Objective Our aim was to evaluate the prognostic significance of the revised 2009 International Federation of Gynecology and Obstetrics (FIGO) staging criteria in patients with uterine serous carcinoma (USC).

Materials and Methods We retrieved clinical and histopathologic data on women with USC from 2 large academic centers. Age, race, stage, myometrial invasion, angiolymphatic invasion, and adjuvant therapy were analyzed using Kaplan-Meier and Cox regression models.

Results A total of 168 patients were included. Three-year survival rate was 81% for revised stage I, 52% for stage II, 46% for stage III, and 19% for stage IV. Survival was not significantly different when comparing overall 1988 FIGO stage I or II to 2009 FIGO stage I or II. The 3-year survival rate for 1988 stage IA (93%), IB (75%), and IC (60%) significantly differed (P = 0.02). When patients were restaged using the 2009 staging system, the 3-year overall survival of 2009 stage IA dropped to 83.4% and 68.8% for stage IB. New FIGO stage, myometrial invasion, angiolymphatic invasion, and administration of chemotherapy all remained independent predictors of survival on multivariate analysis (P < 0.05). Of note, extrauterine disease was observed in 22% of patients without myometrial invasion. Age and race were not prognostic factors for either classification.

Conclusions The streamlined 2009 FIGO criteria do not adequately delineate survival for USC in early-stage disease. The 1988 FIGO classification correctly identified 3 subgroups of stage I USC patients with significantly different survival that is lost with the elimination of the most favorable 1988 stage IA subgroup. Because evaluation for adjuvant therapy and patient planning may change based on survival information, further evaluation of more appropriate USC staging is warranted. Caution should be taken when evaluating therapeutic response and comparing studies using these revised criteria in the future.