Non-endometrioid endometrial cancer: analysis of recurrence pattern and identification of prognostic and treatment factors affecting recurrence and survival

PurposeWe investigated the characteristics of recurrence pattern and survival of patients with non-endometrioid endometrial cancer (NEEC) and attempted to identify prognostic and treatment factors affecting disease-free survival (DFS) and overall survival (OS) of these patients.MethodsFifty-seven patients with histologically confirmed International Federation of Gynecology and Obstetrics (FIGO) stage IA-IVA NEEC from February 2003 to December 2021 were retrospectively analyzed.ResultsThe 5-year DFS and OS rates of the total cohort were 50.6% and 56.1%, respectively. Recurrence occurred in 28 patients (49.1%) during follow-up, and the most common recurrence pattern was distant metastasis (DM; 78.6% of total recurrences). The occurrence of relapse significantly reduced 5-year OS (recurrence group vs. non-recurrence group: 12.5% vs. 100%; p < 0.001). In univariate analysis, adjuvant radiotherapy (RT) group showed significantly higher 5-year DFS (56.7% vs. 37.9%; p = 0.04), local recurrence-free survival (91.6% vs. 50.5%; p = 0.01), and regional recurrence-free survival (88.2% vs. 56.5%; p < 0.01) than the non-RT group. In multivariate analysis, advanced FIGO stage was identified as a negative prognostic factor for DFS and OS. Lymphovascular space invasion (LVSI) and adjuvant RT were independent prognostic factors for DFS.ConclusionThe most common recurrence pattern observed in patients with NEEC was DM. FIGO stage and LVSI were identified as prognostic factors for survival, and RT was identified as a therapeutic modality that could increase DFS. To improve the OS of patients with NEEC, the addition of effective chemotherapy that can reduce DM may be important.