Antiproliferative Effect of Metformin on the Endometrium - a Clinical Trial

Background: Unopposed estrogen has a central role in development of endometrial benign, premalignant andmalignant lesions. The aim of this study was to evaluate the anti-estrogenic effect of metformin on endometrialhistology in comparison with progesterone. Materials and
Methods: A total of 43 patients who were referredto our center for abnormal uterine bleeding and had a histologic diagnosis were disordered proliferativeendometrium or simple endometrial hyperplasia were included and randomly distributed in two groups treatedwith metformin (500mg Bid) or megestrol (40mg daily), respectively, for three months. After this period thepatients were evaluated by another endometrial biopsy to assess the impact of the two drugs in restoring normalendometrial histology.
Results: Our findings revealed that metformin could induce endometrial atrophy in 21out of 22 patients (95.5%) while this positive response was achieved in only 13 out of 21 patients (61.9%) in themegstrol group. In addition two low grade endometrial carcinomas in the metformin group responded verywell.
Conclusions: We conclude that metformin could be used as an effective antiestrogenic agent in control ofabnormal endometrial proliferative disorders.