RT Journal Article SR Electronic T1 478 Overall survival associated with BRCA or ATM mutation status in patients with ovarian cancer: findings from the PRIOR-2 study JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A239 OP A240 DO 10.1136/ijgc-2021-ESGO.410 VO 31 IS Suppl 3 A1 G Adeboyeje A1 M Sierra A1 A Bartels A1 M Field A1 S Jhamb A1 A Buikema A1 S Joo YR 2021 UL http://ijgc.bmj.com/content/31/Suppl_3/A239.3.abstract AB Introduction/Background*Many clinical guidelines recommend patients with ovarian cancer (OC) undergo mutational testing of genes involved in DNA damage repair response as a predictive marker of clinical benefit from platinum-based chemotherapy and targeted therapies. However, there is little known on the prognostic impact of BRCA or ATM mutation on the survival experience of OC patients receiving contemporary routine care in the United States.Methodology In this retrospective cohort study, we identified patients aged ≥18 years with OC (≥2 OC diagnoses within 90 days) in Optum’s de-identified electronic health record (EHR) database (1/1/2017 – 6/30/2020; N=16.6M total female lives). Index date was the first diagnosis of OC. Patients were stratified by BRCA/ATM status and followed for up to 24 months to assess overall survival (OS). Death was captured from the EHR and linked social security and obituary data. Two-year OS rates were evaluated using the Cox Proportional-Hazards model, adjusting for baseline demographics, comorbidities, clinical and prognostic factors.Result(s)*Among 11,206 patients with OC, 1,901 (17.0%) had evidence of being tested for BRCA/ATM: 616 (32.4%) had BRCA/ATM mutation, 682 (35.9%) did not BRCA/ATM mutation, and 603 (31.7%) had unknown status. Patients with BRCA/ATM mutation had a mean age (SD) 59.5 (10.9) and 62.2 (12.1) years, respectively; 35.9% of patients with BRCA/ATM mutation had visceral metastasis at diagnosis compared with 31.8% with no mutation. Of patients with known stage at diagnosis and with BRCA/ATM mutation (N=416), 77.2% presented at stage 3/4 compared with 70.6% of patients without BRCA/ATM mutation (N=503). Patients with BRCA/ATM mutation and no BRCA/ATM mutation were observed for a median of 705 days and 697 days, respectively. Two-year OS rates were not significantly different by BRCA/ATM mutation status (yes: 79.2% vs no: 75.4%, p=0.13); unadjusted hazard ratio (HR) 1.22 (95% CI =0.94–1.58); adjusted HR 1.12 (95% CI 0.85–1.47).Conclusion*In this observational study of US patients with ovarian cancer, there was no statistically significant difference in two-year OS rates between patients with or without BRCA/ATM mutation. Additional research is needed to evaluate the association between BRCA/ATM status and overall survival in different patient populations.