Bowel Perforation Associated with Robust Response to Braf/Mek Inhibitor Therapy for Braf-Mutant Melanoma: A Case Report

Combination BRAF/MEK inhibition has shown improved response rates and longer progression-free and overall survival for patients with BRAF-mutant metastatic melanoma. A 63-year-old female with widely metastatic BRAF V600E-mutant melanoma was treated with dabrafenib/trametinib. Ten weeks into therapy, she was treated conservatively for a partial bowel obstruction involving a lesion in the distal ileum. She presented two weeks later with CT evidence of a high-grade bowel obstruction with perforation. Emergent surgery was performed. Intraoperative inspection and pathologic analysis of the resected specimen revealed no evidence of melanoma. Seven months postoperatively she is disease free and fully functional. Rapid BRAF/MEK inhibitor-induced regression of small bowel lesions can result in bowel perforation, which is critical to distinguish from the consequences of disease progression.