Prognostic factors of oncologic outcomes after fertility-preservative management with progestin in early-stage of endometrial cancer

Background: The aim of this study was to evaluate efficacy of various fertility-preservative treatments with progestin and analyze prognostic factors in Stage 1A of endometrial cancer. Materials and Methods: This retrospective study involved four Korean university hospitals. Data were collected from 43 women who were under the age of 40 with presumed stage IA endometrial cancer determined by magnetic resonance imaging and treated from January 2014 to December 2017. All of the patients were administered hormonal therapy for fertility preservation. Twenty-five patients received oral progestin with a levonorgestrel-releasing intrauterine system (LNG-IUS) for 6–24 months, and 18 patients received high-dose oral progestin for the same period of time. Oncologic outcomes were evaluated. Prognostic factors for pathologic response to progestin were identified by logistic regression analysis. Results: Complete response (CR) was achieved by 72.1% of patients (31/43), and the average time to CR was 4.2 (Stable disease [SD] 3.4) months (range, 3–9 months). Partial response was achieved by 7.0% of patients (3/43), SD by 9.3% (4/43), and progressive disease by 11.6% (5/43). Of the CR patients, 41.9% (13/31) achieved pregnancy with the median follow-up period of 12.5 (SD 7.6) months (range: 3–50 months). No irreversible toxicity or therapy-associated death occurred. Multivariate analysis showed that high endometrial thickness ratio of pre- and posttreatment measured at 2 months from the treatment initiation (≥0.55, Odds ratio [OR]: 19.018; 95% confidence intervals (CI): 1.854–195.078; P = 0.013) and oral progestin without LNG-IUS (OR: 13.483; 95% CI: 1.356–134.069; P = 0.026) might be related with unfavorable prognostic factors for CR. Conclusion: This study shows that progestin-based fertility-preservative treatment might be a feasible option for stage 1A endometrial cancer. It also identifies that low endometrial thickness ratio and oral progestin with LNG-IUS combination therapy might be related with favorable response to hormonal treatment.