How would you manage a patient with MSS, KRAS mutated locally advanced rectal adenocarcinoma with a mixed response to neoadjuvant FOLFOX?  

If there is new bone marrow involvement, I assume you confirmed this with a bone marrow biopsy? This would be a very unusual location for rectal cancer, so to speak. If you have not done a BMB, I would obtain pathologic proof of bone involvement. That would make this patient stage IV, in which case,...