Effect on perceived control and psychological distress of genetic knowledge in women with breast cancer receiving a BRCA1/2 test result.

Information provision during BRCA1/2 genetic counseling is complex and expected to be increasingly so with gene panel testing. This prospective study evaluated whether genetic knowledge in counselees with breast cancer (BC) after a pre-test genetic counseling visit (T1) enhance their feeling of personal control while minimizing distress after the notification of BRCA1/2 result (T2). At T1, 243 (89% response rate) counselees completed questionnaires on genetic knowledge (BGKQ), perceived cancer genetic risk; of which, at T2, 180 (66%) completed the BGKQ again, scales of anxiety/depression, distress specific to genetic risk, and perceived control. Multilevel models were performed accounting for clinician, and testing an effect of knowledge on psychological outcomes according to the adequacy of counselees' perceived genetic predisposition to cancer. The mean knowledge score was moderate at T1, decreased while not significantly differing by BRCA1/2 test result at T2. Knowledge at T1 had no direct effect on psychological outcomes, but in counselees who over-estimated their cancer genetic risk, higher knowledge at T1 predicted higher specific distress at T2. In BC affected counselees who over-estimate their cancer genetic risk, higher BRCA1/2 pre-test genetic knowledge seem to lead to increased specific distress. Identifying these BC affected counselees who over-estimate their genetic cancer risk and helping them to interpret their genetic knowledge instead of providing them with exhaustive genetic information could minimize their distress after test result receipt.