Prospective Randomized Biomarker Study Of Metformin And Lifestyle Intervention For Prevention In Obese Postmenopausal Women At Increased Risk For Endometrial Cancer.

1551Background: Obesity significantly increases risk of endometrial cancer (EC) through systemic metabolic effects and local tissue action, driven by estrogen and dysregulated insulin signaling. EC is most commonly diagnosed in postmenopausal women. Metformin, an antidiabetes drug, and lifestyle intervention were evaluated for effects on endometrial proliferation and serum biomarkers, in parallel with weight loss. Methods: Obese postmenopausal women were randomized into 4 groups for a 16 week intervention using a 2 (metformin 1700 mg/day vs placebo) x 2 (lifestyle intervention vs no lifestyle intervention) factorial design based on the Diabetes Prevention Program. Pre- and post-intervention endometrial biopsies were assessed for proliferation (% Ki67+). Body weight and serum markers were measured pre- and post-intervention (estrone, FSH, DHEA-S, SHBG, IGF-1, adiponectin, omentin, insulin, glucose, A1C, ALT, triglycerides, and others). Results: Of 576 women approached for the study, 29 women were randomize...