100%.

    View details for DOI 10.1186/1756-8722-4-26

    View details for Web of Science ID 000291817100001

    View details for PubMedID 21645367

  • Stereotactic Radiosurgery of Cranial Nonvestibular Schwannomas: Results of Single- and Multisession Radiosurgery NEUROSURGERY Choi, C. Y., Soltys, S. G., Gibbs, I. C., Harsh, G. R., Sakamoto, G. T., Patel, D. A., Lieberson, R. E., Chang, S. D., Adler, J. R. 2011; 68 (5): 1200-1208

    Abstract

    Surgical resection of nonvestibular cranial schwannomas carries a considerable risk of postoperative complications. Stereotactic radiosurgery (SRS) offers a non-invasive treatment alternative. The efficacy and safety of multi-session SRS of nonvestibular cranial schwannomas has not been well studied.To analyze the results of single- and multi-session SRS of nonvestibular cranial schwannomas.From 2001 to 2007, 42 lesions in 40 patients were treated with SRS at Stanford University Medical Center, targeting schwannomas of cranial nerves IV (n = 1), V (n = 18), VII (n = 6), X (n = 5), XII (n = 2), jugular foramen (n = 8), and cavernous sinus (n = 2). SRS was delivered to a median marginal dose of 18 Gy (range, 15-33 Gy) in 1 to 3 sessions, targeting a median tumor volume of 3.2 cm (range, 0.1-23.7 cm). The median doses for treatments in 1 (n = 18), 2 (n = 9), and 3 (n = 15) sessions were 17.5, 20, and 18 Gy, respectively.With a median follow-up of 29 months (range, 6-84 months), tumor control was achieved in 41 of the 42 lesions. Eighteen of 42 lesions (43%) decreased in size; 23 tumors (55%) remained stable. There were 2 cases of new or worsening cranial nerve deficits in patients treated in single session; no patient treated with multi-session SRS experienced any cranial nerve toxicity (P = 0.18).SRS of nonvestibular cranial schwannomas provides excellent tumor control with minimal risk of complications. There was a trend towards decreased complications with multi-session SRS.

    View details for DOI 10.1227/NEU.0b013e31820c0474

    View details for Web of Science ID 000289230300033

    View details for PubMedID 21273918

  • TOLERANCE OF THE SPINAL CORD TO STEREOTACTIC RADIOSURGERY: INSIGHTS FROM HEMANGIOBLASTOMAS INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Daly, M. E., Choi, C. Y., Gibbs, I. C., Adler, J. R., Chang, S. D., Lieberson, R. E., Soltys, S. G. 2011; 80 (1): 213-220

    Abstract

    To evaluate spinal cord dose-volume effects, we present a retrospective review of stereotactic radiosurgery (SRS) treatments for spinal cord hemangioblastomas.From November 2001 to July 2008, 27 spinal hemangioblastomas were treated in 19 patients with SRS. Seventeen tumors received a single fraction with a median dose of 20 Gy (range, 18-30 Gy). Ten lesions were treated using 18-25 Gy in two to three sessions. Cord volumes receiving 8, 10, 12, 14, 16, 18, 20, 22, and 24 Gy and dose to 10, 100, 250, 500, 1000, and 2000 mm(3) of cord were determined. Multisession treatments were converted to single-fraction biologically effective dose (SFBED).Single-fraction median cord D(max) was 22.7 Gy (range, 17.8-30.9 Gy). Median V10 was 454 mm(3) (range, 226-3543 mm(3)). Median dose to 500 mm(3) cord was 9.5 Gy (range, 5.3-22.5 Gy). Fractionated median SFBED(3) cord D(max) was 14.1 Gy(3) (range, 12.3-19.4 Gy(3)). Potential toxicities included a Grade 2 unilateral foot drop 5 months after SRS and 2 cases of Grade 1 sensory deficits. The actuarial 3-year local tumor control estimate was 86%.Despite exceeding commonly cited spinal cord dose constraints, SRS for spinal hemangioblastomas is safe and effective. Consistent with animal experiments, these data support a partial-volume tolerance model for the human spinal cord. Because irradiated cord volumes were generally small, application of these data to other clinical scenarios should be made cautiously. Further prospective studies of spinal radiosurgery are needed.

