Effect of Letrozole on Endometrial Histology in Patients with Disordered Proliferative Endometrium and Simple Hyperplasia

This is a preliminary study investigating the efficacy of aromatase inhibitor letrozol on endometrial histology in patients with disordered proliferative endometrium or simple hyperplasia. In a randomized clinical trial, 92 patients with abnormal uterine bleeding who had disordered proliferative endometrium or simple hyperplasia in endometrial biopsy, were randomized into case and control groups. patients received 2.5 mg of letrozole daily in case group (n=46) and 40 mg of megestrol acetate daily in control group (n=46) for 3 months. Endometrial biopsy was performed 3 to 4 weeks after completion of therapy to assess response. After intervention in letrozole group, response to treatment was seen in 93% cases (including endometrial atrophy in 58.7% cases and weakly proliferative endometrium in 34.78% cases) and in megestrol group response to treatment was seen in 85% cases (including endometrial atrophy in 41.3% cases and weakly proliferative endometrium in 43.47% cases). The difference between two groups was not statistically significant (P=0.31). The results of this study show that pre and post menopausal women with disordered proliferative endometrium or simple hyperplasia can be successfully treated with letrozole alone. However, due to the lack of significant difference between the two groups, further studies with larger sample size is recommended for better clearance of the topic.