Utility of the 3-tier grouping system for survival discriminatory ability in stage IIA cervical cancer

Given the improved survival prediction of a tumor size-based 3-tier grouping system for stage IB cervical cancer under the new staging guidelines, this study examined the survival utility of a tumor size-based 3-tier system for stage T2a cervical cancer.

This is a population-based retrospective observational study utilizing the Surveillance, Epidemiology, and End Result Program from 1988 to 2016. Women with stage T2a/N0-1-x/M0-x cervical cancer were grouped by tumor size in a 3-tier system: stage T2a (≤2 cm), T2a (2.1-4.0 cm), and T2a (>4 cm). Survival outcome was examined by non-proportional hazard analysis with restricted mean survival time (RMST) at 5 years.

Among 2449 cases, the most common group was T2a (>4 cm) (n = 1,392, 56.8%), followed by T2a (2.1-4 cm) (n = 783, 32.0%) and T2a (≤2 cm) (n = 274, 11.2%). The median follow-up was 5.2 years. The proposed 3-tier system clearly discriminated survival outcome between the groups: average overall survival time during 5 years of follow-up, 51.0, 47.2, and 43.8 months for T2a (≤2 cm), T2a (2.1-4 cm), and T2a (>4 cm) group, respectively (P < 0.001). Adjusted between-group difference of average overall survival time in the 3-tier system (8.8 months, 95% confidence interval [CI] 6.2-11.3, P < 0.001) was larger compared to the between-group difference in the historical 2-tier system (5.9 months, 95%CI 4.2-7.6, P < 0.001). Women in the T2a (≤2 cm) group were more likely to have longer average overall survival time during 5 years of follow-up compared to those in the T2a (2.1-4 cm) group (3.6 months, 95%CI 1.1-6.1, P = 0.004).

Our study suggests that a tumor size-based 3-tier grouping system may be useful for improved prediction of survival in stage IIA cervical cancer.