Treatments

Surgical resection aims to remove as much tumor as possible while minimizing the risk to normal brain tissue – what we call maximal safe resection. Surgical resection reduces the amount of tumor tissue within the brain (tumor debulking), improves response to radiation and chemotherapy, relieves symptoms, and lowers intracranial pressure.

Advanced imaging and various intraoperative techniques are used to maximize tumor resection and minimize damage to the normal brain. Some intraoperative methods include:

• Neuronavigation: use of specialized software and hardware to create a 3D map of the brain and to track the position of surgical instruments in relation to the map.
• Laser interstitial thermal therapy (LITT): a minimally invasive technique where the surgeon creates a small incision in the scalp and insert a laser probe into the brain tissue. The laser is then used to heat and destroy the abnormal tissue.
• Motor mapping (movement stimulation): a technique used during brain surgery to identify and protect the areas of the brain that control movement.
• Fluorescent dyes, such as 5-ALA,  that color the tumor. Fluorescence-guided surgery allows the surgeon to remove the tumor with more precision.
• Microsurgery: surgery with a microscope and special instruments
• Endoscopic neurosurgery: surgery with an endoscope, an instrument that transmits images through a tube, allowing visualization around corners and through a small opening
• Awake surgery with ongoing assessment of movement and language ability
  
  

Unfortunately, some tumor cells inevitably remain. These may continue to grow and eventually lead to a recurrence of the tumor.

In selecting the appropriate surgical approaches for patients, neurosurgeons consider the rate of growth of the tumor and the presence of other symptoms (increased intracranial pressure, bleeding into the tumor, persistent seizures). They also consider the tumor's location.

Radiation therapy (RT) uses ionizing radiation (high-energy beams) to kill tumor cells. RT is frequently prescribed to kill residual (remaining) tumor cells two to four weeks following surgery. It can also be used when surgical resection is unsafe or to relieve symptoms later in the disease course.

RT kills tumor cells by damaging DNA. Normal brain cells are also damaged but are faster to recover. The amount of radiation delivered to normal cells is minimized by carefully selecting the radiation field (area to receive the radiation), the total radiation dose, the timing of treatment, and the delivery method.

• In external beam radiation therapy (EBRT), radiation directed at the tumor is delivered from outside the body using a special machine. Radiation oncologists use CT and MRI scans and sophisticated software to develop a treatment plan and target the glioma. Treatment is usually delivered in a series of treatments called fractions over several weeks.
• Stereotactic radiosurgery is another form of radiation therapy suitable for small tumors. This technique is not surgical (despite its name) but delivers radiation to the tumor from outside the body. It uses many small beams of radiation directed at a point within the tumor. Treatment usually takes place in a single session.
• Proton therapy is a radiation technique that uses protons instead of traditional x-rays. Proton therapy may be used in critical brain areas where damage to nearby tissues would not be tolerated.
   

Short-term side effects of RT usually occur within six weeks of treatment and include fatigue, hair loss, rash, and decreased appetite. Headaches, nausea, and a worsening of neurologic symptoms (seizures, weakness) may also occur.

Cognitive impairment (mild memory loss, confusion, decreased ability to perform complex tasks, poor concentration) sometimes develops months later. It may be caused by the RT, the chemotherapy, or the glioma itself.

Other long-term side effects are cataracts, and rarely, hearing loss, hormonal changes, new tumors, and radiation necrosis (dead tissue formed at the site of radiation).

RT is not curative but helps contain tumor growth and prolongs survival compared with surgery or chemotherapy alone.

Chemotherapy targets cells during their cell cycle when cells are in the process of multiplying. Because cancer cells form new cells faster than most normal cells, chemotherapy has a greater detrimental effect on cancer cells.

Glioma tumors are often treated with temozolomide or PCV (procarbazine, lomustine, vincristine). The drugs are taken orally (as a pill) or intravenously (through a vein).

Since chemotherapy targets rapidly dividing cells, it can affect normal cells that continue to be produced even in adult life, including hair follicles, cells that line the gastrointestinal tract, and blood cells. As such, typical side effects include:

• Increased risk of infection
• Bruising and bleeding
• Shortness of breath and fatigue
• Nausea and vomiting, constipation, and abdominal pain
• Numbness or tingling in fingers and toes, or weakness
• Hair loss
• Fever