Introduction A joint ESGO/ESTRO/ESP committee updated their evidence-based endometrial cancer guidelines in 2020 and suggested a new risk category including both clinicopathologic and molecular factors. We applied the new risk grouping and compared the ESMO 2013 and ESMO 2016 risk classification system.

Methods The histological subtype, myometrial invasion, grade, and presence of lympho-vascular space invasion were confirmed. Prior to POLE sequencing, immunohistochemistry was used to analyze the MLH1, MSH2, MSH6, PMS2 and p53. We investigated prognosis and the adjuvant therapy according to the different classifications of the 2013 ESMO, 2016 ESMO, and 2020 ESGO.

Results A total of 137 endometrial cancer patients were identified. Molecular subtyping showed 6.6% POLEmut, 18.2% MMRd, 16.8% p53abd, and 58.4% NSMP, with a statistically significant difference in overall survival (p < 0.001). According to molecular classification, the survival rate for p53abd was the lowest at 34.8%, but all 9 patients with POLEmut survived. Ten patients were reclassified downward, and five patients were reclassified upward. According to the 2020 ESGO classification, the high risk group received no adjuvant therapy in 22.8% and only brachytherapy in 3.2% whereas 16.7% of the low risk group underwent EBRT.

Conclusion/Implications In comparison to the 2016 ESMO classification, 15 of the 137 (10.9%) patients were reclassified by the 2020 ESGO new molecular classification. The use of molecular risk categories in 2020 is practical and exhibits a considerable difference in survival. IHC for TP53 and MMR and POLE sequencing can result in a considerable proportion of patients having their risk groups upgraded or downgraded.