The Effect of Medroxyprogesterone Acetate on Angiogenesis in Complex Endometrial Hyperplasia

Objective: To evaluate the effect of orally administered medroxyprogesterone acetate upon angiogenesis in the myometrium of patients with complex endometrial hyperplasia.

Methods: Microvessel counts in the myometrium of consecutive patients with complex endometrial hyperplasia, treated with oral medroxyprogesterone acetate prior to hysterectomy (n = 12), were compared with microvessel counts of consecutive control patients with complex endometrial hyperplasia without prehysterectomy medroxyprogesterone acetate treatment (n = 15). All specimens were stained immunohistochemically for factor VIII-related antigen as a sensitive and specific marker for vascular endothelium. Areas with the highest angiogenic intensity, within the myometrium immediately underlying complex endometrial hyperplasia, were selected. Three fields (x400) were selected for each slide, and the mean microvessel count per high-power field was calculated. Statistical analysis included factorial analysis of variance/covariance, and multiple regression analysis with P < 0.05 considered significant throughout.

Results: Microvessel counts of uterine specimens of patients with complex endometrial hyperplasia treated with oral medroxyprogesterone acetate were significantly lower than microvessel counts of control patients with complex endometrial hyperplasia without medroxyprogesterone acetate therapy (median 20, range 11-37 versus median 38, range 20-130, respectively, P < 0.001).

Conclusion: Orally administered medroxyprogesterone acetate has a significant antiangiogenic effect upon myometrium immediately underlying complex endometrial hyperplasia.