Brain Cancer

Treatment

There are four general therapeutic tools at your disposal.

Chemotherapy

Chemotherapy is the use of medication to treat tumors.

Most chemotherapeutic agents are incorporated into and alkylate the DNA of rapidly dividing tumor cells. Alkylation is the process by which an alkyl group is added, which in turn disrupts the cell cycle – and so the growth – of the tumor cells. Chemotherapy drugs may be cell-cycle specific, acting only during certain cycles of the cell, or they may be non cell-cycle specific, and so are effective at any point of the cell cycle. A combination of cell-cycle specific and non cell-cycle specific may also be used to treat larger numbers of tumor cells.

Cell-cycle specific drugs include: Hormones, Steroids, Etoposide (VP-16), Hydroxyurea, Methotrexate (MTX), Procarbozine and Temozolomide (Temodar).

Non Cell-Cycle Specific Drugs include: Nitrosureas – Carmustine (BCNU), Lomustine (CCNU), Becacizumab (Avastin), Cilengitide (EMD121974), Cisplatin (CDDP) Irinotecan (CPT-11), Rapamycin and Vincristine.

The nitrosureas are unique chemotherapeutic agents in that they can cross the blood-brain barrier (selective barrier preventing blood and substances carried within from entering the central nervous system). Some chemotherapeutic agents also enhance the effect of radiation therapy.

The problems with chemotherapy in brain tumors concern drug delivery and specificity. The effect of any chemotherapeutic agent is directly related to the dose given. Chemotherapy, usually given intravenously, adversely affects rapidly dividing tumor cells (which is good). However, chemotherapy can also affect rapidly dividing normal cells in the bowel and bone marrow. This results in nausea, vomiting and other gastrointestinal disturbances as well as bone marrow suppression with reduction of white blood cells (resulting in a reduced capacity to fight infection), reduction of red blood cells (anemia) and reduction of platelets (thrombocytopenia), resulting in blood clotting disorders and bleeding. These side effects occur because the chemotherapy injected into the patient’s blood stream goes everywhere in addition to the brain and the tumor.

Radiation Therapy

Radiation Therapy is the use of ionizing radiation or radioactive sources to treat tumors.

Standard radiation therapy is not given in one single treatment. Instead, radiation therapy is a series of daily treatments usually administered over a six-week period in “fractions”: part of the total dose is given every day, five days a week for six weeks.

Conformal radiation therapy is when the radiation dose is better focused on the MRI or CT-defined abnormality.

Ionizing radiation damages the DNA in all cells. Normal cells can repair the damage quickly; tumor cells cannot. Radiation therapy is given in small daily doses (fractionated), which allow the normal cells to repair the damage between doses. A typical course of radiation therapy consists of five daily treatments per week over a six week period of time. In order to minimize the dose of radiation given to the scalp and overlying brain tissue, the radiation beam is usually directed from several angles toward the brain tumor by a device called a linear accelerator.

Radiosurgery

Radiosurgery is the use of focused, ionized beams of radiation delivered from multiple points surrounding the head to treat tumors.

Radiosurgery is best for relatively small, circumscribed tumors – meaning boundaries between the tumor and surrounding brain are definite and sharp. Radiosurgery is non-invasive and nonsurgical. Some patients with brain tumors are candidates for this type of treatment.

Radiosurgery is usually not the “last resort” for patients with large, recurrent Glioblastomas. It is also not appropriate for infiltrating glial tumors. The best candidates for radiosurgery are patients harboring small, geometrically regular, slow growing tumors for which removal would be too risky. These tumors include small Acoustic Neurinomas (usually in elderly or medically unstable patients), some pituitary tumors, small Meningiomas (especially those at the skull base, i.e. the cavernous sinus) and small, geometrically regular Gliomas. Selected patients with metastatic tumors are also good patients for radiosurgery. Very vascular metastatic tumors such as renal cell carcinoma do especially well with radiosurgery. In addition, patients with multiple metastatic tumors have been treated with multiple shots of radiosurgery to treat each tumor. This may be found to have some advantages over whole brain irradiation which is the standard treatment for multiple metastases.

Surgery

Surgery is the removal of part or all of a tumor.

Some brain tumors can be cured by surgery. These include Acoustic Neurinomas, many Meningiomas, Pituitary Adenomas, Pinealomas, Pilocytic Astrocytomas and some others. Nonetheless, MRI scans are suggested every 3-6 months for the first year following surgery and every 1-2 years thereafter to be sure that there is no recurrence.

If you need adjuvant treatment: Find an experienced neuro-oncologist and/or radiation oncologist.