    View details for DOI 10.1016/j.ijrobp.2010.01.040

    View details for Web of Science ID 000290006300031

    View details for PubMedID 21481724

  • Cyberknife Stereotactic Radiosurgery for Treatment of Atypical (Who Grade II) Cranial Meningiomas NEUROSURGERY Choi, C. Y., Soltys, S. G., Gibbs, I. C., Harsh, G. R., Jackson, P. S., Lieberson, R. E., Chang, S. D., Adler, J. R. 2010; 67 (5): 1180-1188

    Abstract

    The optimal management of subtotally resected atypical meningiomas is unknown.To perform a retrospective review of patients with residual or recurrent atypical meningiomas treated with stereotactic radiosurgery (SRS).Twenty-five patients were treated, either immediately after surgery (n = 15) or at the time of radiographic progression or treatment failure (n = 10). SRS was delivered to with a median marginal dose of 22 Gy (range, 16-30) in 1 to 4 fractions (median, 1), targeting a median tumor volume of 5.3 cm³ (range, 0.3-26.0).With a median follow-up time of 28 months (range, 3-67), the 12-, 24-, and 36-month actuarial local and regional control rates for all patients were 94%, 94%, 74%, and 90%, 90%, 62%, respectively. There were 2 cases of radiation toxicity. On univariate analysis, the number of recurrences before SRS (P = .046), late SRS (ie, waiting until tumor progression to initiate treatment) (P = .03), and age at treatment ? 60 years (P = .01) were significant predictors of recurrence. Of the 20 radiation-naïve patients, 2 patients failed with the targeted lesion and 3 elsewhere in the resection bed, resulting in 12-, 24- and 36-month actuarial local and regional control rates of 100%, 100%, 73% and 93%, 93%, 75%, respectively. The overall locoregional control rates at 12, 24, and 36 months were 93%, 93%, and 54%, respectively.Irradiation of the entire postoperative tumor bed may not be necessary for the majority of patients with subtotally resected atypical meningiomas. Patients in this series achieved outcomes comparable to that of historical control rates for larger volume, conventionally fractionated radiotherapy.

    View details for DOI 10.1227/NEU.0b013e3181f2f427

    View details for Web of Science ID 000283479500003

    View details for PubMedID 20871435

  • STEREOTACTIC RADIOSURGERY FOR TREATMENT OF SPINAL METASTASES RECURRING IN CLOSE PROXIMITY TO PREVIOUSLY IRRADIATED SPINAL CORD INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Choi, C. Y., Adler, J. R., Gibbs, I. C., Chang, S. D., Jackson, P. S., Minn, A. Y., Lieberson, R. E., Soltys, S. G. 2010; 78 (2): 499-506

    Abstract

    As the spinal cord tolerance often precludes reirradiation with conventional techniques, local recurrence within a previously irradiated field presents a treatment challenge.We retrospectively reviewed 51 lesions in 42 patients treated from 2002 to 2008 whose spinal metastases recurred in a previous radiation field (median previous spinal cord dose of 40 Gy) and were subsequently treated with stereotactic radiosurgery (SRS).SRS was delivered to a median marginal dose of 20 Gy (range, 10-30 Gy) in 1-5 fractions (median, 2), targeting a median tumor volume of 10.3 cm(3) (range, 0.2-128.6 cm(3)). Converting the SRS regimens with the linear quadratic model (?/? = 3), the median spinal cord maximum single-session equivalent dose (SSED) was 12.1 Gy(3) (range, 4.7-19.3 Gy(3)). With a median follow-up of 7 months (range, 2-47 months), the Kaplan-Meier local control and overall survival rates at 6/12 months were 87%/73% and 81%/68%, respectively. A time to retreatment of ?12 months and the combination of time to retreatment of ?12 months with an SSED of <15 Gy(10) were significant predictors of local failure on univariate and multivariate analyses. In patients with a retreatment interval of <12 months, 6/12 month local control rates were 88%/58%, with a SSED of >15 Gy(10), compared to 45%/0% with <15 Gy(10), respectively. One patient (2%) experienced Grade 4 neurotoxicity.SRS is safe and effective in the treatment of spinal metastases recurring in previously irradiated fields. Tumor recurrence within 12 months may correlate with biologic aggressiveness and require higher SRS doses (SSED >15 Gy(10)). Further research is needed to define the partial volume retreatment tolerance of the spinal cord and the optimal target dose.

    View details for DOI 10.1016/j.ijrobp.2009.07.1727

    View details for Web of Science ID 000282147000028

    View details for PubMedID 20133079

  • SPINAL CORD TOLERANCE FOR STEREOTACTIC BODY RADIOTHERAPY INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Sahgal, A., Ma, L., Gibbs, I., Gerszten, P. C., Ryu, S., Soltys, S., Weinberg, V., Wong, S., Chang, E., Fowler, J., Larson, D. A. 2010; 77 (2): 548-553

