Validation of the 2018 FIGO cervical cancer staging system

Abstract

Objective: To validate the revised 2018 International Federation of Gynecology and Obstetrics (FIGO) staging system for cervical cancer, with a particular focus on stage IB and stage III disease.

Methods: Two retrospective cohort studies were conducted using The Surveillance, Epidemiology, and End Results Program between 1988 and 2014. The stage IB cohort consisted of node-negative FIGO stage IB1 (tumor size <2 cm), IB2 (2-3.9 cm), and IB3 (≥4 cm) cervical cancer. The stage III cohort consisted of FIGO stage IIIA, IIIB, and stage IIIC1 (any pelvic nodal metastasis) cervical cancer. Multivariable analysis was performed for cause-specific survival based on cancer stage.

Results: In the stage IB cohort (n = 8909), stage IB1 tumors were more likely to be adenocarcinoma and low-grade compared to other the groups (P < 0.001). On multivariable analysis, stage IB2 disease was independently associated with a nearly two-fold increased risk of cervical cancer mortality compared to stage IB1 disease (adjusted-hazard ratio [HR] 1.98, 95% confidence interval [CI] 1.62-2.41, P < 0.001). In the stage III cohort (n = 11,733), stage IIIC1 was independently associated with improved cause-specific survival compared to stage IIIB disease (adjusted-HR 0.79, 95%CI 0.74-0.85, P < 0.001). Survival of stage IIIC1 disease significantly differed based on T = stage, (5-year rates: 74.8% for T1, 58.7% for T2, and 39.3% for T3) with a 35.3% difference in absolute survival (P < 0.001).

Conclusion: The 2018 FIGO staging system for cervical cancer is useful to distinguish survival groups; stage IB1 and stage IB2 disease have distinct characteristics and survival outcomes, while survival in stage IIIC1 varies depending on local tumor factors.

Keywords: 2018; Cervical cancer; FIGO; International Federation of Gynecology and Obstetrics; Staging; Validation.