Clinical and pathological responses of progestin therapy for non-atypical endometrial hyperplasia: A prospective study

Aims: To evaluate the clinical and pathological responses and factors predicting non-responders to various progestins currently prescribed for the treatment of non-atypical endometrial hyperplasia. Methods: A prospective observational study was conducted in the Gynecologic Endocrinology Unit, Faculty of Medicine, Siriraj Hospital, Thailand, from 1998 to 2003. A 6-month course of progestin therapy was offered to all patients. The clinical response was evaluated from the vaginal bleeding pattern during the first 4 months of treatment. The pathological response was evaluated from the histopathology of the endometrium after completion of the 6-month therapy. Results: Of 250 registered patients, the number of cases qualified for the evaluation of the clinical and pathological response were 198 and 134 cases, respectively, revealing the overall clinical and pathological response rates of 93.4% and 92.5%, respectively. Among 13 clinical non-responders, 84.6% might have associated pelvic pathology. Among 10 pathological non-responders, three had surgical treatment, and progressive disease was found in one case. Significant factors predicting clinical non-responders included a history of prior bleeding (odds ratio [OR] = 8.79, 95% confidence interval [CI] = 1.63, 47.53), the presence of associated pelvic pathology (OR = 25.52, 95% CI = 3.21, 203.01), and treatment using progestins other than medroxyprogesterone acetate. Factors predicting pathological non-responders were not statistically significant. Conclusions: The current regimens of progestin therapy for non-atypical endometrial hyperplasia have high response rates. Patients who fail to have a clinical response should be evaluated for associated pelvic pathology. Follow-up endometrial biopsy should be offered to the patients, because 7.5% have persistent or progressive lesions, necessitating aggressive treatment.