Trends and characteristics of fertility-sparing treatment for atypical endometrial hyperplasia and endometrial cancer in Japan: a survey by the Gynecologic Oncology Committee of the Japan Society of Obstetrics and Gynecology

Objective: The objective of this study was to examine the current trends in fertility-sparing (FS) treatment for young atypical endometrial hyperplasia (AEH) and endometrial cancer (EC) patients in Japan. Methods: This study was conducted by the Committee on Gynecologic Oncology of the Japan Society of Obstetrics and Gynecology (JSOG) in the 2017-2018 fiscal year. A nationwide, retrospective questionnaire-style survey-as performed. We collected the data of 413 patients from 102 JSOG gynecological cancer registered institutions. Results: FS treatment was performed with medroxyprogesterone (MPA) (87.2%) or MPA + metformin (11.6%). Pathological complete remission (CR) after initial treatment was achieved in 78.2% of patients. The significant clinicopathological factors correlated to CR after initial treatment were histology (AEH vs. endometrioid carcinoma grade 1 [ECG1]), body mass index (BMI) (<25 vs. >= 25 kg/m2), and treatment period (<6 vs. >= 6 months). ECG1, time to complete remission (TTCR) >= 6 months, maintenance therapy (-), and pregnancy (-) were associated with a significantly higher risk of recurrence on multivariate analysis. The total pregnancy rate was 47%, and the live birth rate was 40.1%. Patients who received infertility treatments showed a higher live birth rate (50.6%) than those who did not (7.7%). Conclusion: In this survey, we confirmed that FS treatment in Japan is centered on MPA alone and in combination with metformin, and that the treatment efficacy is similar to that reported in previous reports. A multicenter survey study in Japan showed FS treatment for young AEH and EC patients in compliance with the indications is feasible.