The Role of Serum CEA and CA19-9 in Efficacy Evaluations and Progression-Free Survival Predictions for Patients Treated with Cetuximab Combined with FOLFOX4 or FOLFIRI as a First-Line Treatment for Advanced Colorectal Cancer.

CEA and CA19-9 are useful indicators of therapeutic curative effect from cetuximab combined with first-line chemotherapy. These markers also helped assess cetuximab resistance and served as early predictors of initial treatment effectiveness. Furthermore, a simultaneous increase or decrease in the levels of both indicators was consistent with the observed differences in PFS.