Impact of BRCA1/BRCA2 counseling and testing on newly diagnosed breast cancer patients.

Objective: Approximately 5% to 10% of newly diagnosed breast cancer patients carry a BRCA1 or BRCA2 mutation. Given these patients' high risk for contralateral breast cancer, bilateral mastectomy is increasingly considered a treatment option for newly diagnosed BRCA1/2 carriers. In the present study, we prospectively evaluated the impact on surgical decision-making of pretreatment genetic counseling and BRCA1/BRCA2 testing among breast cancer patients at high-risk for carrying a mutation.

Methods: Participants were 194 newly diagnosed breast cancer patients who had not yet received definitive surgical treatment and who had at least a 10% prior probability of carrying a BRCA1/2 mutation. Participants were offered free genetic counseling and rapid BRCA1/2 testing. Primary analyses focused on the impact of BRCA1/2 test result on subsequent breast cancer surgical treatment.

Results: Forty-eight percent of patients who were found to carry a BRCA1/2 mutation chose bilateral mastectomy as their definitive breast cancer surgery. In contrast, 24% of patients in whom no mutation was detected and 4% of test decliners opted for bilateral mastectomy. Additional predictors of bilateral mastectomy included patients' self-reports of physician recommendations for BRCA1/2 testing and bilateral mastectomy.

Conclusions: This study highlights patient interest in and the technical feasibility of offering presurgery BRCA1/2 testing to high-risk patients. Most importantly, these results demonstrate that BRCA1/2 test results significantly affect patients' surgical decision-making. The availability of genetic counseling and testing could serve as a valuable aid to patient decision-making for newly diagnosed breast cancer patients at high-risk for carrying a mutation.