Real-World Epidemiology, Clinical Characteristics and Outcomes of Women with Germline BRCA Mutation and Early Breast Cancer in China.

INTRODUCTION: The poly(ADP-ribose) polymerase inhibitor olaparib was recently approved in China for adjuvant treatment of certain patients with high-risk, human epidermal growth factor (HER2)-negative early breast cancer (eBC) and germline pathogenic/likely pathogenic mutations in BRCA1 and BRCA2 (gBRCAm). Further evidence on demographics, clinical characteristics, treatment patterns and outcomes is needed to inform local guideline updates and clinical decision-making for patients in China with gBRCAm and eBC who may be eligible for olaparib treatment. METHODS: This retrospective study analysed deidentified electronic health records at the Fudan University Shanghai Cancer Center. Women ≥ 18 years of age diagnosed with eBC between 1 January 2012 and 31 December 2019 who had undergone definitive BC surgery were included. Patients with accessible gBRCA status were included alongside a similar-sized cohort of randomly selected, untested patients. Demographics, clinical characteristics, treatment patterns, pathological complete response (pCR) and invasive disease-free survival (IDFS) were described by tumour subtype and gBRCAm status. RESULTS: In total, 949 patients were included (gBRCA tested: n = 466; untested: n = 483). Among 89/466 (19.1%) tested patients with gBRCAm, 29/89 (32.6%) had no family history of breast/ovarian/pancreatic/prostate cancer, and 46/88 (52.3%) with known tumour subtype had hormone receptor-positive tumours. Patients with HER2-negative eBC and gBRCAm had more advanced disease, differing treatment patterns and shorter IDFS versus those with non-gBRCAm. pCR rates among patients who received neoadjuvant therapy were 23.1% in the overall population (n = 91) and 10.9% in patients with HER2-negative eBC (n = 55), 52 (94.5%) of whom received chemotherapy only. CONCLUSION: Characteristics, treatment patterns and outcomes were distinct among patients in China with gBRCAm eBC. Our findings support wider implementation of gBRCA testing for all patients in China with HER2-negative eBC, beyond those with triple-negative tumour subtype and/or family history of cancer, to identify more patients who may benefit from targeted therapy. Infographic available for this article.