Chordoma of the Skull Base

Chordoma is a type of bone cancer that belongs to the sarcoma family. This rare cancer affects only one in a million people, which is why it is very difficult to find true expertise in its management. Stanford is one of very few Skull Base Centers with true expertise and innovation in Chordoma treatment worldwide.

Chordomas arise from remnants of notochord, which precedes the spinal column during embryonic development. What causes notochord cells to become cancerous in some people is still not fully known, but researchers are actively working to find the answer. There are no known environmental, dietary, or lifestyle risk factors for chordoma. The vast majority of chordomas occur at random and not as a direct result of an inherited genetic trait.

About 50% occur in the sacrum, the bone at the base of the spine, about 30% occur in the skull base, the area behind the eyes and nose that slopes down to form the “floor” of the skull, and the rest are found along the spine.

A chordoma tumor usually grows slowly, often without symptoms at first, and then might cause symptoms for years before doctors find it. They are difficult tumors to treat due to their deep location and potential involvement of critical neurovascular structures such as the brainstem, spinal cord, optic and oculomotor nerves and carotid arteries.

Symptoms

Clinical presentation depends on location and size of the tumor.

For skull base chordomas, common symptoms include double vision, headaches, and neck pain. If large enough, they may affect facial sensation or movement, voice, speech, and swallowing function. Occasionally, clival chordomas are found incidentally after identification on head imaging performed for unrelated reasons.

Diagnosis

A dedicated skull base MRI scan is the first step in diagnosing chordoma.

It typically shows a clival lesion heterogeneously bright on T2-weighted MRI images. However, diagnosing a skull base chordoma is not always easy, as it can be confused with other types of clival tumors. Once you have been given a diagnosis, it can be helpful to get a second opinion to confirm the diagnosis before making treatment decisions. As with any rare cancer, second and even third opinions are an important and reasonable step to take.

Biopsy and histologic studies are necessary to confirm the diagnosis, and distinguish chordomas from other lesions. However, in experienced hands, an MRI is usually sufficient to suspect the diagnosis of chordoma, obviating the need for undergoing a dedicated procedure for biopsy and proceeding directly with biopsy and surgical resection at the same time.

As recommended by The Chordoma Foundation: “It is important to go to a hospital, treatment center, or network of treatment centers where doctors have experience diagnosing and treating chordoma as soon as chordoma is suspected. You should avoid having a biopsy or surgery to confirm the diagnosis of chordoma outside of a referral center because, if not done properly, these procedures can cause the chordoma to spread… If you cannot travel to see a doctor who has experience with chordoma, have your imaging tests sent to a doctor with chordoma experience for a second opinion before you get treatment or a biopsy.”

At Stanford Skull Base Center we provide complimentary second opinion and remote consultations for patients with suspected or known chordoma.

Treatment

Chordoma treatment begins with surgery.

As stated by The Chordoma Foundation “No matter what stage of the disease you are facing [new, recurrent, advanced, metastatic] or where your tumor is located, the way surgery is performed is very important.”

At Stanford, the preferred surgical treatment for most chordomas of the skull base is the Endoscopic Endonasal Approach (EEA). This innovative, minimally invasive technique uses the nose and nasal cavities as natural corridors to access hard-to-reach or previously inoperable tumors. Dr. Fernandez-Miranda and his team have been at the forefront of the development and refinement of EEA for skull base chordomas, describing multiple anatomical nuances and novel surgical techniques relevant for successful chordoma surgery.

Depending on the size and location of your tumor, it may be necessary to do surgery from multiple directions to safely remove different parts of the tumor. At Stanford, we have expertise with all types of transcranial skull base approaches for those tumors that cannot be totally removed via EEA.

The goal of the Stanford Skull Base team is to perform, whenever possible, a “supratotal” tumor resection, where the entire tumor is removed along with at least 1 millimeter of healthy tissue around the tumor, and at the same time minimize side effects and surgical complications.

When the entire tumor is successfully removed with surgery, patients statistically live longer and the tumor is less likely to recur, or grow back. If your entire tumor was not successfully removed with the first surgery, consider getting a second opinion on removing the remaining tumor before starting radiation.

Chordomas have a high local recurrence rate, meaning they can come back after successful treatment — usually in the same place as the first tumor. This is called a local recurrence. In selected cases, a reoperation is recommended. At Stanford, we have extensive experience treating patients with chordoma recurrence that were considered “inoperable” at other centers.

Even in cases where all visible tumor has been removed, it is still likely that microscopic chordoma cells were left behind during surgery. Therefore, radiation therapy is generally recommended after surgery to prevent any remaining cells from re-growing or spreading to other parts of the body.

Radiation treatments will typically begin within three to six months after surgery. Radiation delivery techniques with particles (protons or carbon ions) or photons (stereotactic radiosurgery [SRS] and intensity modulated radiation therapy [IMRT]) have allowed for higher doses of radiation to be delivered to the tumor while sparing surrounding structures.

Proton beam, carbon ion, and IMRT photon radiation are typically given in small doses during daily sessions (usually around 35-40) over 6-8 weeks. Hypofractionated radiation like SRS are given in larger doses over a shorter amount of time (usually 1-5 sessions). Once you have been treated with a high dose of radiation, it might not be possible for you to have radiation again.

Chemotherapy uses drugs to stop cancer cells from growing. Modern chemotherapy and immunotherapy for chordomas is under investigation at Stanford Cancer Center.