Weighing up genetic testing for breast cancer

1 April 2011

Breast cancer is the most common form of cancer among women in Australia. While most cases are sporadic, 5–10% of affected women have a strong family history of breast cancer. For most of these women, the cause of breast cancer is unknown, but some women have a mutation in a gene that increases the risk of breast cancer.

Writing in the latest edition of Australian Prescriber, Dr Chiyan Lau and Dr Graeme Suthers of SA Pathology in Adelaide weigh up the pros and cons of genetic testing for breast cancer.

“There are two commonly identified mutations, which together are found in approximately 1–2% of all breast cancers. However, women with familial breast or ovarian cancer should not necessarily undergo genetic testing for these mutations, as the majority do not have these genetic mutations.”

They warn that analysis of these genes is complex and expensive, and is often not justified. Similarly, genetic testing of an unaffected person is generally not recommended unless one of the mutations has already been identified in a family member.

“It’s important that counselling is provided before and after a genetic test, and the care of someone with the mutation is individualised.”

“The absence of an identified mutation in an affected woman does not exclude familial breast cancer. However, once a mutation has been identified in the family, a normal test result means that the person has not inherited the family's predisposition to develop cancer and does not require special cancer surveillance,” they conclude.

To read the full article and more visit www.australianprescriber.com

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Australian Prescriber is an independent peer-reviewed journal providing critical commentary on therapeutic topics for health professionals, particularly doctors in general practice. It is published by NPS, an independent, not-for-profit organisation for quality use of medicines funded by the Australian Government Department of Health and Ageing. Australian Prescriber is published every two months, in hard copy that is distributed to health professionals free of charge, and online in full text at www.australianprescriber.com