Long-term outcomes of progestin plus metformin as a fertility-sparing treatment for atypical endometrial hyperplasia and endometrial cancer patients

Objective: The present study investigated long-term outcomes of medroxyprogesterone acetate (MPA) plus metformin therapy in terms of control of atypical endometrial hyperplasia (AEH) and endometrial cancer (EC), and post-treatment conception. Methods: We retrospectively analyzed 63 patients (42 with EC; 21 with AEH) who underwent fertility-sparing management using MPA plus metformin. MPA (400 mg/day) and metformin (750–2,250 mg/day) were administered to achieve complete response (CR). Metformin was administered until conception, even after MPA discontinuation. Results: Of the total patients, 48 (76%) had a body mass index (BMI) ≥25 kg/m² and 43 (68%) showed insulin resistance. Sixty-one patients (97%) achieved CR within 18 months. CR rates at 6, 8–9, and 12 months were 60%, 84%, and 90%, respectively. During a median follow-up period of 57 months (range, 13–115 months), relapse occurred in 8 of 61 patients (13.1%) who had achieved CR. Relapse-free survival (RFS) in all patients at 5 years was 84.8%. Upon univariate analysis, patients with BMI ≥25 kg/m² had significantly better prognoses than did those with BMI <25 kg/m² (odds ratio=0.19; 95% confidence interval=0.05–0.66; p=0.009). Overall pregnancy and live birth rates per patient were 61% (19/31) and 45% (14/31), respectively. Conclusions: MPA plus metformin is efficacious in terms of RFS and post treatment conception. Moreover, metformin may be more efficacious for patients with BMI ≥25 kg/m².