Association of Molecular Classification with FIGO Stage and Survival Outcomes in Endometrial Cancer

Background and Objectives: Molecular classification has emerged as a key determinant of prognosis in endometrial cancer and has recently been incorporated into the 2023 FIGO staging system. Tumors are categorized into four molecular subgroups-POLE-mutated (POLEmut), p53-abnormal (p53abn), mismatch repair-deficient (dMMR), and no specific molecular profile (NSMP)-each associated with distinct biological behavior and clinical outcomes. However, real-world data evaluating the relationship between molecular classification, FIGO stage distribution, and survival outcomes remain limited. Materials and Methods: This retrospective study included patients diagnosed with endometrial cancer between 2014 and 2022 at Dokuz Eylül University Hospital. Tumor samples were classified according to the ProMisE molecular algorithm using next-generation sequencing for POLE mutations and immunohistochemical evaluation of mismatch repair proteins and p53 expression. Clinicopathological characteristics, recurrence patterns, and survival outcomes were analyzed. Appropriate statistical analyses were performed. Results: A total of 156 patients were included (mean age 60.2 ± 10.0 years). The most common histology was endometrioid carcinoma (51.9%). Molecular subgroup distribution was NSMP (58.3%), dMMR (25%), p53abn (11.5%), and POLEmut (5.1%). Most patients presented with early-stage disease (83.4%). According to the 2023 FIGO molecular staging, 8.3% were classified as stage 2C m-p53abn and 5.8% as Stage 1Am-POLEmut. After a median follow-up of 39.5 months, the overall survival rate was 81.6%. Survival differed significantly across molecular subgroups, with the most favorable outcomes observed in the POLEmut (100%), followed by NSMP (85.2%), dMMR (78.4%), and p53abn (64.7%) (p = 0.011). Lymph node metastasis was significantly more frequent in the p53abn subgroup (p = 0.002), whereas distant metastasis rates did not differ between groups. Conclusions: Molecular classification was associated with differences in FIGO stage distribution and survival outcomes in this retrospective cohort and may provide additional prognostic information beyond traditional clinicopathological factors. The integration of molecular profiling into routine practice and staging systems may enable improved risk assessment and facilitate more personalized therapeutic strategies in endometrial cancer.