Drug therapies for brain tumours

Chemotherapy

Chemotherapy uses drugs to kill or slow the growth of cancer cells. The aim is to destroy cancer cells while causing the least possible damage to healthy cells.

You may have chemotherapy after surgery or radiation therapy. Chemotherapy may also be given at the same time as radiation therapy (chemoradiation). For a brain tumour, you usually have chemotherapy as capsules or tablets that you swallow, but you may also have it as a liquid through a drip inserted into your vein (intravenously).

A structure known as the blood–brain barrier helps protect the brain from substances in the blood, such as germs or chemicals. Only certain types of chemotherapy drugs can get through this barrier.

Temozolomide is the most commonly prescribed chemotherapy drug to treat grade 4 glioma brain tumours. It is given as a capsule you take at home. You will be instructed to take it for a set number of days, which is then followed by a rest period. This is called a cycle.

You are likely to have up to 6 cycles of temozolomide, though it may continue for longer.

Your doctor may suggest a different dosage or another chemotherapy drug that is more suitable for your situation. Other drugs include lomustine and PCV (procarbazine, lomustine and vincristine).

Side effects of chemotherapy

There are many possible side effects of chemotherapy, depending on the type of drugs you are given. Talk to your doctor about ways to reduce or manage any side effects you have. Side effects are mostly mild with temozolomide and may include:

• nausea or vomiting
• tiredness, fatigue and lack of energy
• increased risk of infection
• mouth sores and ulcers
• diarrhoea or constipation
• loss of appetite
• skin rash
• liver damage
• breathlessness due to low levels of red blood cells (anaemia)
• low levels of platelets (thrombocytopenia), increasing the risk of abnormal bleeding
• reduction in the production of blood cells in the bone marrow; you will usually have regular blood tests to monitor your blood levels
• damage to ovaries or testicles, which can make you unable to have children naturally (infertile).

In some cases your hair may become thinner or patchy, but it is rare to lose all your hair with chemotherapy for brain and spinal cord tumours.

Targeted therapy

Targeted therapy is a drug therapy that targets specific features of cancer cells to stop the cancer growing or spreading. These drugs circulate through the body, but work in a more focused way than chemotherapy and often have fewer side effects.

A range of new targeted therapy drugs are being developed to match the molecular profile of each person’s cancer cells. For brain tumours, researchers are studying how to target genes such as BRAF, NTRK and IDH. These advances will help make personalised treatments possible.

Immunotherapy

Immunotherapy is not currently a standard treatment option for primary brain tumours. This is in part because of the way the brain’s immune system works. New immunotherapy drugs are being tested in clinical trials. These include treatments to help the immune system better recognise cancer cells (e.g. nivolumab, pembrolizumab),vaccines against cancer cells (e.g. PEP-CMV, DCVax), viruses to infect cancer cells (e.g. PVSRIPO, G47Δ), and treatments that change the patient’s own immune cells (e.g. CAR-T cell therapy).

Immunotherapy may be used to treat certain types of cancer that have spread to the brain (metastasised).