Chemotherapy uses cytotoxic drugs to destroy cancer. "Cytotoxic" means toxic for the cells. These drugs do not only alter the way in which cancer cells grow and divide, but they may also affect normal cells.

Chemotherapy can be given:

- Together with radiotherapy or alone as treatment for high-grade glioma (grade 4)

- If a tumor reappears after surgery and radiotherapy

- After surgery performed in lie of radiotherapy if a low-grade glioma has not been eliminated entirely

Chemotherapy can be the main treatment approach used for lymphoma that starts in the brain (lymphoma of the CNS).

• Drugs used

There are many types of chemotherapy drugs used, but not all can be used to treat brain tumors. Drugs must be able to penetrate the brain's natural protection in order to enter the brain and the spinal cord.

The main drugs used to treat primary brain tumors are:

- Temozolomide

- Lomustine, procarbazine, and vincristine given separately or together (called PVC)

- Carmustine

There are different ways of administering chemotherapy to treat brain tumors. Temozolomide, lomustine, and procarbazine are taken in tablet form. Vincristine and carmustine are liquids given intravenously.

• Chemotherapy given alongside radiotherapy.

If a high-grade glioma has been diagnosed recently, it may be treated with temozolomide and radiotherapy together. This is called combined treatment.

Combined treatment causes more side effects, which is why the patient must be in good physical condition. Combined treatment also increases the risk of contracting infections of the chest; you may be given antibiotics in order to lower the chances of this happening.