A 68-year-old woman with ascending colon cancer was the patient (cT4bN2M1a [LYM] cStage IVA, BRAF V600E mutation-positive, and MSI-high). She was given modified FOLFOXIRI as first-line therapy but did not respond. The infiltration of the primary lesion in the abdominal wall was alleviated, allowing conversion surgery to be performed.