Prognostic performance of the 2023 FIGO staging schema for endometrial cancer

Objective: To assess the prognostic performance of the 2023 International Federation of Gynecology and Obstetrics (FIGO) endometrial cancer staging schema.

Methods: This retrospective cohort study queried the Commission-on-Cancer's National Cancer Database. Study population was 129,146 patients with stage I-IV endometrial cancer per the 2009 FIGO staging schema. Stage-shifting and overall survival (OS) were assessed according to the 2023 FIGO staging schema.

Results: Upstage (IA → II, 21.4 %; IB → II, 53.0 %) and downstage (IIIA→IA3, 22.2 %) occurred in both early and advanced diseases. Inter-stage prognostic performance improved in the 2023 schema with widened 5-year OS rate difference between the earliest and highest stages (68.2 % to 76.9 %). Stage IA1-IIB and IIC had distinct 5-year OS rate differences (85.8-96.1 % vs 75.4 %). The 5-year OS rate of the 2009 stage IIIA disease was 63.9 %; this was greater segregated in the 2023 schema: 88.0 %, 62.4 %, and 55.7 % for IIIA→IA3, IIIA1, and IIIA2, respectively (inter-substage rate-difference, 32.3 %). This 5-year OS rate of stage IA3 disease was comparable to the 2023 stage IB-IIB diseases (88.0 % vs 85.8-89.5 %). In the 2023 stage IIIC schema (micrometastasis rates: 29.6 % in IIIC1 and 15.6 % in IIIC2), micrometastasis and macrometastasis had the distinct 3-year OS rates in both pelvic (IIIC1-i vs IIIC1-ii, 84.9 % vs 71.1 %; rate-difference 13.8 %) and para-aortic (IIIC2-i vs IIIC2-ii, 82.9 % vs 65.2 %; rate-difference 17.7 %) nodal metastasis cases. The 5-year OS rate of the 2009 stage IVB disease was 23.4 %; this was segregated to 25.4 % for stage IVB and 19.2 % for stage IVC in the 2023 staging schema (rate-difference, 6.2 %).

Conclusion: The 2023 FIGO endometrial cancer staging schema is a major revision from the 2009 FIGO schema. Almost doubled enriched sub-stages based on detailed anatomical metastatic site and incorporation of histological information enable more robust prognostication.