I have a 78y male with cecal mass on c-scope, EGD clear. He had right hemicolectomy that showed 7cm invasive adeno, mod diff in Cecum. However 1/28 nodes and 2 peritoneal nodules show poorly diff signet ring adeno, possible second primary. His CT CAP is negative. Would you do anything further to search for a second primary? Also in this age group I typically used FOLFOX/Bev with low threshold for dose reductions because my worry about the 130mg/m2 oxali dose in CapeOx. What is your experience with CapeOx. Do you tweak the dose or schedule in patients at this age to make it more useable?
I personally prefer mFOLFOX over CAPOX, generally, but particularly in a >70 yo population. I think it's reasonable to get a PET and also brain MRI (signet cell has a higher chance of brain mets compared to adenocarcinoma). Would send genomics for somatic mutation testing and MRD status (signatera).
[Community Oncologist Response: Could you explain the benefits of MRD testing here? I believe he still has residual peritoneal disease that is not detected on imaging (seen intra op). Would you recommend just 6 months or long term metastatic therapy?
GI Cancer Specialist Response: MRD testing only in the case of definitive resection and no gross/radiographic evidence of persistent/recurrent disease. Duration of therapy would depend on that as well. If pt had diffuse peritoneal carcinomatosis and 2 nodules were resected with more disease left behind, no role for MRD, and would treat as long term/palliative intent.]
