Evaluation of contralateral breast cancer risk factors in breast cancer patients with BRCA pathogenic variants

Abstract

　In this study, 45 Japanese breast cancer (BC) patients with BRCA1 or BRCA2 pathogenic variants (PVs) were divided into two groups; 10 patients with contralateral breast cancer (CBC) and 35 patients without CBC, and the clinicopathological characteristics of the two groups were compared to evaluate risk factors for developing CBC. The median follow-up after initial surgery for initial BC was 7.4 years, and the median time from the initial surgery to the diagnosis of CBC was 8.1 years. Patients with CBC were significantly younger at the initial BC, had lower rate of receiving chemotherapy for the initial BC, and had lower rate of receiving risk reducing salpingo-oophorectomy (RRSO) than patients without CBC. Patients with CBC also tended to have higher rate of premenopausal status at the initial BC and higher rate of no endocrine therapy for estrogen receptor-positive initial BC. Age at the initial BC, systemic therapy for the initial BC, and RRSO may be associated with CBC in Japanese BC patients with BRCA PVs. It is important to develop a CBC risk assessment model to allow patients to make choices according to their CBC risk, rather than recommending contralateral risk reducing mastectomy to all BC patients with BRCA PVs.