A family history can identify potential carriers of BRCA mutations who should be offered genetic counselling
Look for families with multiple cases of breast cancer or at least two relatives on the same side of the family (maternal or paternal) who had breast cancer before 50 years of age, or any case of ovarian cancer, bilateral breast cancer or breast cancer in a man.1 Breast cancer before 60 years of age in women of Ashkenazi Jewish descent also suggests increased risk.1 If the criteria for genetic testing are met,1 family members who have had cancer are tested first. If a BRCA1 or BRCA2 mutation is found, testing can be offered to unaffected relatives. Criteria for genetic testing vary across Canada — consult your local genetics clinic.
BRCA1 and BRCA2 mutations increase the risk of breast and ovarian cancers
Table 12–4 outlines the predicted cumulative risk of cancer in the general population and among male and female carriers of BRCA mutations.
Referral to a genetics clinic will clarify risk and management
These clinics perform a personalized risk assessment using a detailed family history of cancer. Families who meet criteria for genetic testing will receive a full discussion of its benefits, risks and limitations. People who are not at high risk, either because they do not meet the criteria for testing or because their tests were negative for a known family mutation, can be reassured. People who have a BRCA mutation, or who are at high risk based on family history but have an uninformative test result, will receive management recommendations. Women with a lifetime risk of breast cancer greater than 20%–25% should be offered annual screening with magnetic resonance imaging (MRI) and mammography.5
Clinical interventions for carriers of a BRCA mutation can save lives
Women who have BRCA mutations may choose bilateral mastectomy (for > 90% reduction in the incidence of breast cancer)1,5 or annual screening with MRI and mammography from age 25–30 years,5,6 with or without chemoprevention.6 All women who opt for a risk-reducing mastectomy should be offered immediate or delayed breast reconstruction. There is no effective screening for ovarian cancer, but bilateral salpingo-oophorectomy before menopause, after childbearing is completed, will almost eliminate the risk of ovarian cancer and will reduce the risk of breast cancer by 50%.7
Resources on family history and risk are available for patients and health care professionals
Appendix 1 (available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.111670/-/DC1) outlines several on-line resources.
Footnotes
For references, please see Appendix 2, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.111670/-/DC1
Competing interests: Ellen Warner has consulted for Bayer Schering Pharma; she has received grant funding from Amersham Health. No other competing interests were declared.
This article has been peer reviewed.