Breast Cancer Risk Perceptions among Relatives of Women with Uninformative Negative BRCA1/2 Test Results: The Moderating Effect of the Amount of Shared Information.

The most common result of BRCA1/2 mutation testing when performed in a family without a previously identified mutation is an uninformative negative test result. Women in these families may have an increased risk for breast cancer because of mutations in non-BRCA breast cancer predisposition genes, including moderate- or low-risk genes, or shared environmental factors. Genetic counselors often encourage counselees to share information with family members, however it is unclear how much information counselees share and the impact that shared information may have on accuracy of risk perception in family members. We evaluated 85 sisters and daughters of women who received uninformative negative BRCA1/2 results. We measured accuracy of risk perception using a latent variable model where accuracy was represented as the correlation between perceived risk (indicators = verbal and quantitative measures) and calculated risk (indicators = Claus and BRCAPRO). Participants who reported more information was shared with them by their sister or mother about her genetic counseling session had greater accuracy of risk perception (0.707, p = 0.000) than those who reported little information was shared (0.326, p = 0.003). However, counselees shared very little information; nearly 20 % of family members reported their sister or mother shared nothing with them about her genetic counseling. Family members were generally not aware of the existence of a genetic counseling summary letter. Our findings underscore the need for effective strategies that facilitate counselees to share information about their genetic counseling sessions. Such communication may help their relatives better understand their cancer risks and enhance risk appropriate cancer prevention.