    Abstract

    Dosimetric data are reported for five cases of radiation-induced myelopathy after stereotactic body radiotherapy (SBRT) to spinal tumors. Analysis per the biologically effective dose (BED) model was performed.Five patients with radiation myelopathy were compared to a subset of 19 patients with no radiation myelopathy post-SBRT. In all patients, the thecal sac was contoured to represent the spinal cord, and doses to the maximum point, 0.1-, 1-, 2-, and 5-cc volumes, were analyzed. The mean normalized 2-Gy-equivalent BEDs (nBEDs), calculated using an alpha/beta value of 2 for late toxicity with units Gy 2/2, were compared using the t test and analysis of variance test.Radiation myelopathy was observed at the maximum point with doses of 25.6 Gy in two fractions, 30.9 Gy in three fractions, and 14.8, 13.1, and 10.6 Gy in one fraction. Overall, there was a significant interaction between patient subsets and volume based on the nBED (p = 0.0003). Given individual volumes, a significant difference was observed for the mean maximum point nBED (p = 0.01).The maximum point dose should be respected for spine SBRT. For single-fraction SBRT 10 Gy to a maximum point is safe, and up to five fractions an nBED of 30 to 35 Gy 2/2 to the thecal sac also poses a low risk of radiation myelopathy.

    View details for DOI 10.1016/j.ijrobp.2009.05.023

    View details for Web of Science ID 000278167500033

    View details for PubMedID 19765914

  • MULTISESSION CYBERKNIFE STEREOTACTIC RADIOSURGERY OF LARGE, BENIGN CRANIAL BASE TUMORS: PRELIMINARY STUDY NEUROSURGERY Tuniz, F., Soltys, S. G., Choi, C. Y., Chang, S. D., Gibbs, I. C., Fischbein, N. J., Adler, J. R. 2009; 65 (5): 898-907

    Abstract

    Although radiosurgery plays an important role in managing benign cranial base lesions, the potential for increased toxicity with single-session treatment of large tumors is a concern. In this retrospective study, we report the intermediate-term rate of local control, morbidity, and clinical outcomes of patients with large cranial base tumors treated with multisession stereotactic radiosurgery with the CyberKnife (Accuray, Inc., Sunnyvale, CA).Between 1999 and 2008, 34 consecutive patients with large (>15 cm), benign cranial base tumors (21 meningiomas, 9 schwannomas, 4 glomus jugulare tumors) underwent primary or postoperative radiosurgical treatment using a multisession approach at Stanford University and were considered in this retrospective study. Forty-four percent of these patients had undergone previous subtotal surgical resection or radiotherapy. CyberKnife radiosurgery was delivered in 2 to 5 sessions (median, 3 sessions) to a median tumor volume of 19.3 cm (range, 15.8-69.3 cm). The median marginal dose was 24 Gy (range, 18-25 Gy) prescribed to a median 78% isodose line.After a median clinical follow-up of 31 months (range, 12-77 months), 21% of patients experienced clinical improvement of neurological symptoms, whereas neurological status remained unchanged among the rest. Four patients experienced prolonged use of glucocorticoids owing to transient neurological worsening and radiographic signs of radiation injury. No permanent neurotoxicity was seen. To date, all tumors remain locally controlled.Over our modest length of follow-up, multisession radiosurgery appears to be a safe and effective option for selected large, benign brain and cranial base lesions.

    View details for DOI 10.1227/01.NEU.0000359316.34041.A8

    View details for Web of Science ID 000270876100013

    View details for PubMedID 19834402

  • STEREOTACTIC RADIOSURGICAL TREATMENT OF CRANIAL AND SPINAL HEMANGIOBLASTOMAS NEUROSURGERY Moss, J. M., Choi, C. Y., Adler, J. R., Soltys, S. G., Gibbs, I. C., Chang, S. D. 2009; 65 (1): 79-85

    Abstract

    Stereotactic radiosurgery has been used for nearly 2 decades to treat hemangioblastomas, particularly those that are in surgically inaccessible locations or that are multiple, as is common in von Hippel-Lindau disease. There is a paucity of long-term published radiosurgical treatment outcomes, particularly for spinal lesions, in a large patient population. The purpose of this study was to provide a long-term retrospective evaluation of radiosurgical hemangioblastoma treatment effectiveness, with a special emphasis on the relatively recent use of frameless, image-guided radiosurgery in the treatment of spinal lesions.From 1991 to 2007, 92 hemangioblastomas in 31 patients, 26 with von Hippel-Lindau disease, were treated with radiosurgery (27 tumors treated with frame-based linear accelerator radiosurgery, and 67 tumors were treated with CyberKnife radiosurgery). The mean patient age was 41 years (range, 18-81 years). The radiation dose to the tumor periphery averaged 23.4 Gy (range, 12-40 Gy). The mean tumor volume was 1.8 cm (range, 0.058-65.4 cm). Tumor response was evaluated in serial, contrast-enhanced, computed tomographic, and magnetic resonance imaging scans.Clinical and radiographic follow-up data were available for 82 hemangioblastoma tumors. Only 13 (16%) of the treated hemangioblastomas progressed, whereas 18 tumors (22%) showed radiographic regression, and 51 tumors (62%) remained unchanged in size. With median follow-up of 69 months (range, 5-164 months), the actuarial local control rates at 36 and 60 months were 85% and 82%, respectively. Radiosurgery improved lesion-associated symptoms in 36 of 41 tumors. During the follow-up period, 9 patients died of causes unrelated to the progression of their treated hemangioblastomas, and 5 patients developed radiation necrosis.Stereotactic radiosurgery is safe and effective in the treatment of hemangioblastomas and is an attractive alternative to surgery for patients, including those with von Hippel-Lindau disease.

