Verification Of Increasing The T Stage Weight In TNM Staging System Of Non-metastasis Colorectal Cancer Based On A Nomogram Analysis

Background:Colorectal cancer is one of the most common malignant tumor in the world. The treatment plan of this disease is guided by the AJCC TNM stage of the tumor. We had proposed T-plus staging system which abandon the criterion to discriminate stage Ⅱ/Ⅲ by lymph node status and strengthened weighting of the T stage according to cluster analysis of the summary survival data of SEER. In this study, increasing the T stage weight in TNM staging system of non-metastasis colorectal cancer was verified by single center data with a 25-year follow-up based on Nomogram analysis.Material and Methods:The data of non-metastasis colorectal cancer patients from SEER was used to do the martingale residuals cumulative sum analyze in order to study whether the risk of T stage and N stage changes with time.2080 patients from the database of the cancer center of Zhejiang University were used to construct the Nomogram and establish the Nomo-staging system. The 1,099 patients with colorectal cancer diagnosed before 2005 were analyzed to build a novel staging system based on Nomogram (Nomo-staging system). The remaining 981 patients diagnosed after 2005 were used to test the performance of Nomo-staging system, T-plus staging system and the 7th edition TNM staging system by Akaike information criteria (AIC), Harrell’s c-index and the area under the curve (AUC) of Receiver Operating Characteristic to predict 5-year overall survival. A smaller AIC, higher c-index and higher AUC indicated a better staging system. At last, binomial test was used to test the similarity of Nomo-staging system and T-plus staging system.Results:The actual martingale residuals cumulative sum of both T stage and N stage is higher than the martingale residuals cumulative sum of proportional hazards assumption. The Nomo-staging system was constructed by the data from the cancer center of Zhejiang University. The validation found that the 7th edition TNM staging system showed the weakest performance. For AIC, both Nomo-staging system and T-plus staging system showed smaller value than the 7th edition TNM staging system (3214.912 vs.3224.643 vs.3229.810). For Harrell’s c-index, both the T-plus staging system and Nomo-staging system showed higher value than the 7th edition TNM staging system (0.6814 vs.0.6787 vs.0.6778). For AUC to predict 5-year OS, the T-plus staging system and Nomo-staging system showed slightly higher value than the 7th edition TNM staging system (0.6944 vs.0.6924 vs.0.6913). The P value of binomial test of Nomo-staging system and T-plus staging system was 0.6764, which is not significant.Conclusion:The risk of T stage and N stage of non-metastasis colorectal changes with time. The Nomo-staging system and T-plus staging system had similarity. Both of the two staging systems broke the rule that the positive lymph node is the evidence of stage III. Therefore, it may be reasonable to increase the T Stage Weight in TNM Staging System of Non-metastasis Colorectal Cancer...