Effect of genetic cancer risk assessment on surgical decisions at breast cancer diagnosis.

ABSTRACT

HYPOTHESIS: Breast cancer gene (BRCA) mutation status affects patients' surgical decisions when genetic cancer risk assessment is offered at the time of breast cancer diagnosis, prior to definitive treatment. PATIENTS AND INTERVENTIONS: Outcomes following genetic cancer risk assessment were studied for women newly diagnosed as having breast cancer who were prospectively enrolled in an institutional review board-approved hereditary cancer registry during a 1-year sampling frame. BRCA gene analysis was offered to subjects with a calculated mutation probability of 10% or higher. Review of medical records and telephone survey were used to document surgical treatment decisions following genetic cancer risk assessment. RESULTS: Thirty-seven of 233 women in the registry were enrolled at the time of a breast cancer diagnosis. The interval from diagnosis to genetic cancer risk assessment ranged from 3 to 60 days. The mean calculated probability of a BRCA gene mutation was 21% across the cohort. Two women were not tested because of low prior probabilities of mutation detection, and 3 declined owing to intercurrent psychological stressors. Of the remaining 32 patients, no BRCA gene mutation was detected in 22 (69%), 3 (9%) were found to carry a variant of uncertain significance, and 7 (22%) had a deleterious mutation. All 7 subjects with a deleterious mutation opted for bilateral mastectomy, whereas 20 of 22 patients with negative test results chose stage-appropriate treatment (P<.001). CONCLUSIONS: Genetic cancer risk assessment at the time of breast cancer diagnosis significantly affected women's treatment decisions. Although need and feasibility are demonstrated, the logistics of genetic cancer risk assessment during breast cancer diagnosis prove challenging.