The study enrolled 30 patients. mFOLFOX6 or SOX plus cetuximab was administered to 12 patients with the wild-type RAS gene and FOLFOXIRI or SOXIRI to 18 patients with mutant-type RAS. NAC was considered to be a safe, feasible treatment option for LARC. The NAC regimen, effect of NAC, and relative dose intensity of each agent are summarized in Table 2. Doublet chemotherapy (dCT) plus Cmab was administered to all patients with wild-type RAS and triplet chemotherapy (tCT) to all patients with mutant-type RAS. The tumor sizes after the administration of dCT plus Cmab and tCT were 67.1% and 70.6%, respectively, and the response rates of dCT plus Cmab vs. tCT were 66.7% vs. 50.0%, respectively. The proportions of patients with HATE ≥ grade 2 after the administration of dCT plus Cmab and tCT were 50% and 44.4%, respectively.