Unfavorable effect of small tumor size on cause-specific survival in stage IIA colon cancer, a SEER-based study.

BACKGROUND

We sought to determine the prognostic role of tumor size on cause-specific survival (CSS) of patients with stage IIA colon cancer.

METHODS

Surveillance, Epidemiology and End Results (SEER) database was utilized to identify patients with stage IIA colorectal cancer (examined lymph nodes ≥12) diagnosed from 1988 to 2003. The prognostic effect of tumor size on CSS was evaluated by univariate and multivariate analyses.

RESULTS

A total of 8775 patients were enrolled in the analysis. The median follow-up time was 109 months. As determined by minimal P value method, tumor sizes of 2.5 and 6.0 cm were used as optimal cutoff value to divide the cohort. The 8-year CSS of colon cancer with tumor sizes ≤2.5, 2.6-6.0, and >6.0 cm was 81.6, 86.2, and 86.7% respectively (P = 0.003). In the multivariate analysis of colon cancer, using ≤2.5-cm tumors as reference, decreased hazard ratio (HR) of CSS was observed in 2.6-6.0 cm (HR, 0.736; 95% confidence interval (CI), 0.599-0.905; P = 0.004) and >6.0 cm (HR, 0.770; 95% CI, 0.619-0.958; P = 0.019) tumors.

CONCLUSIONS

In stage IIA colon cancer, small tumor size represented a subset with decreased CSS. Further studies are merited to validate the unfavorable prognostic role of small tumor size in stage IIA colon cancer.