To investigate oncological and reproductive outcomes in patients with mismatch repair-deficient (MMRd) endometrial endometrioid carcinoma (EEC) or atypical endometrial hyperplasia (AEH) undergoing fertility-preserving treatment to inform clinical management of this molecular subtype. Clinical and pathological data from 14 patients with MMRd EEC or AEH who received fertility-preserving treatment at Peking Union Medical College Hospital from January 2020 to December 2023 were retrospectively analyzed. The mean age at diagnosis of the patients was 33.6 ± 4.2 years. Loss of MLH1/PMS2 expression was the most common immunohistochemical abnormality, followed by loss of MSH6, MSH2/MSH6, and PMS2 expression. Among the 12 patients who underwent germline genetic testing, pathogenic/likely pathogenic germline variants in MMR genes were identified in three patients. During the follow-up period (median 34.5 months, range 26–117 months), seven patients achieved complete remission (CR), with a median time to CR of 8 months. The recurrence rate among these patients was 57.1%, and the median time to recurrence was 11 months. Nine patients underwent surgery after treatment failure or recurrence, with postoperative pathology revealing histologic upgrading and/or metastasis in eight patients. Two patients successfully conceived through assisted reproductive technology and achieved live births. Patients with MMRd EEC or AEH undergoing fertility-preserving treatment demonstrated relatively low remission rates, high recurrence rates, and suboptimal reproductive outcomes. Careful risk assessment and close surveillance for recurrence are warranted for patients desiring fertility.
Zhang et al. (Wed,) studied this question.