Rare Case of Severe Pancreatitis Induced by Encorafenib and Cetuximab in BRAF V600E-Positive Colorectal Cancer.

Doublet chemotherapy with encorafenib and cetuximab has demonstrated a survival benefit for BRAF V600E mutation-positive advanced colorectal cancer, which generally has a poor prognosis, as shown in the BEACON CRC trial. We encountered a case of rectal cancer with this mutation, complicated by grade 3 pancreatitis, one month after starting this doublet therapy. Despite aggressive treatment efforts, the pancreatitis led to duodenal ulcer perforation and a fatal intra-abdominal abscess. This case highlights pancreatitis as a rare, but severe, side effect of combination chemotherapy.