To assess the efficacy of metformin in megestrol acetate (MA)‐based fertility‐sparing treatment for patients with atypical endometrial hyperplasia (AEH) and endometrioid endometrial cancer (EEC).
A randomised, single‐centre, open‐label, controlled trial conducted between October 2013 and December 2017.
Shanghai OBGYN Hospital of Fudan University, China.
A total of 150 patients (18–45 years old) with primary AEH or well‐differentiated EEC were randomised into an MA group (n = 74) and an MA plus metformin group (n = 76).
Patients with AEH or EEC were firstly stratified, then randomised to receive MA (160 mg orally, daily) or MA (160 mg orally, daily) plus metformin (500 mg orally, three times a day).
The primary efficacy parameter was the cumulate complete response (CR) rate within 16 weeks of treatment (16w‐CR rate); the secondary efficacy parameters were 30w‐CR rate and adverse events.
The 16w‐CR rate was higher in the metformin plus MA group than in the MA‐only group (34.3 versus 20.7%, odds ratio [OR] 2.0, 95% confidence interval [CI] 0.89–4.51, P = 0.09) but the difference was more significant in 102 AEH patients (39.6 versus 20.4%, OR 2.56, 95% CI 1.06–6.21, P = 0.04). This effect of metformin was also significant in non‐obese (51.4 versus 24.3%, OR 3.28, 95% CI 1.22–8.84, P = 0.02) and insulin‐sensitive (54.8 versus 28.6%, OR 3.04, 95% CI 1.03–8.97, P = 0.04) subgroups of AEH women. No significant result was found in secondary endpoints.
As a fertility‐sparing treatment, metformin plus MA was associated with a higher early CR rate compared with MA alone in AEH patients.
For AEH patients, metformin plus MA might be a better fertility‐sparing treatment to achieve a higher early CR rate compared with MA alone.