Fluorouracil, Leucovorin, and Irinotecan Plus Cetuximab Treatment and <i>RAS</i> Mutations in Colorectal Cancer

In the first-line treatment of mCRC, patients with RAS wild-type tumors derived a significant benefit from the addition of cetuximab to FOLFIRI; patients with RAS tumor mutations did not. Molecular testing of tumors for all activating RAS mutations is essential before considering anti-epidermal growth factor receptor therapy, thereby allowing the further tailoring of cetuximab administration to maximize patient benefit.