What is cancer?

Cancer is a disease of the body's cells. Our bodies are always making new cells: so we can grow, to replace worn-out cells, or to heal damaged cells after an injury. This process is controlled by certain genes. All cancers are caused by changes to these genes. Changes usually happen during our lifetime, although a small number of people inherit such a change from a parent.

Normally, cells grow and multiply in an orderly way. However, changed genes can cause them to behave abnormally. They may grow into a lump. These lumps can be benign (not cancerous) or malignant (cancerous).

Benign lumps do not spread to other parts of the body.

A malignant lump (more commonly called a malignant tumour) is made up of cancer cells. When it first develops, this malignant tumour is confined to its original site. If these cells are not treated they may spread into surrounding tissue and to other parts of the body.

When these cells reach a new site they may continue to grow and form another tumour at that site. This is called a secondary cancer or metastasis.

For a cancer to grow bigger than the head of a pin, it must grow its own blood vessels. This is called angiogenesis

Can you catch cancer from someone else?

Cancer is not contagious.

You can't catch cancer from someone else.  It is quite safe for you to be with someone who has cancer. An exception is the slight risk posed when someone with cancer is being treated with brachytherapy.

However people receiving normal radiotherapy are not radioactive.

Protect yourself from infections that sometimes can lead to cancer

Find out about what you can do to protect yourself from human papilloma virus (HPV) and hepatitis B. Both of these can cause changes to cells that sometimes lead to cancer.

More on HPV from PapScreen Victoria

There is exciting research going on that is looking at certain other viruses, retroviruses and bacteria which have been linked to some cancers. They include H. pylori, HTLV-1 and Epstein Barr virus.The promise of such research is that preventive vaccines and effective treatments may be developed in the future.

Precautions when someone is having brachytherapy

Brachytherapy is when thin tubes, seeds or rods containing radiaoactive material are put in the body. This sends some radiation outside the body. Because of the slight risk of people being affected by the radiation, the hospital will limit visits while the person is being treated with brachytherapy.

Back to top

This information is currently under review. Updated June 2005