Stage IA3 endometrial cancer in the FIGO 2023 classification: a case of clarity or complexity?

Synchronous endometrial and ovarian endometrioid carcinomas, found in up to 10% of ovarian and 5% of endometrial cancers, remain without clear diagnostic criteria or standardized treatment approaches. The 2023 International Federation of Gynaecology and Obstetrics (FIGO) classification clarified staging, categorizing confined disease as stage IA3 or IIIA1, significantly impacting treatment decisions. In our study of 25 patients with concurrent endometrial and ovarian tumors, centralized pathology review and treatment were conducted to compare the 2009 versus the 2023 FIGO classifications. We found that applying the 2023 classification and European Society of Gynaecological Oncology risk stratification led to stage shifts in 5 patients (20%): 2 were downstaged (no adjuvant therapy needed), and 3 were upstaged (high risk). Among the 11 patients whose disease was limited to the uterus and ovaries, 5 met the criteria for stage IA3 and none experienced recurrence, including 2 patients managed with surgery alone. The FIGO 2023 stage IA3 classification enables more precise risk stratification, particularly, in cases with low-grade tumors, estrogen receptor positivity, and favorable molecular profiles (POLE-mutated or p53 wild-type and non-specific molecular profile). However, it raises 2 critical issues: the need for appropriate staging surgery and the debate regarding the optimal grading system for ovarian endometrioid carcinoma.