Brain cancer

Brain cancer

Brain cancers include primary brain tumours, which start in the brain and almost never spread to other parts of the body, and secondary tumours (or metastases), which are caused by cancers that began in another part of the body.

There are more than 40 major types of brain tumours, which are grouped into two main types: 

benign and malignant. Benign tumours are slow-growing and unlikely to spread. Common types are meningiomas, neuromas, pituitary tumours and cranio-pharyngiomas. Malignant tumours are cancerous and able to spread into other parts of the brain or spinal cord. Common types include astrocytomas, oligodendrogliomas, ependymomas, glioblastomas and mixed gliomas.

Incidence and mortality

In 2011, 1,724 brain cancers were diagnosed in Australia. The risk of being diagnosed with a brain cancer by age 85 is 1 in 96 for men and 1 in 149 for women.

In 2012, there were 1241 deaths in Australia caused by brain cancer.

Screening

There is no routine screening test for brain cancer.

Symptoms and diagnosis

Headaches are often the first symptom of a brain tumour. The headaches can be mild, severe, persistent, or come and go.

Other symptoms include:

difficulty speaking, or remembering words

disturbed vision, hearing, smell or taste

seizures: severe (eg. a convulsion) or mild (as in a fleeting disturbance of awareness, sensation or jerking muscles)

weakness or paralysis in part of the body

loss of balance

general irritability, drowsiness or a change in personality

nausea and vomiting.

 If a brain tumour is suspected, the doctor may check how different parts of the brain are functioning by checking the patient’s reflexes, muscle strength, ability to feel pin-pricks and to distinguish between hot and cold. An opthalmoscope is used to view the optic nerve, which may bulge if the pressure in the skull is raised, for example by a tumour.

Diagnosis is usually by MRI and CT scans.

Other tests that are sometimes used are:

angiogram

magnetic resonance spectroscopy

PET scan

single photon emission CT scan

lumbar puncture (also known as spinal tap).

Staging

MRI and CT scans and other tests (see above), if used, determine the extent of the cancer (its stage).

Brain tumours are usually graded on a scale of I to IV, based on how quickly they are growing and their ability to invade nearby tissue:  grades I and II are the slowest growing and are called low-grade tumours; grade IV is the fastest growing.

Causes

The causes of brain tumours are not known. Some brain and spinal cord tumours are more common in people with certain inherited or genetic conditions, and people exposed to very high doses of radiation.

Prevention

There are no proven measures to prevent brain cancer.

Treatment

Brain tumours may be treated with surgery, radiotherapy, chemotherapy or steroid therapy, or a combination of these treatments.

Some tumours can be removed completely by surgery (craniotomy). Post-operative radiotherapy improves local control and survival. For glioblastomas, temozolomide may be added during or after radiotherapy to further improve outcomes.

If a tumour cannot be removed, the aim of treatment is to slow growth and relieve symptoms by shrinking the tumour and any swelling around it. Treatment options include radiotherapy with or without temozolomide.

Prognosis

An individual's prognosis depends on the type and stage of cancer, as well as their age and general health at the time of diagnosis. For benign tumours that can be completely removed, cure is likely. For malignant tumours, outcomes depend on how slowly or quickly the tumour develops and response to treatment. Across all brain cancers, the five year survival rate in Australia is 22%.