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FAMILIAL BREAST CANCER

What is a family history of breast cancer?

A family history of breast cancer means having a first-degree relative who had or has a diagnosis of breast cancer. The relative can be from the father’s or mother’s side of the family.

Since breast cancer is the most commonly diagnosed cancer in Australia, many women will have a family history by chance. However, sometimes there is a specific genetic variation (or mutation in a gene), that is inherited from one parent that increases the risk of breast cancer. Only about 5-10% of breast cancer cases can be explained by an inherited mutation. There are some factors that may indicate an inherited mutation, for example in families where there are multiple first-degree relatives who have been diagnosed with breast cancer. Familial breast cancer is the term used to describe families with a cluster of breast cancer diagnoses.

family history

Faulty genes linked to increased breast cancer risk

Rarely, faulty (or mutated) genes can be inherited (passed from parent to child). Mutations in the BRCA1 and BRCA2 genes are well-known to be linked to an increased breast cancer risk. However, there may be other genes, or certain combinations of genes, which may increase breast cancer risk when mutated.

BRCA1 and BRCA2 genes

Mutations in the BRCA1 and BRCA2 genes are associated with an increased risk of breast and ovarian cancer. BRCA1 and BRCA2 mutations are considered rare to very rare. About 1 in 400 to 1 in 800 people have a BRCA1 or BRCA2 gene . However, the frequency of BRCA1 and BRCA2 mutations is higher among certain ethnic groups. For example, in Australia about 2.5% of the Ashkenazi Jewish population carry mutations in the BRCA1 and BRCA2 genes compared to less than 1% in the general population. The gene mutations can be passed on both the mother and father’s side of the family.

Over her lifetime, a woman who carries a mutation in one of these genes has about 70% chance of developing breast cancer. However, not everyone who has a faulty BRCA1 or BRCA2 gene will develop cancer. Only about 5-10% of female breast cancers can be explained by inherited mutations.

DNA

What can you do? Managing your breast cancer risk

  • Being breast aware. Women of all ages are encouraged to be aware of how their breasts normally look and feel. If you notice any new or unusual changes, please contact your doctor without delay.
  • Participating in breast cancer screening. Free routine mammographic screening is available in each state for women aged 50-74 through BreastScreen Australia. Women aged 40-49, or over 75, are also entitled to a free mammogram, however, they receive no reminder prompts, like women aged 50-74 do. Book online or contact BreastScreen Australia on 13 20 50.
  • If you have family history or you are concerned that you may have an increased risk of breast cancer, talk to your GP or local family cancer clinic,. Your doctor can help you assess your risk and refer you for additional genetic testing if required.

how to check for breast cancer symptoms

iPREVENT

To help all Australians to know and manage their personal breast cancer risk, NBCF has funded the innovative work of Professor Kelly-Anne Phillips. Her development of web-based tool, iPrevent, was designed help all Australian women to estimate their risk of developing breast cancer so they can take appropriate action. This tool will also help to determine the significance of your family history, amongst other risk factors, to your breast cancer risk.

Try iPREVENT online today

Support services

If you or your loved one is affected by cancer, Cancer Council and Breast Cancer Network Australia have further resources to provide emotional and practical support. Cancer Australia also has further information on managing the physical and emotional changes following cancer, and finding support for those impacted by cancer.

Research into familial breast cancer

NBCF supports a wide spectrum of research, including research to understand, manage and prevent familial breast cancer in men, women and their families. Learn more about our funded researchers and their projects related to familial breast cancer below.