Although cancers arising from the brain are rare in adults they are second to leukaemias in causing cancer deaths in children.
Patients commonly present with headaches which are characteristically worse in the morning and improve as the day goes on. This headache is often due to swelling of the brain, or cerebral oedema, around the tumour. The pressure builds up overnight but the fluid can redistribute on rising.
A small tumour can do a lot of damage in the brain. First, there are a lot of vital nervous system structures close together and, second, the bony skull confines the brain so that any growth increases the pressure on the brain. The symptoms can be general—drowsiness, headache, nausea, seizures, changes in the ability to concentrate. They can also be specific, depending on which part of the brain is affected. Patients may present with weakness, changes in sensation, problems with vision or speech or changes in personality.
The diagnosis is easily made with CT scans or MRI scans which may suggest the need for a biopsy to tell the type of cancer. The definitive treatment is surgery. This will work better in less aggressive cancers where all can be removed without excessive damage to the normal brain. Surgery can be supplemented by radiotherapy which is also used to control aggressive disease that is either inoperable or returns after operation.
Special techniques can be used to implant radioactive sources into a tumour to give high local doses to the tumour while sparing the surrounding brain. Stereotactic radiosurgery, which focuses a radiotherapy beam on a small area, may be used to treat small deep-seated cancers. Chemotherapy is important in childhood brain cancers but has limited use in adults. In aggressive cancers that have been treated with surgery and radiotherapy, further control can be achieved with a combination of drugs (e.g. PCV, procarbazine, lomustine and vincristine) but often only for a few months.
The initial symptoms are often controlled with corticosteroid tablets, particularly dexamethasone, which can reduce the brain swelling around the cancer. Drugs to control seizures and symptom control of pain and nausea may also be required.