    View details for DOI 10.1227/01.NEU.0000348015.51685.D2

    View details for Web of Science ID 000268265600010

    View details for PubMedID 19574828

  • CYBERKNIFE FOR BRAIN METASTASES OF MALIGNANT MELANOMA AND RENAL CELL CARCINOMA NEUROSURGERY Hara, W., Tran, P., Li, G., Su, Z., Puataweepong, P., Adler, J. R., Soltys, S. G., Chang, S. D., Gibbs, I. C. 2009; 64 (2): A26-A32

    Abstract

    To evaluate the efficacy of CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiosurgery (SRS) for patients with brain metastases of malignant melanoma and renal cell carcinoma.We conducted a retrospective review of all patients treated by image-guided radiosurgery at our institution between March 1999 and December 2005. Sixty-two patients with 145 brain metastases of renal cell carcinoma or melanoma were identified.The median follow-up period was 10.5 months. Forty-four patients had malignant melanoma, and 18 patients had renal cell carcinoma. The median age was 57 years, and patients were classified as recursive partitioning analysis Class 1 (6 patients), 2 (52 patients) or 3 (4 patients). Thirty-three patients had been treated systemically with either chemotherapy or immunotherapy, and 33 patients were taking corticosteroids at the time of treatment. The mean tumor volume was 1.47 mL (range, 0.02-35.7 mL), and the mean prescribed dose was 20 Gy (range, 14-24 Gy). The median survival after SRS was 8.3 months. Actuarial survival at 6 and 12 months was 57 and 37%, respectively. On multivariate analysis, Karnofsky Performance Scale score (P < 0.01) and previous immunotherapy/clinical trial (P = 0.01) significantly affected overall survival. One-year intracranial progression-free survival was 38%, and local control was 87%. Intracranial control was impacted by whole-brain radiotherapy (P = 0.01), previous chemotherapy (P = 0.01), and control of the primary at the time of SRS (P = 0.02). Surgical resection had no effect on intracranial or local control. Radiographic evidence of radiation necrosis developed in 4 patients (6%).CyberKnife radiosurgery provided excellent local control with acceptable toxicity in patients with melanoma or renal cell brain metastases. Initial SRS alone appeared to be a reasonable option, as survival was dictated by systemic disease.

    View details for DOI 10.1227/01.NEU.0000339118.55334.EA

    View details for Web of Science ID 000262797700009

    View details for PubMedID 19165071

  • NONISOCENTRIC RADIOSURGICAL RHIZOTOMY FOR TRIGEMINAL NEURALGIA NEUROSURGERY Adler, J. R., Bower, R., Gupta, G., Lim, M., Efron, A., Gibbs, I. C., Chang, S. D., Soltys, S. G. 2009; 64 (2): A84-A90

    Abstract

    Although stereotactic radiosurgery is an established procedure for treating trigeminal neuralgia (TN), the likelihood of a prompt and durable complete response is not assured. Moreover, the incidence of facial numbness remains a challenge. To address these limitations, a new, more anatomic radiosurgical procedure was developed that uses the CyberKnife (Accuray, Inc., Sunnyvale, CA) to lesion an elongated segment of the retrogasserian cisternal portion of the trigeminal sensory root. Because the initial experience with this approach resulted in an unacceptably high incidence of facial numbness, a gradual dose and volume de-escalation was performed over several years. In this single-institution prospective study, we evaluated clinical outcomes in a group of TN patients who underwent lesioning with seemingly optimized nonisocentric radiosurgical parameters.Forty-six patients with intractable idiopathic TN were treated between January 2005 and June 2007. Eligible patients were either poor surgical candidates or had failed previous microvascular decompression or destructive procedures. During a single radiosurgical session, a 6-mm segment of the affected nerve was treated with a mean marginal prescription dose of 58.3 Gy and a mean maximal dose of 73.5 Gy. Monthly neurosurgical follow-up was performed until the patient became pain-free. Longer-term follow-up was performed both in the clinic and over the telephone. Outcomes were graded as excellent (pain-free and off medication), good (>90% improvement while still on medication), fair (50-90% improvement), or poor (no change or worse). Facial numbness was assessed using the Barrow Neurological Institute Facial Numbness Scale score.Symptoms disappeared completely in 39 patients (85%) after a mean latency of 5.2 weeks. In most of these patients, pain relief began within the first week. TN recurred in a single patient after a pain-free interval of 7 months; all symptoms abated after a second radiosurgical procedure. Four additional patients underwent a repeat rhizotomy after failing to respond adequately to the first operation. After a mean follow-up period of 14.7 months, patient-reported outcomes were excellent in 33 patients (72%), good in 11 patients (24%), and poor/no improvement in 2 patients (4%). Significant ipsilateral facial numbness (Grade III on the Barrow Neurological Institute Scale) was reported in 7 patients (15%).Optimized nonisocentric CyberKnife parameters for TN treatment resulted in high rates of pain relief and a more acceptable incidence of facial numbness than reported previously. Longer follow-up periods will be required to establish whether or not the durability of symptom relief after lesioning an elongated segment of the trigeminal root is superior to isocentric radiosurgical rhizotomy.

