How would you treat a patient with metastatic, MSI high, small bowel adenocarcinoma in the frontline setting and after first progression?

This is a really interesting question. If you prefer a more standard approach, I would recommend FOLFOX (I have used bevacizumab in some patients with this cancer, but there isn't great evidence I know of to support use). However, in an MSI-H patient, trying anti-PD-1 therapy sooner rather than later makes sense. Pembrolizumab just recieved (as of 12/13/16) priority review from the FDA for MSI-H cancers. If you can't find a clinical trial for this patient, I would consider pembrolizumab first line, followed by FOLFOX on progression.