If KRAS status was taken into account, in accordance to OS, a significant difference in PFS associated with primary tumor location was only evident in patients with KRAS codon 12/13 wild-type tumors (4.6 vs. 8.4 months, p = 0.007, HR = 0.54), but not in patients presenting a mutation in these loci. This evidence concerns the gene KRAS and neoplasm.