Introduction/Background Atypical endometrial hyperplasia (AEH) is an obligate precancer of the endometrium, which in terms of standard treatment, like the treatment of endometrial cancer (EC), involves the removal of the uterus. By the time of the primary diagnosis of AEH and EC, 5–7% of women are below 45 years at diagnosis have not completed childbearing. In these cases, the use of alternative therapies to preserve fertility and the possibility of delayed motherhood is very relevant. The aim of this study was to evaluate oncologic and reproductive outcomes in young women with AEH/EC, who underwent fertility-sparing treatment.

Methodology The study included data from 64 patients (AEH – 48, EC – 18) who were treated at NN Alexandrov National Cancer Centre (November 2017 – April 2022). The median age was 33 (range 20–42) years. After performing hysteroresectoscopy the following hormone therapy schemes were used: 1) levonorgestrel releasing intrauterine device (LNG-IUD), 2) medroxyprogesterone (500 mg/d orally), 3) LNG-IUD + GnRH analogues (3.75 mg orally once per 28-day, no.3). The duration of treatment was 3–6 months.

Results Median follow-up time was 17.7 (range 1–55) months. A complete response (presence of endometrial atrophy in the morphology report) was noted in 47/48 (98.0%) and 14/18 (78.0%) patients, respectively. After hormonal therapy of AEH, spontaneous pregnancy occurred in 10 (21.3%) women: in two of them it ended in term delivery, in 8 – in spontaneous miscarriages. After hormone therapy of an EC, pregnancy occurred in 4 (28.6%) patients, in 2 cases the pregnancy ended in term delivery.

Conclusion In our study, the fertility-sparing approach demonstrated a safe and effective outcomes in young women with AEH/EC (complete response rates – in 98.0% and 78.0% patients, respectively; fertility rates – 21.3% and 28.6%, respectively) because patient selection, treatment, and follow-up were centralized and limited to a single Cancer Center.