Points to Consider in Breast and Ovarian Cancer Screening
By Beth A. Pletcher, MD, March 1998

• Only 5-7% of breast and ovarian cancer is related to an inherited gene change. The remaining 93-95% are sporadic.

• Women who have a strong family history of breast and/or ovarian cancer may benefit from genetic testing to redefine their risks and surveillance options.

• Original studies suggested that women who carry a BRCA1 or 2 mutation have up to an 87% lifetime risk for developing breast cancer and BRCA1 carriers have a 32-84% lifetime risk for developing ovarian cancer. Newer studies suggest that penetrance (risks for actually getting cancer) varies significantly from family to family. BRCA2 mutations are found more often in families with cases of male breast cancer.

• Except in the Ashkenazi Jewish population where only a limited number of gene mutations are found, genetic testing requires gene sequencing which is expensive, complex and often difficult to interpret.

• Under most circumstances, the best person to screen for BRCA1 or 2 mutations is an affected individual in the immediate family. Individuals with ovarian cancer at any age or premenopausal breast cancer may be the most informative for other family members at risk.

• Patients with a strong family history who choose not to be tested or whose relatives are not available for testing can still benefit from more intensive surveillance for these cancers.

• A negative DNA test on an unaffected, at-risk family member in the context of a known mutation in an affected family member, is quite informative, may provide some degree of reassurance and may alter surveillance recommendations.

• On the other hand, a negative DNA test in an unaffected, at-risk family member in isolation provides little information or reassurance for that individual since there may be an unidentifiable mutation running in the family.

• A positive test for a predisposition mutation does not confer certainty for developing a malignancy. Prophylactic surgery, while it may decrease cancer risks, does not entirely eliminate the risks for developing cancer and poses inherent post-surgical morbidity.