Aromatase inhibitor “letrozole” versus progestin “norethisterone” in women with simple endometrial hyperplasia without atypia: A prospective cohort trial

ObjectiveTo evaluate the effectiveness of the aromataze inhibitor “letrozole” to progestin “norethisterone” for women with simple endometrial hyperplasia without atypia.Subjects and methodsOne hundred women with a histo-pathological diagnosis of simple endometrial hyperplasia without atypia were divided into two groups: Groups A and B. Group A included 50 patients who received a daily 5 mg dose of letrozole for three successive months. Group B included the other 50 patients who received norethisterone 10 mg daily by non-stop regimen for 3 months. All patients in both groups were reevaluated after treatment. Women diagnosed with progressive or persistent endometrial hyperplasia at the second curettage were asked to continue on the same medication for another 3 months. Transvaginal sonography as well as serum estradiol level measurement were performed before the start of treatment and 3 months after treatment.ResultsDespite that there was no statistically significant difference between the two groups as regards the proportion of women whose endometrial sample revealed resolution, regressing or persistence after 3 months of treatment. However, endometrial thickness was significantly thinner in women who received letrazole than in women who received norethisterone (mean difference 0.12 mm, 95% CI: 0.22–0.01, P = 0.02). Serum E2 level was significantly lower in the Group A compared to Group B (mean difference 9.1 pg, 95% CI: 13.74–4.45, P < 0.001).ConclusionLetrozole is as effective as norethisterone for women with abnormal uterine bleeding due to endometrial hyperplasia without atypia.