Analysis of Prognostic Factors and Cancer-Specific Survival in Patients with Undifferentiated and Dedifferentiated Endometrial Carcinoma Undergoing Various Postoperative Adjuvant Therapies

Purpose: To investigate prognostic factors affecting cancer-specific survival (CSS) and to analyze the survival outcomes of patients with undifferentiated and dedifferentiated endometrial carcinoma (UDEC) who underwent various postoperative adjuvant therapies.
Methods: The independent risk factors affecting CSS were studied using univariate and multivariate Cox regression analysis, and CSS in the presence of various postoperative treatments was evaluated using Kaplan-Meier method based on the cohort with pathologically confirmed UDEC from the Surveillance, Epidemiology, and End Results (SEER) database. Meanwhile, the study included 18 cases with UDEC in our center and explored their molecular characteristics and prognosis.
Results: Between 2000 and 2019, a total of 443 patients were included from the SEER database. The median CSS duration was 14 months, with corresponding 3- and 5-year CSS rates of 45.9% and 44.0%, respectively. Factors such as pTNM stage, surgical resection of primary lesion, and chemoradiation independently influenced CSS. Postoperative chemotherapy alone improved CSS in patients with initial tumor spread beyond the uterus (pT3 and pT4), or lymph node (LN) invasion, or distant metastases. Additionally, postoperative radiotherapy enhanced CSS in patients who had undergone postoperative chemotherapy, those with primary tumors progressing to stage pT3, and those with LN involvement but without distant metastases. Of the 18 patients diagnosed at our center, with a median follow-up of 15.5 months, one experienced relapse and two succumbed to UDEC, who exhibited aberrant p53 expression in immunohistochemical staining.
Conclusion: Postoperative chemotherapy and radiotherapy are beneficial for UDEC patients with tumors extending beyond the uterus or involving lymph nodes.

Keywords: undifferentiated and dedifferentiated endometrial carcinoma, cancer-specific survival, prognostic factors, postoperative adjuvant therapy