    View details for DOI 10.1227/01.NEU.0000341631.49154.62

    View details for Web of Science ID 000262797700016

    View details for PubMedID 19165079

  • Stereotactic radiosurgery for a cardiac sarcoma: A case report TECHNOLOGY IN CANCER RESEARCH & TREATMENT Soltys, S. G., Kalani, M. Y., Cheshier, S. H., Szabo, K. A., Lo, A., Chang, S. D. 2008; 7 (5): 363-367

    Abstract

    Pulmonary artery intimal sarcoma is an uncommon tumor with a poor prognosis. We report a case of a 75-year-old man with a pulmonary artery sarcoma, recurrent following surgical resection. To palliate symptoms of this recurrence, he underwent CyberKnife stereotactic radiosurgery with a clinical and radiographic response of his treated disease. No acute or sub-acute toxicity was seen until the patient's death due to metastatic disease 10 weeks following treatment. The feasibility and short-term safety of this technique are reviewed, with emphasis on the stereotactic planning considerations, such as mediastinal organ movement and radiation tolerance.

    View details for Web of Science ID 000259799000003

    View details for PubMedID 18783285

  • Predictors of peritumoral edema after stereotactic radiosurgery of supratentorial meningiomas NEUROSURGERY Patil, C. G., Hoang, S., Borchers, D. J., Sakamoto, G., Soltys, S. G., Gibbs, I. C., Harsh, G. R., Chang, S. D., Adler, J. R. 2008; 63 (3): 435-440

    Abstract

    Anecdotal evidence suggests that radiosurgical ablation of parasagittal meningiomas may be associated with increased risk of subsequent edema. Potential predictors of postradiosurgical peritumoral edema, including parasagittal tumor location, tumor size, and treatment dose, were evaluated.We retrospectively reviewed records of 102 patients with 111 supratentorial meningiomas treated with CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiosurgery (SRS). A median marginal dose of 18.0 Gy (range, 11.3-25.0 Gy) was delivered in 1 to 5 sessions (fractions). Potential predictors of posttreatment symptomatic edema were evaluated using Fisher's exact test.Of the 102 patients followed for a mean of 20.9 months (range, 6-77 mo), 15 (14.7%) developed symptomatic edema after SRS. Nine of 31 with parasagittal meningiomas (29.0%) and 6 of 80 with nonparasagittal supratentorial meningiomas (7.5%) developed symptomatic edema (P = 0.0053). Compared with patients with meningiomas in nonmidline supratentorial locations, patients with parasagittal meningiomas were more than 4 times as likely to develop symptomatic edema after SRS (odds ratio, 4.1; 95% confidence interval, 1.5-11.5). The 6-, 12-, and 18-month actuarial rates of symptomatic edema development were significantly greater for patients with parasagittal meningiomas than for patients with nonparasagittal meningiomas (17.8 versus 1.3%, 25.4 versus 5.8%, and 35.2 versus 7.8%, respectively).Patients with parasagittal meningiomas are at greater risk of developing peritumoral symptomatic edema after SRS. Close follow-up after SRS may be particularly important in such patients. These results highlight the need to pursue strategies that could decrease the incidence of postradiosurgical edema in patients with parasagittal meningioma.

