TNM staging of colorectal cancer should be reconsidered by T stage weighting

AIM:To verify that the T stage has greater weight than the N stage in the staging of colorectal cancer.METHODS:Open data from the Surveillance,Epidemiology,and End Results program were reviewed and analyzed according to the T stage,N stage,and patients’observed survival(OS).The relative weights of the T and N stages were calculated by multiple linear regressions based on their impact on survival.Risk scores for25 TN categories were then calculated from the T and N stage relative weights,and a rearranged tumor node metastasis(TNM)staging system was proposed via a cluster analysis of the TN scores.RESULTS:Both T and N stages significantly affect the OS of patients with colorectal cancer.Moreover,the T stage has greater weight than the N stage in the TNM staging system of colorectal cancer.For colon cancer,the relative T and N stage weights were 0.58 and 0.42,respectively,and for rectal cancer,the relative T and N stage weights were 0.61 and 0.39,respectively.On the basis of cluster analysis of the TN scores,T1N1a was classified to stageⅠ,and T2N1a-1b and T1N1b-2a were classified to stageⅡin our revised TNM staging system for both colon and rectal cancer.For colon cancer,T4bN0 was classified to stageⅢa,but for rectal cancer,it was classified to stageⅢb.CONCLUSION:As the T stage affects colorectal cancer survival more significantly than the N stage,the TNM staging should be revised by relative T stage weight.