Uterine Effects of 3-Year Raloxifene Therapy in Postmenopausal Women Younger Than Age 60

Abstract

In Brief Objective To assess the uterine effects of 3 years of therapy with raloxifene in healthy, postmenopausal women under age 60. Methods Integrated data from two identically designed, randomized, double-masked, placebo-controlled clinical trials were analyzed. Nine hundred sixty-nine healthy women with uteri (ages 45 through 60, 2 to 8 years postmenopausal) were assigned randomly to raloxifene 30, 60, or 150 mg per day, or an identical placebo for 3 years. Endometrial thickness was evaluated with transvaginal ultrasonography every 6 months for 2 years and again after 3 years. Further uterine evaluation, including endometrial sampling if necessary, was initiated for vaginal bleeding or findings of endometrial thickness greater than 5 mm. Results Endometrial thickness was unchanged by raloxifene and not significantly different from placebo at any time. One hundred seventy-two women had at least one episode of endometrial thickness greater than 5 mm or vaginal bleeding distributed equally among all groups. A total of 102 (10.5%) women underwent endometrial sampling at least once: 15 (1.5%) for vaginal bleeding, 78 (8.0%) for endometrial thickness greater than 5 mm, and nine (0.9%) for other reasons. There were no significant treatment differences in the proportion of women sampled, in the clinical findings, or in the histologic diagnoses. Conclusion Raloxifene given to healthy postmenopausal women at doses from 30 to 150 mg per day does not stimulate uterine growth and does not cause vaginal bleeding, spotting, or discharge through 3 years of therapy. Thus, any bleeding during therapy should be deemed unexpected and prompt a clinical evaluation. Raloxifene therapy for up to 3 years did not cause endometrial thickening or proliferation and was not associated with signs or symptoms suggestive of uterine pathology in healthy postmenopausal women.