    View details for Web of Science ID 000259625600010

    View details for PubMedID 18812954

  • Survival following CyberKnife radiosurgery and hypofractionated radiotherapy for newly diagnosed glioblastoma multiforme TECHNOLOGY IN CANCER RESEARCH & TREATMENT Lipani, J. D., Jackson, P. S., Soltys, S. G., Sato, K., Adler, J. R. 2008; 7 (3): 249-255

    Abstract

    Current therapeutic goals for treatment of Glioblastoma Multiforme (GBM) involve gross total resection followed by multifractionated focal external beam radiation therapy (EBRT). Patients treated with optimal therapy have a median survival of approximately 12-15 months. In the present study, we sought to determine whether a hypofractionated dosing schedule using CyberKnife is at least as effective as multifractionated focal EBRT. A retrospective analysis was conducted on 20 histopathologically confirmed GBM patients treated with CyberKnife at Okayama Kyokuto Hospital in Japan after gross total resection (n=11), subtotal resection (n=8), or biopsy (n=1). Eight patients also received adjuvant ACNU and Vincrisitine chemotherapy according to local protocol; however, no patient received any other form of radiation besides post surgical/biopsy CyberKnife treatment. The treated tumor volumes ranged from 9.62 cm(3)-185.81 cm(3) (mean: 86.08 cm(3)). The marginal dose (D90) ranged from 19.99 Gy-41.47 Gy (mean: 34.58 Gy) with a maximum mean dose of 43.99 Gy (range: 23.33 Gy-56.89 Gy). The prescribed isodose line ranged from 50.38%-85.68% with a mean of 79.25%. Treatment was delivered in 1-8 fractions (mean: 5.65). Patients were followed from 2-36 months (mean: 16.45 months). Overall median survival was 16 months with 55% of patients alive at 12 months and 34% of patients alive at 24 months. Median survival of patients in Recursive Partitioning Analysis (RPA) classes III or IV was 32 months versus 12 months for those in RPA class V. Median survival for patients who received gross total resection was 36 months versus 8 months for those who underwent subtotal resection or biopsy. The results of this study using CyberKnife stereotactic radiosurgery (SRS) and hypofractionated radiotherapy compared favorably to historic data using focal EBRT in newly diagnosed post surgical GBM patients. A larger prospective analysis that compares CyberKnife SRS and hypofractionated radiotherapy to focal EBRT is warranted.

    View details for Web of Science ID 000256746700011

    View details for PubMedID 18473497

  • Stereotactic radiosurgery of the postoperative resection cavity for brain metastases INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Soltys, S. G., Adler, J. R., Lipani, J. D., Jackson, P. S., Choi, C. Y., Puataweepong, P., White, S., Gibbs, I. C., Chang, S. D. 2008; 70 (1): 187-193

    Abstract

    The purpose of this study was to analyze results of adjuvant stereotactic radiosurgery (SRS) targeted at resection cavities of brain metastases without whole-brain irradiation (WBI).Patients who underwent SRS to the tumor bed, deferring WBI after resection of a brain metastasis, were retrospectively identified.Seventy-two patients with 76 cavities treated from 1998 to 2006 met inclusion criteria. The SRS was delivered to a median marginal dose of 18.6 Gy (range, 15-30 Gy) targeting an average tumor volume of 9.8 cm(3) (range, 0.1-66.8 cm(3)). With a median follow-up of 8.1 months (range, 0.1-80.5 months), 65 patients had follow-up imaging assessable for control analyses. Actuarial local control rates at 6 and 12 months were 88% and 79%, respectively. On univariate analysis, increasing values of conformality indices were the only treatment variables that correlated significantly with improved local control; local control was 100% for the least conformal quartile compared with 63% for the remaining quartiles. Target volume, dose, and number of sessions were not statistically significant.In this retrospective series, SRS administered to the resection cavity of brain metastases resulted in a 79% local control rate at 12 months. This value compares favorably with historic results with observation alone (54%) and postoperative WBI (80-90%). Given the improved local control seen with less conformal plans, we recommend inclusion of a 2-mm margin around the resection cavity when using this technique.

    View details for DOI 10.1016/j.ijrobp.2007.06.068

    View details for Web of Science ID 000251867700026

    View details for PubMedID 17881139

  • CyberKnife (R) robotic radiosurgery system for tumor treatment EXPERT REVIEW OF ANTICANCER THERAPY Hara, W., Soltys, S. G., Gibbs, I. C. 2007; 7 (11): 1507-1515

    Abstract

    Defined by its high level of accuracy and rapid radiation dose fall-off, radiosurgery has emerged as an effective radiation technique over the past few decades. Although it was once limited to conditions of the brain, head and neck regions, technological advances in computing and imaging have allowed the application of radiosurgery to conditions throughout the entire body. Using advanced imaging and robotics, the CyberKnife (Accuray, Inc., Sunnyvale, CA, USA) is one of few systems capable of delivering radiosurgery with exquisite accuracy to tumors, cancers and other conditions throughout the body. This review focuses on the development, technology, clinical efficacy and future directions of the CyberKnife.

