Comparative Performance of the 2009 International Federation of Gynecology and Obstetricsʼ Staging System for Uterine Corpus Cancer

OBJECTIVE:To perform a population-based analysis comparing the performance of the 1988 and 2009 International Federation of Gynecology and Obstetrics (FIGO) staging systems. METHODS:Women with endometrioid adenocarcinoma of the uterus treated between 1988 and 2006 and recorded in the Surveillance, Epidemiology, and End Results database were analyzed. Women were classified based on 1988 and 2009 FIGO staging systems. Major changes in the 2009 system include1) classification of patients with stage IA and IB tumors as stage IA; 2) elimination of stage IIA; and 3) stratification of stage IIIC into pelvic nodes only (IIIC1) or paraaortic nodal (IIIC2) involvement. Survival and use of adjuvant therapy were analyzed. RESULTS:A total of 81,902 women were identified. Based on the 1988 staging system, survival for stage IA was 90.7% (95% confidence interval [CI], 90–91%) compared with 88.9% (95% CI 88–89%) for IB tumors. In the 2009 system, survival was 89.6% (95% CI 89–90%) for stage IA and 77.6% (95% CI 76–79%) for stage IB. The survival for FIGO 1988 stage IIA was superior to stage IC, whereas in the 2009 system, survival for stage II was inferior to all stage I patients. The newly defined stage IIIC substages are prognostically different. Survival for stage IIIC1 was 57.0% (95% CI 54–60%) compared with 49.4% (95% CI 46–53%) for stage IIIC2. CONCLUSION:The 2009 FIGO staging system for uterine corpus cancer is highly prognostic. The reduction in stage I substages and the separation of stage III will further clarify important prognostic features. LEVEL OF EVIDENCE:III