Competing Nomograms Help In The Selection Of Elderly Patients With Colon Cancer For Adjuvant Chemotherapy

Purpose The extent to which>70 years patients with colon cancer benefit from adjuvant chemotherapy in the presence of competing risks remains controversial.Methods 18937 patients>70 years old with high-risk stage Ⅱ and stage Ⅲ colon cancer were retrospectively reviewed from SEER database.Propensity score matching(PSM)was used to adjust for potential baseline confounding.The nomograms were developed based on the competing model to describe the individual probability of colon cancer-specific death(CCSD)and non-CCSD.The subpopulation treatment effect pattern(STEPP)was used to estimate the treatment-effect heterogeneity.Results In the high-risk stage Ⅱ subgroup,compared to the non-recipients,the hazard ratios(HR)of overall mortality for recipients was 0.83(P = 0.001).The subdistribution hazard ratio(SHR)of CCSD for receipts was 1.22(P = 0.021).The SHR of non-CCSD was 0.63(P<0.001).In the stage Ⅲ subgroup,compared to non-recipients,the HR of the overall mortality for the recipients was 0.62(P<0.001).The SHR of CCSD was 0.77(P<0.001).The SHR of non-CCSD was 0.58(P<0.001).The chemotherapy efficacy differed significantly by risk score of non-CCSD(non-CCSD-RS)(P<0.001).Recipients with high non-CCSD-RS had a rate of CCSD comparative to that of non-recipients(SHR:0.90,P = 0.150)in the stage Ⅲ subgroup.Conclusions A survival analysis based on the overall mortality did not correctly interpret the effect of chemotherapy.Adjuvant chemotherapy did not provide an additional benefit to patients with high-risk stage Ⅱ or patients with stage Ⅲ at high risk of non-cancer death.