    View details for DOI 10.1586/14737140.7-11.1507

    View details for Web of Science ID 000251444300009

    View details for PubMedID 18020920

  • CyberKnife rhizotomy for facetogenic back pain: a pilot study. Neurosurgical focus Li, G., Patil, C., Adler, J. R., Lad, S. P., Soltys, S. G., Gibbs, I. C., Tupper, L., Boakye, M. 2007; 23 (6): E2-?

    Abstract

    By targeting the medial branches of the dorsal rami, radiofrequency ablation and facet joint injections can provide temporary amelioration of facet joint-producing (or facetogenic) back pain. The authors used CyberKnife radiosurgery to denervate affected facet joints with the goal of obtaining a less invasive yet more thorough and durable antinociceptive rhizotomy.Patients with refractory low-back pain, in whom symptoms are temporarily resolved by facet joint injections, were eligible. The patients were required to exhibit positron emission tomography-positive findings at the affected levels. Radiosurgical rhizotomy, targeting the facet joint, was performed in a single session with a marginal prescription dose of 40 Gy and a maximal dose of 60 Gy.Seven facet joints in 5 patients with presumptive facetogenic back pain underwent CyberKnife lesioning. The median follow-up was 9.8 months (range 3-16 months). The mean planning target volume was 1.7 cm(3) (range 0.9-2.7 cm(3)). A dose of 40 Gy was prescribed to a mean isodose line of 79% (range 75-80%). Within 1 month of radiosurgery, improvement in pain was observed in 3 of the 5 patients with durable responses at 16, 12, and 6 months, respectively, of follow-up. Two patients, after 12 and 3 months of follow-up, have neither improved nor worsened. No patient has experienced acute or late-onset toxicity.These preliminary results suggest that CyberKnife radiosurgery could be a safe, effective, and non-invasive alternative to radiofrequency ablation for managing facetogenic back pain. No patient suffered recurrent symptoms after radiosurgery. It is not yet known whether pain relief due to such lesions will be more durable than that produced by alternative procedures. A larger series of patients with long-term follow-up is ongoing.

    View details for PubMedID 18081475

  • Efficacy and safety of CyberKnife radiosurgery for acromegaly. Pituitary Roberts, B. K., Ouyang, D. L., Lad, S. P., Chang, S. D., Harsh, G. R., Adler, J. R., Soltys, S. G., Gibbs, I. C., Remedios, L., Katznelson, L. 2007; 10 (1): 19-25

    Abstract

    Acromegaly is a disease characterized by GH hypersecretion, and is typically caused by a pituitary somatotroph adenoma. The primary mode of therapy is surgery, and radiotherapy is utilized as an adjuvant strategy to treat persistent disease. The aim of this study was to determine the efficacy and tolerability of CyberKnife stereotactic radiosurgery in acromegaly.A retrospective review of biochemical and imaging data for subjects with acromegaly treated with CyberKnife stereotactic radiosurgery between 1998 and 2005 at Stanford University Hospital.Nine patients with active acromegaly were treated with radiosurgery using the CyberKnife (CK).Biochemical response based on serum insulin-like growth factor-1 (IGF-1), anterior pituitary hormone function, and tumor size with MRI scans were analyzed.After a mean follow up of 25.4 months (range, 6-53 months), CK radiosurgery resulted in complete biochemical remission in 4 (44.4%) subjects, and in biochemical control with the concomitant use of a somatostatin analog in an additional subject. Smaller tumor size was predictive of treatment success: baseline tumor volume was 1.28 cc (+/- 0.81, SD) vs. 3.93 cc (+/- 1.54) in subjects with a normal IGF-1 vs. those with persistent, active disease, respectively (P = 0.02). The mean biologically effective dose (BED) was higher in subjects who achieved a normal IGF-1 vs. those with persistent, active disease, 172 Gy(3) (+/-28) vs. 94 Gy(3) (+/-17), respectively (P < 0.01). At least one new anterior pituitary hormone deficiency was observed after CK in 3 (33%) patients: two developed hypogonadism, and one developed panhypopituitarism.CK radiosurgery may be a valuable adjuvant therapy for the management of acromegaly.

    View details for PubMedID 17273921

  • Sample classification from protein mass spectrometry, by 'peak probability contrasts' BIOINFORMATICS Tibshirani, R., Hastie, T., Narasimhan, B., Soltys, S., Shi, G. Y., Koong, A., Le, Q. T. 2004; 20 (17): 3034-3044

    Abstract

    Early cancer detection has always been a major research focus in solid tumor oncology. Early tumor detection can theoretically result in lower stage tumors, more treatable diseases and ultimately higher cure rates with less treatment-related morbidities. Protein mass spectrometry is a potentially powerful tool for early cancer detection. We propose a novel method for sample classification from protein mass spectrometry data. When applied to spectra from both diseased and healthy patients, the 'peak probability contrast' technique provides a list of all common peaks among the spectra, their statistical significance and their relative importance in discriminating between the two groups. We illustrate the method on matrix-assisted laser desorption and ionization mass spectrometry data from a study of ovarian cancers.Compared to other statistical approaches for class prediction, the peak probability contrast method performs as well or better than several methods that require the full spectra, rather than just labelled peaks. It is also much more interpretable biologically. The peak probability contrast method is a potentially useful tool for sample classification from protein mass spectrometry data.

