How do you treat fit patients with metastatic adenocarcinoma of colon who have progressed on at least 2 prior lines of standard chemotherapy?

The answer to this question depends on the patient's molecular diagnostics and prior therapy. I'll assume FOLFOX/XELOX-bev. If KRAS WT, I'll assume followed by FOLFIRI-EGFRi. If the patient is MSI-H, I would strongly recommend immunotherapy with pembrolizumab based on Le et al, NEJM. If MSS and you can get the patient enrolled on the current cobimetinib/atezolizumab study for MSS patients, then I would recommend that trial over regorafenib or TAS (Lonsurf). In general, I consider trial options b...