O-17 A TNM-Immune (TNM-I) classification staging system for predicting survival in colon cancer in a multicenter international SITC study

Background The present study was performed to evaluate the predictive capacity of the TNM-Immune (TNM-I) classification staging system vs. the 8th edition of the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC) tumor-node-metastasis (TNM8) staging system for survival of patients with colon cancer. Methods Data of eligible patients from the Society-for-Immunotherapy-of-Cancer (SITC) international-consortium from 13 countries were evaluated for the consensus Immunoscore in 3539 patients with AJCC/UICC-TNM stages I-III colon cancer. The primary-endpoint time-to-recurrence (TTR) and secondary-endpoint overall-survival (OS) were evaluated for 2650 patients with complete TNM staging and Immunoscore information. The consensus Immunoscore was predefined and previously published (Pages et al. Lancet 2018), and TNM-I categories (IA to IIID) were performed based on TNM8 plus consensus Immunoscore categories. Results A total of 1737 (64.8%) patients presented stage migration, including 1495 (55.8%) migrating to a lower stage and 242 (9.0%) to a higher stage. In TNM8 stage IIIB, patients migrated to all possible TNM-I stages from IA to IIID. A total of 563 Stage IIIB (67.0%) patients presented stage migration, including 181 (32.1%) migrating to a lower stage and 196 (34.8%) to a higher stage. TNM-I Hazard ratio for TTR between TNM-I stage IA and IIID was HR= 16.9 (95%CI 7.75-36.83), in contrast TNM8 TTR between IA and IIIC was only HR= 12.77 (95%CI 7.99-20.4), all P< 0.0001. TNM-I Hazard ratio for OS between TNM-I stage IA and IIID was HR= 5.95 (95%CI 3.17-11.19), in contrast, TNM8 OS between IA and IIIC was only HR= 3.16 (95%CI 2.38-4.18), all P< 0.0001. The TNM8 staging system exhibited prognostic discrepancies in discriminating stage IIB and IIC and between IIC and IIIA on survival curves from TTR and OS, which were improved in the TNM-I staging system. In cox multivariate analysis, the relative contribution of TNM-I was 90.3% in comparison to gender, sidedness, MSI, grade of differentiation, mucinous colloid, VELIPI. The TNM-I had a better predictive capability of survival, as evidenced by higher likelihood ratio scores, and smaller AIC values for TNM-I compared with those for TNM8 edition. Conclusion Therefore, the present study showed the importance of immuno-pathology and demonstrated that the TNM-Immune (TNM-I) classification staging system is superior (log-likelihood ratio test P< 0.0001) to the 8th edition of the AJCC/UICC-TNM staging system in predicting the TTR and OS of patients with colon cancer.