This study aimed to clarify the breast cancer prognosis in Japanese patients with BRCA1/2 pathogenic variant. We analyzed 2235 women with breast cancer who underwent BRCA1/2 genetic testing between 1996 and 2018 using data from the Japanese hereditary breast and ovarian cancer syndrome registry. The cumulative risk for contralateral and ipsilateral breast cancers and time to death since the first breast cancer were stratified based on the BRCA1/2 variant status. The median follow-up was 3.0 years (0.1–34.1 years) after the first breast cancer. The annual average risks of contralateral breast cancer in BRCA1 and BRCA2 and non-BRCA1/2 pathogenic variant carriers were 4.0%, 2.9%, and 1.9%, respectively (P = 0.001). The annual average risks of ipsilateral breast cancer in the three groups were 2.7%, 1.4%, and 1.1%, respectively (P = 0.06). BRCA1 pathogenic variant carriers had significantly higher risks of contralateral (hazard ratio 1.91, P < 0.001) and ipsilateral (hazard ratio 2.00, P = 0.02) breast cancers than non-BRCA1/2 pathogenic variant carriers. The time to death by the BRCA1/2 variant status was not significantly difference (P = 0.28). The prognosis of breast cancer patients who received standard treatment was comparable regardless of the BRCA1/2 variant status.

本研究旨在阐明日本BRCA1/2致病性变异患者的乳腺癌预后。我们使用日本遗传性乳腺癌和卵巢癌综合征登记处的数据分析了 1996 年至 2018 年间接受BRCA1/2基因检测的2235 名乳腺癌女性。对侧和同侧乳腺癌的累积风险和自第一次乳腺癌以来的死亡时间根据BRCA1/2变异状态进行分层。中位随访时间为第一次乳腺癌后 3.0 年（0.1-34.1 年）。BRCA1和BRCA2和非BRCA1/2对侧乳腺癌的年平均风险致病性变异携带者分别为 4.0%、2.9% 和 1.9%（P  = 0.001）。三组患同侧乳腺癌的年平均风险分别为2.7%、1.4%和1.1%（P  = 0.06）。BRCA1致病性变异携带者患对侧（风险比 1.91，P  < 0.001）和同侧（风险比 2.00，P  = 0.02）乳腺癌的风险显着高于非BRCA1/2致病性变异携带者。BRCA1/2变异状态的死亡时间没有显着差异（P  = 0.28）。接受标准治疗的乳腺癌患者的预后是可比的BRCA1/2变体状态。