Further analysis of the traditionally defined rectal cancer group (with a cut-off of 15 cm from the anal verge) revealed no significant differences in PFS (8.0 months vs 9.3 months, P = 0.136) and DCR (90% vs 90%, P = 0.949) between the left-sided colon and rectum groups under first-line anti-EGFR treatment (Supplemental Tables S4 and S5). This evidence concerns the gene EGFR and rectal cancer.