e13004 Background: BRCA is a hereditary genetic mutation associated with a higher risk of breast cancer at younger age. Generally, BRCA gene testing is done in perceived high-risk individuals, and different management approaches might be considered given the high risk of breast cancer. This study examines treatment outcomes among BRCA-positive, metastatic breast cancer patients with consideration of prophylactic management by using US nationwide EHR data. Methods: This was a retrospective cohort study using Optum EHRs. The study cohort includes female adults who underwent their first systemic chemotherapy for metastatic breast cancer between 2013-2018 with a BRCA positive test result prior to the systemic chemotherapy, with ≥ 6 months baseline period from the chemotherapy. Physicians’ notes captured in Natural Language Processing (NLP) were further used to construct the cohort. Patients were followed from the earliest breast cancer diagnosis date until a censoring event (death or end of observation period). Death information was provided with national death certificate data. Descriptive statistics were used for patient characteristics and a stepwise Cox Proportional Hazard (CPH) regression model was fit to compare survival time. Results: Of 3624 patients included in the cohort, median age at the earliest breast cancer diagnosis is 50 years old (IQR 43-59), and a total of 540 (14.9%) deaths was observed. Prior to systemic chemotherapy, 1430 (39.5%) received mastectomy/lumpsectomy. 571 (15.8%) received hormone therapy prior to systemic chemotherapy. 646 (17.8%) had a clinical record indicating a triple negative breast cancer (TNBC). 2196 (60.6%) received more than 1 line of chemotherapy. Overall median survival days in the study cohort was 3778 days from the earliest breast cancer diagnosis. Median survival days in those with ER/PR positive and with TNBC status were 4150 days and 3124 days, respectively. From the CPH model, age, tumor mutation status, and prior mastectomy/lumpectomy were identified as significant factors; Hazard Ratio (HR) with each 1 year older in age at diagnosis was 1.02 (95% CL 1.01-1.03), that of TNBC vs ER/PR positive status was 2.27 (95% CL 1.87-2.77) and that of those with prior surgery vs without was 0.567 (95% CL 0.457-0.703). Conclusions: This study demonstrated the utility of EHR database for survival analysis. In metastatic breast cancer patients with a known BRCA-positive status, age at the initial diagnosis, tumor mutation status, and prior mastectomy/lumpectomy were significant factors in survival time.
Possibilities of positron emission tomography in the metastatic breast cancer diagnosis
