Supplementary Material for: Case Report of Complete Response to Olaparib in a Patient with Breast Cancer Brain Metastases

Introduction: Breast cancer is the second most common cause of central nervous system (CNS) metastases. It has been shown that the median time from breast cancer diagnosis to CNS metastasis is 30.9 months and that the overall median survival after metastasis is extremely poor at 6.8 months. Although treatment options for Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2)-positive breast cancer brain metastasis (BCBM) have been reported, effective treatment options for ERBB2-negative BCBM, which has one of the worst prognoses, are limited. Olaparib is one of the standard treatments for germline BRCA1/2 mutated (gBRCA1/2mt), ERBB2-negative, metastatic, or recurrent breast cancer. However, there is minimal existing evidence to evaluate the efficacy of olaparib in BCBM. Case: In our report, we assessed the case of a Japanese woman in her early 30s, ERBB2-negative, gBRAC2mt-positive BCBM, who achieved a complete response (CR) and prolonged progression-free survival (PFS) of nine months after the initiation of treatment with olaparib. Conclusions: Thus, our case report demonstrated the significant efficacy of olaparib in BCBM treatment. Furthermore, we highlighted the need for more studies to investigate the efficacy of olaparib and explore the efficacy of poly ADP ribose polymerase (PARP)-inhibitors in BCBM.

引言：乳腺癌是中枢神经系统（central nervous system，CNS）转移瘤的第二大常见原发癌。研究表明，从乳腺癌确诊至发生中枢神经系统转移的中位时间为30.9个月，而转移发生后的总体中位生存期仅为6.8个月，预后极差。尽管已有针对表皮生长因子受体2（Erb-B2 Receptor Tyrosine Kinase 2，ERBB2）阳性乳腺癌脑转移（breast cancer brain metastasis，BCBM）的治疗方案，但预后极差的ERBB2阴性乳腺癌脑转移的有效治疗手段仍十分有限。奥拉帕利（olaparib）是种系BRCA1/2突变（germline BRCA1/2 mutated，gBRCA1/2mt）、ERBB2阴性的转移性或复发性乳腺癌的标准治疗方案之一，但目前针对奥拉帕利在乳腺癌脑转移中疗效的相关研究证据极少。病例：本病例报告评估了1例30岁出头的日本女性患者，其确诊为ERBB2阴性、gBRAC2mt阳性的乳腺癌脑转移，经奥拉帕利治疗后达到完全缓解（complete response，CR），且无进展生存期（progression-free survival，PFS）延长至9个月。结论：综上，本病例报告证实了奥拉帕利在乳腺癌脑转移治疗中的显著疗效。此外，本研究强调需开展更多研究以评估奥拉帕利的疗效，并探索多聚ADP核糖聚合酶（poly ADP ribose polymerase，PARP）抑制剂在乳腺癌脑转移中的应用价值。