What is brain cancer?

Brain cancers are tumours – abnormal tissue growths – that affect cells in the brain. In the adult brain, few cells divide to produce more cells. Brain tumours occur when something goes wrong with the normal checkpoints and constraints of cell growth, allowing uncontrolled cell division and creating a mass of unwanted cells.

Not all tumours, whether in the brain or elsewhere, are cancerous. Non-cancerous tumours are called benign, meaning that they grow slowly and do not invade neighbouring tissue. Malignant tumours, better known as cancer, grow faster and can spread to nearby tissue or throughout the body.

For diagnostic purposes, brain tumours are graded into ‘stages’ based on their aggressiveness, or how quickly and easily they spread. Benign tumours are grade I; malignant tumours, capable of spreading and therefore considered cancerous, can be grade II, III or IV.

Primary brain tumours originate in brain tissue, while metastatic tumours (those that can spread, or metastasize) are called secondary brain tumours. These metastatic tumours occur when cancerous cells from another tissue travel to the brain and form a tumour. Breast cancer, lung cancer and melanoma are common types of cancer with brain metastasis. The reverse situation – metastasis of a primary brain tumour to another organ – is rare.

Facts and figures of brain cancer

  • More than 1600 Australians are diagnosed with brain cancer each year.
  • More than 1350 Australians die from brain cancer each year. 
  • Only ~20% of patients survive brain cancer (90% survive leukaemia and breast cancer)
  • For very aggressive tumours, such as glioblastoma, only 5% survive
  • Brain cancer kills more children (aged 1-14) in Australia than any other disease
  • Survivors of brain cancer struggle with the side-effects of treatment and their quality of life is impacted, even if the survive a tumour
  • Treatment of brain cancer mostly consists of surgical removal, radiotherapy and chemotherapy
  • We have useful screening tests for breast, cervical, prostate and bowel cancer, but no screening test for the early detection of brain tumours

What causes brain cancer

The causes of brain cancer are not well understood.

Fundamentally, tumours and cancers occur when cells grow and divide uncontrollably. These processes are under the control of various genes: some, called oncogenes, promote growth and cell division; others, called tumour suppressor genes, put the brakes on cell division.

If the DNA in these genes is abnormal (turning on oncogenes, or turning tumour suppressor genes off), tumours can occur. In other words, DNA mutations are the ultimate cause of cancers, including brain cancer.

DNA mutations can be inherited, so a family history of brain cancer presents some risk. However, only a very small proportion of brain tumours are thought to have a hereditary origin, with mutations in tumour suppressor genes increasing the risk for a range of cancers, including those affecting the brain. 

  Types of brain cancer

  Signs and symptoms of brain cancer

  Diagnosing and treating brain cancer

  Brain cancer research at QBI