Cancer and heredity


Research suggests that some cancers are more likely to occur in some people based on heredity. This is because genes have been shown to play a role in the development of some cancers.

Current knowledge suggests that the strongest hereditary links are with bowel, breast and stomach cancers.

About five to ten per cent of cancers are thought to be hereditary.

However, it is known that the strongest causes of most cancers are environmental factors like tobacco, diet, alcohol, infection, radiation, drugs and chemicals.

Breast cancer and genetics

With almost 2900 cases of breast cancer in Australia each year, it is the most common cancer in Australian women. There are a number of factors that determine a woman’s risk of developing breast cancer, at the forefront of which is age. Ovarian cancer is another substantial risk factor in breast cancer.

About 1 in 20 cases of breast cancer are attributable to hereditary factors.

Bowel cancer and genetics

With almost 3500 cases diagnosed in Australia each year, bowel cancer is the second most common cancer, following prostate cancer. As with breast cancer, the single biggest risk factor is age.

Cancer and family history

If a family has a strong history of cancer, this normally means the same type of cancer has occurred in family members over several generations, or one member was diagnosed at an unusually young age.

Those who are part of these families can be referred to a specialist genetics service, where pathology reports of relatives who have carried cancer are checked and an estimate of the risk of cancer to the person may be provided.

If a person is deemed to be at a higher than average risk of developing cancer, a specialist can arrange screening in order to pick up the signs of cancer as soon as possible.

Cancers believed to have a genetic link

Breast cancer
Bowel cancer
Prostate cancer
Stomach cancer


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