Differences in overall survival when colorectal cancer patients are stratified into new TNM staging strategy.

PURPOSE The purpose of this study is to determine whether the prognosis can be more precisely gauged by the revised 6th AJCC staging system and if this is suitable for Korean colorectal cancer patients, and especially for those patients in the Youngdong district. MATERIALS AND METHODS Between September 1996 and December 2003, 365 patients with histologically confirmed colorectal cancer were analyzed. Kaplan-Meier analyses were used to compare the overall and stage-specific 5-year survival. All the statistical tests were two-sided. RESULTS The overall 5-year survival for the entire cohort was 62%. According to the stages defined by the AJCC fifth edition system, the 5-year stage-specific survival was 91% for stage I, 82% for stage II, 51% for stage III and 4% for stage IV. According to the stages defined by the AJCC sixth edition system, the 5-year stage-specific survival was 91% for stage I, 81% for stage IIa, 83% for stage IIb, 100% for stage IIIa, 64% for stage IIIb, 37% for stage IIIc and 4% for stage IV. The 5-year survival was significantly better for the patients with stage IIIb (64%) than those patients with stage IIIc (37%) (p<.001). CONCLUSION It is widely known that the AJCC sixth edition system for colorectal cancer stratifies survival more distinctly than does the fifth edition system by providing more substages. Our study showed that stage IIIb disease had better survival than stage IIIc disease, but we couldn't confirm that this new staging system is relevant in our Korean clinical practice due to the small study population. Therefore, further study is required in a larger population.