This study aimed to evaluate the efficacy of the 2020 European Society of Gynecological Oncology/European Society for Radiotherapy and Oncology/European Society of Pathology (ESGO/ESTRO/ESP) guidelines for endometrial cancer (EC). Additionally, a novel risk category incorporating clinicopathological and molecular factors was introduced. The predictive value of this new category for recurrence and survival in Korean patients with EC was assessed, and comparisons were made with the 2013 and 2016 European Society of Medical Oncology (ESMO) risk classifications. Patients with EC were categorized into the POLE-mutated (POLEmut), mismatch repair-deficient (MMRd), p53-aberrant (P53abn), and nonspecific molecular profile (NSMP) subtypes. Recurrence, survival, and adjuvant therapy were assessed according to each classification. Notably, patients with the POLEmut subtype showed no relapse, while patients with the P53abn subtype exhibited higher recurrence (31.8%) and mortality rates (31.8%). Regarding adjuvant therapy, 33.3% of low-risk patients were overtreated according to the 2020 ESGO/ESTRO/ESP guidelines. Overall and progression-free survival differed significantly across molecular classifications, with the POLEmut subtype showing the best and the P53abn subtype showing the worst outcomes. The 2020 ESGO molecular classification system demonstrated practical utility and significantly influenced survival outcomes. Immunohistochemistry for TP53 and MMR, along with POLE sequencing, facilitated substantial patient reclassification, underscoring the clinical relevance of molecular risk categories in EC management.
Keywords: endometrial cancer; mismatch repair; molecular classification; p53; polymerase epsilon.