Grade 1 Endometrioid Carcinoma With an Area of Serous Carcinoma Less than 5% Is More Aggressive than Stage IA Pure-type Grade 1 Endometrioid Carcinoma

Abstract

Background/aim: In 2020, the percentages were removed from the World Health Organization's criteria for mixed carcinoma. The aim was to examine the clinical significance of an area of serous carcinoma (SC) <5%.

Patients and methods: Our study included 236 patients with the 2009 International Federation of Obstetrics and Gynecology (FIGO) stage IA grade 1 endometrioid carcinoma (EG1) from multiple hospitals. EG1 patients with an area of SC <5% and those with pure-type EG1 were retrospectively compared.

Results: In the multivariate analysis for recurrence, an area of SC <5% was an independent risk factor [hazard ratio (HR)=101.51, p<0.01]. In the multivariate analysis for progression-free survival, an area of SC <5% was identified as a negative prognostic factor (HR=62.43, p<0.01).

Conclusion: EG1 with an area of SC <5% may be more aggressive than pure-type EG1 at FIGO stage IA.

Keywords: Endometrial carcinoma; World Health Organization criteria; endometrioid carcinoma; mixed carcinoma; serous carcinoma.