Response to first-line treatment (median PFS, 8.0 versus 4.2 months), left-side location of primary tumor (left, 7.9 versus right, 4.9 months), low baseline CEA level (8.0 versus 5.9 months), and no RAS/RAF mutation (9.9 versus 6.4 months) were significant prognostic factors for PFS to aflibercept plus FOLFIRI. This evidence concerns the gene CEACAM5 and neoplasm.