[Fertility-preserving treatment outcomes in endometrial cancer and atypical hyperplasia patients with different molecular profiles].

To investigate the impact of molecular classification and key oncogenes on the oncologic outcomes in patients with endometrial carcinoma (EC) and atypical endometrial hyperplasia (AEH) receiving fertility-preserving treatment. Patients with EC and AEH undergoing progestin-based fertility-preserving treatment and receiving molecular classification as well as key oncogenes test at Obstetrics and Gynecology Hospital, Fudan University from January 2021 to March 2023 were reviewed. Hysteroscopic lesion resection and endometrial biopsy were performed before initiating hormone therapy and every 3 months during the treatment to evaluate the efficacy. The risk factors which had impact on the treatment outcomes in EC and AEH patients were further analyzed. Of the 171 patients analyzed, the median age was 32 years, including 86 patients with EC and 85 patients with AEH. The distribution of molecular classification was as follows: 157 cases (91.8%) were classified as having no specific molecular profile (NSMP); 9 cases (5.3%), mismatch repair deficient (MMR-d); 3 cases (1.8%), POLE-mutated; 2 cases (1.2%), p53 abnormal. No difference was found in the cumulative 40-week complete response (CR) rate between the patients having NSMP or MMR-d (61.6% vs 60.0%; =0.593), while the patients having MMR-d had increased risk than those having NSMP to have recurrence after CR (50.0% vs 14.4%; =0.005). Multi-variant analysis showed PTEN gene multi-loci mutation (=0.413, 95%: 0.259-0.658; <0.001) and PIK3CA gene mutation (=0.499, 95%: 0.310-0.804; =0.004) were associated with a lower cumulative 40-week CR rate, and progestin-insensitivity (=3.825, 95%: 1.570-9.317; =0.003) and MMR-d (=9.014, 95%: 1.734-46.873; =0.009) were independent risk factors of recurrence in EC and AEH patients. No difference in cumulative 40-week CR rate is found in the patients having NSMP or MMR-d who received progestin-based fertility-preserving treatment, where the use of hysteroscopy during the treatment might be the reason, while those having MMR-d have a higher risk of recurrence after CR. Oncogene mutation of PTEN or PIK3CA gene might be associated with a lower response to progestin treatment. The molecular profiles help predict the fertility-preserving treatment outcomes in EC and AEH patients.