Familial breast and ovarian cancer
To identify patients who may be at risk of familial breast and ovarian cancer, a comprehensive family history must be taken and regularly updated.
Refer individuals and families who meet high-risk criteria to a family cancer clinic.
Women who are at average or only slightly higher risk of familial breast and ovarian cancer do not require additional surveillance beyond the National Breast Cancer Screening Program and National Cervical Screening Program nor referral to a family cancer clinic.
What do I need to know?
Highly in BRCA1 and BRCA2 genes are associated with increased risk of several cancers, particularly breast and ovarian. These show pattern. in BRCA1 and BRCA2 are associated with increased risk of other cancers including prostate cancer and pancreatic cancer.
The lifetime risk of breast cancer in Australian women is approximately one in eight. Pathogenic variants of the BRCA1 and BRCA2 genes increase the chance of developing breast cancer to about 70% (cumulative risk to 80 years of age). Despite this, BRCA1 and BRCA2 variants account for only about 5% of all breast cancer cases, because these variants are relatively rare.
Several other genes (low-to-moderate penetrant variants) predisposing to breast and/or ovarian cancer can now also be tested. Features within a family that are suggestive of increased risk of having a pathogenic BRCA1 or BRCA2 variant include:
- multiple affected relatives on the same side of the family (maternal or paternal)
- breast and ovarian cancer in the same woman
- breast cancer diagnosed <40 years of age
- Ashkenazi Jewish ancestry (from central and eastern Europe)
- bilateral breast cancer
- male breast cancer
A three-generation family history is key to identifying high-risk families who are most likely to benefit from genetic testing. Such a history should include first-degree and second-degree relatives on both sides of the family, and ethnic background (eg Ashkenazi Jewish). Note that sex-specific cancer can be inherited through maternal or paternal sides of the family (eg BRCA variants can be passed from the paternal side). Type of cancer (including bilateral) and age of onset should be recorded where available.
Use existing risk criteria to identify families who are at increased risk of having a pathogenic BRCA1 or BRCA2 variant (high risk), or women who may require additional screening or chemoprevention (moderately increased risk).
Family cancer clinics can assess individual risk to determine the utility of genetic testing for BRCA1 and BRCA2 variants. As new genes in which variants predisposing to breast cancer are identified, testing of these genes may be offered as part of a panel of genetic tests through the family cancer clinic. If a pathogenic variant is identified in an individual, testing will be offered to relatives.
A range of options are available to carriers of BRCA1 and BRCA2 variants to manage their increased cancer risks.
A rebate is available for BRCA1 and BRCA2 gene testing under the Medicare Benefits Schedule (MBS).
Validated polygenic risk scores (PRS) for breast cancer are commercially available. In combination with other known risk factors (e.g. family history, lifestyle and hormonal risks) PRS may be used to provide individualised information about breast cancer risk. Their precise role in risk-based breast cancer prevention and screening in Australia is yet to be determined.
When should I refer?
The recommended breast cancer screening strategy for women and individuals at increased risk of breast cancer is outlined in the Royal Australian College of General Practitioners (RACGP’s) 2016 Guidelines for preventive activities in general practice (Red Book).
A cancer antigen 125 (CA 125) blood test and transvaginal ultrasound are not recommended as screening tests for ovarian cancer, even in women who are at high risk as such screening has not been shown to improve prognosis.
Women at increased risk for breast and ovarian cancer should be encouraged to:
- discuss their family history with all first-degree relatives
- advise family members to discuss their risk with their general practitioner (GP).
- Dunlop K, Kirk J, Tucker In the wake of Angelina: Managing a family history of breast cancer. Aust Fam Physician 2014;43(1):76–78. [Accessed 6 September 2022].
- The Royal Australian College of General Practitioners Guidelines for preventive activities in general practice. 9th edn. Melbourne, RACGP, 2016. [Accessed 6 September 2022].
- National Cancer Institute (US). BRCA1 and BRCA2: Cancer risk and genetic Bethesda, MD: National Institutes of Health, 2015. [Accessed 6 September 2022].
- Cancer Australia. Advice about familial aspects of breast cancer and epithelial ovarian cancer: A guide for health Sydney: Cancer Australia, 2010. [Accessed 6 September 2022].
- Kuchenbaecker KB, Hopper JL, Barnes DR, et Risks of breast, ovarian, and contralateral breast cancer for BRCA1
- and BRCA2 mutation carriers. JAMA 2017;317(23):2402–16.
- Cancer Australia. Recommendations for the management of early breast cancer in women with an identified BRCA1 or BRCA2 gene mutation or at high risk of a gene mutation.
- Winship I, Southey Gene panel testing for hereditary breast cancer. Med J Aust 2016;204(5):188–90.
- Department of Medicare Benefits Schedule. Canberra: DoH, 20227. [Accessed 14 February 2022].
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