Survival outcomes of BRCA1/BRCA2 mutated breast cancers: Study from a tertiary care cancer centre in India.

Abstract

e22546 Background: There exists a discrepancy amongst various studies over the years on survival outcomes of BRCA (Breast cancer susceptibility gene) mutated breast cancers. Prevalence of BRCA mutation varies from 10 to 18% among Indian population and there is a paucity of data on the survival outcomes of this population. Methods: This ambispective observational study assessed the survival outcomes of 71 BRCA mutated breast cancer patients, treated with uniform protocol at AIIMS New Delhi between January 2014 to December 2022, using survival analysis and cox regression methods. Results: Amongst the 71 patients, BRCA1 and BRCA2 mutated cases were 52 (73.2%) and 19 (26.8%) respectively. The median age was 39 years (24-63 years) in both the groups. Positive family history for malignancy (BRCA1- 69.2% vs BRCA2- 36.8%) and incidence of Triple negative histology (BRCA1-82.7% VS 36.8%) were more commonly associated with BRCA1 positivity. Eight patients (11.3%) had synchronous cancer, most common being a contralateral breast primary. 4 patients (5.6%) developed metachronous cancer. Eighty percent of patients were premenopausal at presentation. There was no difference in stage at presentation, incidence of synchronous and metachronous cancers across both the groups. Of 71 patients, 18 (25%) and 17 (24%) patients underwent risk reducing mastectomy and risk reducing oophorectomy respectively. Thirty five (49.3%) presented with stage I & II disease, while 28 (34.4%) and 7 (9.9%) presented with stage III and metastatic disease respectively. Forty seven patients (67.1%) received neoadjuvant chemotherapy with pathologic complete response rate of 42.5% which was uniform among both the groups. Over the study period, 10 (14.1%) patients had disease relapse with 7 (70%) being metastatic and 3 patients died of the disease. With a median follow up of 36.9 months, 3-year disease free survival (DFS) was 84.2% (BRCA1: 81.1% vs BRCA2: 93.1%) and overall survival (OS) was 94.7% for both groups. Median DFS and OS were not achieved. BRCA type, receptor status, age and menopausal status were not predictors of survival in our study. Conclusions: In our study population of BRCA1/BRCA2 mutated breast cancer, survival outcomes were comparable to historical cohorts of Indian breast cancer patients. Thus, BRCA mutation positivity doesn’t seem to have any prognostic significance in breast cancer outcome.