Would you offer a patient with MMR-deficient colon cancer who underwent surgical resection of metachronous liver metastases "adjuvant therapy"?

In the general population of colorectal cancer patients with upfront resectable liver metastatic disease with low clinical risk, resection followed by a risk–benefit discussion regarding adjuvant chemotherapy or surveillance is appropriate. Fluorouracil-based chemotherapy compared to observation has shown improvement in PFS of 6–9% with adjuvant chemotherapy, but no significant improvement in OS at longer term follow-up. (Portier et al., PMID 17075115, Mitry et al., PMID 18794541, Ychou et al., ...

Agree with the above excellent summary. I would discuss the last paragraph with the patient and would suggest the following if no trial is available:

1. If cDNA is negative, just observation and initiation of immunotherapy when demonstrable recurrence.
2. In the likely setting of positive ctDNA, offer Folfox adjuvant and then immunotherapy if progression.