Abstract B17: Type 2 diabetes, metformin, and ovarian cancer survival: An analysis of tumor registry and electronic medical record data.

Abstract

Abstract Background: Type 2 Diabetes Mellitus (T2D) is associated with increased cancer risk and higher cancer mortality. Metformin, a common T2D treatment, is associated with improved survival for several cancers. With a five year survival of 42%, repurposing metformin to improve ovarian cancer prognosis is attractive. However, only a few studies to date have evaluated associations between T2D, metformin use, and ovarian cancer survival. Methods: We evaluated tumor registry confirmed ovarian and fallopian tube cancer cases from the Vanderbilt University Medical Center. Metformin use was determined from electronic medical records (EMR) using MedEx. For validation, natural language processing EMR review was conducted for 50 subjects. Cox proportional hazards regression was used to evaluate associations with overall survival and calculate Hazard Ratios (HR) and corresponding 95% Confidence Intervals (CI); models included adjustment for age, stage, histologic subtype, and body-mass index (BMI). Results: Tumor registry data and EMR was available for 372 invasive epithelial ovarian cancer cases. Forty (10.8%) had T2D, and 20 had metformin use (5.4%). MedEx and EMR reviewed metformin use was highly concordant (Kappa=0.96). Associations with overall survival were suggestive but non-significant for T2D (HR: 0.80, 95% CI: 0.51-1.25) and metformin use, either among only T2D cases (HR: 0.73, 95% CI: 0.29-1.84) or among all ovarian cancer cases (HR: 0.61, 95% CI: 0.31-1.21). Two or more years of metformin use was significantly associated with better survival compared to cases without metformin use (HR: 0.28, 95% CI: 0.09-0.89). Exploratory analyses suggested better survival among serous cases and worse survival among non-serous cases for both T2D and metformin, but associations were not significant. Analyses to address survival time bias yielded results comparable to our primary findings. Conclusions: Ovarian cancer cases with metformin use had marginally better overall survival. While not significant, these associations indicate that metformin may have utility repurposed as a treatment for ovarian cancer. Larger studies are needed to determine if associations differ by histology, and if metformin may be beneficial to all ovarian cancer subtypes. Citation Format: Spencer Keene, Samantha P. Stansel, Leshaun Clayton, Min Jiang, Melinda Aldrich, Hua Xu, Jeremy Warner, Joshua Denny, Dineo Khabele, Alicia Beeghly-Fadiel. Type 2 diabetes, metformin, and ovarian cancer survival: An analysis of tumor registry and electronic medical record data. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr B17.