Clinical Value of Consensus Molecular Subtypes in Colorectal Cancer: A Systematic Review and Meta-Analysis.

Abstract

BACKGROUND\nThe consensus molecular subtypes (CMSs) of colorectal cancer (CRC) capture tumor heterogeneity at the gene-expression level. Currently, a restricted number of molecular features are used to guide treatment for CRC. We summarize the evidence on the clinical value of the CMSs.\n\n\nMETHODS\nWe systematically identified studies in Medline and Embase that evaluated the prognostic and predictive value of CMSs in CRC patients. A random-effect meta-analysis was performed on prognostic data. Predictive data were summarized.\n\n\nRESULTS\nIn local disease, CMS4 tumors were associated with worse overall survival (OS) compared to CMS1 (hazard ratio [HR] = 3.28, 95% confidence interval = 1.27 to 8.47) and CMS2 cancers (HR\u2009=\u20092.60, 95% confidence interval= 1.93 to 3.50). In metastatic disease, CMS1 consistently had worse survival than CMS2-4 (OS HR range = 0.33 to 0.55; progression-free survival HR range = 0.53 to 0.89). Adjuvant chemotherapy in stage II and III CRC was most beneficial for OS in CMS2 and CMS3 (HR range = 0.16 to 0.45) and not effective in CMS4 tumors. In metastatic CMS4 cancers, an irinotecan-based regimen improved outcome as compared to oxaliplatin (HR range = 0.31 to 0.72). The addition of bevacizumab seemed beneficial in CMS1, and anti-EGFR therapy improved outcome for KRAS wildtype CMS2 patients.\n\n\nCONCLUSIONS\nThe CMS classification holds clear potential for clinical use in predicting both prognosis and response to systemic therapy, which seems to be independent of the classifier used. Prospective studies are warranted to support implementation of the CMS taxonomy in clinical practice.