Fertility-sparing treatment by high dose oral medroxyprogesterone acetate for endometrial cancer and atypical hyperplasia in young women: A multicentric phase II study

Abstract

5022 Background: Standard treatment for endometrioid adenocarcinoma, stage Ia (EC) and atypical endometrial hyperplasia (AH) is hysterectomy even in young women. High-dose of Medroxyprogesterone Acetate (MPA) is one of the options for patients who desire preserving childbearing potential. Nevertheless, the optimal dose or duration and curative rate of MPA therapy for in EC and AH in young women are still uncertain. Methods: Multicentric prospective study was carried out by 16 institutions in Japan. Twenty-five EC patients with no myometrial or cervical invasion and 17 AH patients under 40 years of age were enrolled. All patients were given MPA 600mg with low dose aspirin orally daily, and the treatment were continued for 26weeks as far as the lesions responded to it. Endometrial tissue was collected and histologically assessed at 8, 16, 26 weeks of the treatment. The diagnoses were confirmed by central pathological review board. Estrogen-progesterone therapy or assisted reproductive technologies were provided for the responders after MPA therapy. Complete response (CR) rate was the primary endpoint and toxicity, rate of pregnancy and progression free interval (PFI) were the secondary endpoints. Results: CR was found in 44% in EC and 82% in AH. Overall CR rate was 60%. Any grade 3 toxicities except body weight increase in two patients or therapeutic death were not observed. So far 9 pregnancies and 4 normal deliveries have been recorded after MPA therapy. Twelve recurrences were found in 30 CR patients (40%) between 7 to 22 months, they rechallenged MPA or underwent hysterectomy. No patients died of disease. PFI of EC and AH were 20.1months and 28.5 months respectively. Conclusions: The efficacy of fertility-sparing treatment by MPA for EC and AH was proved by this first prospective trial. Even in the CR patients, close follow-up is required because of their high recurrence rate. No significant financial relationships to disclose.