Multicenter phase II study of fertility-sparing treatment with medroxyprogesterone acetate for endometrial carcinoma and atypical hyperplasia in young women

Purpose: To assess the efficacy of fertility-sparing treatment using medroxyprogesterone acetate (MPA) for endometrial carcinoma (EC) and atypical endometrial hyperplasia (AH) in young women. Patients and Methods: This multicenter prospective study was carried out at 16 institutions in Japan. Twenty-eight patients having EC at presumed stage IA and 17 patients with AH at younger than 40 years of age were enrolled. All patients were given a daily oral dose of 600 mg of MPA with low-dose aspirin. This treatment continued for 26 weeks, as long as the patients responded. Histologic change of endometrial tissue was assessed at 8 and 16 weeks of treatment. Either estrogen-progestin therapy or fertility treatment was provided for the responders after MPA therapy. The primary end point was a pathologic complete response (CR) rate. Toxicity, pregnancy rate, and progression-free interval were secondary end points. Results: CR was found in 55% of EC cases and 82% of AH cases. The overall CR rate was 67%. Neither therapeutic death nor irreversible toxicities were observed; however, two patients had grade 3 body weight gain, and one patient had grade 3 liver dysfunction. During the 3-year follow-up period, 12 pregnancies and seven normal deliveries were achieved after MPA therapy. Fourteen recurrences were found in 30 patients (47%) between 7 and 36 months. Conclusion: The efficacy of fertility-sparing treatment with a high-dose of MPA for EC and AH was proven by this prospective trial. Even in responders, however, close follow-up is required because of the substantial rate of recurrence.