Brain Tumors: Primary - Radiotherapy

Chemotherapy

Chemotherapy uses drugs to kill or alter cancer cells. Chemotherapy is not an effective initial treatment for low-grade brain tumors, mostly because standard drugs have a hard time passing into the brain because of how the brain protects itself (the blood-brain barrier). In addition, not all types of brain tumors respond to chemotherapy. In general, chemotherapy for brain tumors is usually administered following surgery or radiation therapy.

The type of drug determines how it is administered. "Systemic delivery" drugs, which pass to the brain from the bloodstream, may be given by mouth, injected into a vein through an IV, or injected into an artery or a muscle. "Local delivery" drugs are placed within or around the brain tumor.

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Newer delivery methods to overcome some of these problems include:

• Interstitial chemotherapy uses disc-shaped polymer wafers (known as Gliadel wafers) soaked with carmustine, the standard chemotherapeutic drug for brain cancer. The surgeon implants the wafer directly into the surgical cavity after a tumor is removed.
• Intrathecal chemotherapy delivers chemotherapeutic drugs directly into the spinal fluid.
• Intra-arterial chemotherapy delivers high-dose chemotherapy into arteries in the brain using tiny catheters.
• Convection-enhanced delivery (CED) involves placing catheters into the brain tumor or nearby brain tissue to deliver slowly and continuously a cancer drug over several days.

Chemotherapy Drugs and Regimens

Many different drugs, and drug combinations, are used for chemotherapy. Standard ones include:

Temozolomide (Temodar). Temozolomide is approved for adult patients with anaplastic astrocytoma that did not respond to other treatments. It is also approved for use during and after radiation therapy for patients newly diagnosed with glioblastoma multiforme. The current first-line treatment for patients with glioblastoma is combined radiotherapy and temozolomide, followed by monthly doses of temozolomide after radiation treatment ends. The drug may work best for patients with a specific genotype. Temozolomide's side effects are relatively minor, but may include constipation, nausea and vomiting, fatigue, and headache. The drug is taken by mouth as a pill.