[The long-term efficacy of metformin in megestrol acetate-based fertility-sparing treatment for patients with endometrial atypical hyperplasia and endometrioid endometrial cancer].

ABSTRACT

Objective: To assess the long-term efficacy of metformin in megestrol acetate (MA)-based fertility-sparing treatment for patients with endometrial atypical hyperplasia (EAH) and endometrioid endometrial cancer (EEC). Methods: The randomized controlled trail study was conducted from October 2013 to October 2017 in the Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China. Patients with EAH or EEC were firstly stratified according to pathology, and randomized to receive MA (160 mg orally, daily) plus metformin (500 mg orally, three times a day) or MA (160 mg orally, daily). Baseline data between two groups of patients were compared. Estimates of time to complete remission (CR) and recurrence-free survival (RFS) were calculated using the Kaplan-Meier method. Cox proportional-hazards regression model was used to estimate hazard ratios (HR) of related factors for recurrence-free survival. Quantitative data were represented by M (Q1, Q3). Results: A total of 150 patients were included, and 76 patients were allocated to receive MA plus metformin with the age of 32.5 (28.0, 36.0), while 74 patients received MA alone with the age of 32.0 (28.0, 36.0). By the end of follow-up period, 96.7% (n=145) of patients achieved complete remission, with a median follow-up time of 57.7 (26.7, 70.5) months. The median CR time for the MA plus metformin group and the MA alone group were 6.3 (3.5, 8.3) months and 6.8 (4.0, 9.3) months, respectively (P=0.193), with 2-year cumulative CR rate of 98.6% and 98.5%, respectively (P=0.879). The median time of RFS was 28.1 (12.5, 57.3) months for the MA plus metformin group and 33.3 (14.1, 62.5) months for the MA alone group (P=0.213), with a cumulative RFS rate of 61.9% and 65.8%, respectively (P=0.560). In the subgroup of non-obese (body mass index<28 kg/m2) patients with EAH, the median RFS times were 25.7 (7.6, 60.3) months and 47.3 (17.5, 64.8) months for the MA plus metformin group and the MA alone group, respectively (P=0.033), with a cumulative RFS rate of 57.5% and 80.6%, respectively (P=0.029). According to Cox proportional hazards regression analysis, undergoing assisted reproductive treatment (HR=2.358, 95%CI 1.069-5.204, P=0.034) was identified as an independent risk factor for recurrence-free survival after complete remission of endometrial lesions. Conclusion: The long-term follow-up outcome indicates that there is no significant difference in CR time and RFS time between MA plus metformin therapy and MA alone therapy for patients with EAH or EEC.