Prognostic and predictive value of immunoscore in stage III colorectal cancer: pooled analysis of cases from the SCOT and IDEA-HORG studies

Among patients with stage III colorectal cancer (CRC), existing risk stratification on the basis of patient and tumor factors is unable to reliably identify which patients require adjuvant chemotherapy, or what the optimimum duration of treatment is for these individuals.There is an unmet need for biomarkers to address these shortcomings. Pooled analysis of cases from the SCOT and IDEA-HORG studies (12 versus 24 weeks mFOLFOX4/6 or CAPOX after curative-intent resection of stage III CRC) found that immunoscore (IS) was independently prognostic, with prognostic value greater in younger (< 65 years) patients treated with CAPOX, and in DNA mismatch repair proficient disease. IS did not predict benefit from extended duration of adjuvant chemotherapy, although the analysis was underpowered to detect this in the FOLFOX cohort. Adding IS to a model containing all clinical variables significantly improved prediction of disease-free survival regardless of MMR status. The authors conclude that IS is prognostic in stage III CRC treated with adjuvant FOLFOX or CAPOX.