    View details for DOI 10.1093/bioinformatics/bth357

    View details for Web of Science ID 000225361400017

    View details for PubMedID 15226172

  • The use of plasma surface-enhanced laser desorption/ionization time-of-flight mass spectrometry proteomic patterns for detection of head and neck squamous cell cancers CLINICAL CANCER RESEARCH Soltys, S. G., Le, Q. T., Shi, G. Y., Tibshirani, R., Giaccia, A. J., Koong, A. C. 2004; 10 (14): 4806-4812

    Abstract

    Our study was undertaken to determine the utility of plasma proteomic profiling using surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry for the detection of head and neck squamous cell carcinomas (HNSCCs).Pretreatment plasma samples from HNSCC patients or controls without known neoplastic disease were analyzed on the Protein Biology System IIc SELDI-TOF mass spectrometer (Ciphergen Biosystems, Fremont, CA). Proteomic spectra of mass:charge ratio (m/z) were generated by the application of plasma to immobilized metal-affinity-capture (IMAC) ProteinChip arrays activated with copper. A total of 37356 data points were generated for each sample. A training set of spectra from 56 cancer patients and 52 controls were applied to the "Lasso" technique to identify protein profiles that can distinguish cancer from noncancer, and cross-validation was used to determine test errors in this training set. The discovery pattern was then used to classify a separate masked test set of 57 cancer and 52 controls. In total, we analyzed the proteomic spectra of 113 cancer patients and 104 controls.The Lasso approach identified 65 significant data points for the discrimination of normal from cancer profiles. The discriminatory pattern correctly identified 39 of 57 HNSCC patients and 40 of 52 noncancer controls in the masked test set. These results yielded a sensitivity of 68% and specificity of 73%. Subgroup analyses in the test set of four different demographic factors (age, gender, and cigarette and alcohol use) that can potentially confound the interpretation of the results suggest that this model tended to overpredict cancer in control smokers.Plasma proteomic profiling with SELDI-TOF mass spectrometry provides moderate sensitivity and specificity in discriminating HNSCC. Further improvement and validation of this approach is needed to determine its usefulness in screening for this disease.

    View details for Web of Science ID 000222840700027

    View details for PubMedID 15269156

  • Human papillomavirus and p53 mutational status as prognostic factors in head and neck carcinoma HEAD AND NECK-JOURNAL FOR THE SCIENCES AND SPECIALTIES OF THE HEAD AND NECK Sisk, E. A., Soltys, S. G., ZHU, S. B., Fisher, S. G., Carey, T. E., Bradford, C. R. 2002; 24 (9): 841-849

    Abstract

    Mutations of the p53 tumor-suppressor gene are common in squamous cell carcinoma of the head and neck (SCCHN) and may portend a worse prognosis. Human papillomavirus (HPV) represents another potential prognostic factor for SCCHN. The oncogenic potential of HPV may be due to the ability of its E6 oncoprotein to promote degradation of wild-type p53 protein. We wish to determine whether there is a lower incidence of p53 mutations in HPV-positive versus HPV-negative tumors, and if HPV and/or p53 status has an impact on survival.Thirty-two SCCHN specimens were analyzed for mutations of the p53 gene using single-strand conformational polymorphism (SSCP) analysis followed by DNA sequencing. The HPV status of all specimens was evaluated by use of polymerase chain reaction with HPV consensus primers and Southern blot hybridization. Pertinent clinical information was obtained from chart review.Nonsilent p53 mutations were present in 2 of 15 (13%) of HPV-positive tumors compared with 6 of 17 (35%) of HPV-negative tumors (p =.229; Fisher's exact test, odds ratio.28). A survival advantage was found between HPV-positive compared with HPV-negative specimens (p =.0264) and between p53 wild type compared with p53 mutant specimens (p =.01) by univariate log rank analysis. When stratified according to both HPV and p53 status, a statistically significant survival difference was observed largely because of a 100% survival for the HPV-positive/p53 wild-type group (p =.003).This preliminary study supports the notion that the presence of HPV confers a survival advantage among HNSCC patients, particularly when p53 is wild type.

    View details for DOI 10.1002/hed.10146

    View details for Web of Science ID 000177651400003

    View details for PubMedID 12211048

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