Molecular Classification Guides Fertility-Sparing Treatment for Endometrial Cancer and Atypical Hyperplasia Patients

The objective of this study was to investigate the significance of molecular classification in guiding treatment decisions for patients with endometrial cancer (EC) or atypical hyperplasia (AH) undergoing fertility-sparing treatment (FST), particularly for those with non-NSMP subtypes.

We conducted a retrospective cohort study involving EC/AH patients undergoing FST and molecular classification using next-generation sequencing at Peking University People's Hospital between June 2020 and September 2023.

A total of 118 EC/AH patients were included, including 92 cases with NSMP, 11 with MMRd, 11 with POLEmut, and 4 with p53abn. (1) Of the 11 patients with MMRd, 6 achieved a complete response (CR) with 1 case receiving progestin, 3 cases showed insensitivity to the initial progestin before transitioning to a combined regimen of progestin and a PD-1 inhibitor, and 2 cases initially received progestin plus a PD-1 inhibitor. There were no significant differences in the cumulative CR rates between the MMRd and NSMP subgroups but a trend of a lower relapse-free-survival (RFS) rate for the MMRd subgroup (p = 0.074). (2) Of the 11 cases with POLEmut, 10 achieved CR but 4 relapsed. There was also a trend for a lower RFS rate in the POLEmut patients (p = 0.069) compared with the NSMP subgroup. (3) Three of the four patients with p53mut achieved CR after treatment with the GnRHa plus LNG-IUS regimen.

The selection of appropriate regimens may improve FST outcomes in EC/AH patients with molecular classification of non-NSMP subtypes. Immunotherapy is an effective fertility-preserving approach for patients with MMRd.