Would you offer additional systemic treatment to a stage II or III resected colon cancer that received 3 months of adjuvant capecitabine/oxaliplatin and now is presenting with a solitary lung metastasis?

Thanks for the question!

First, it is important to clarify whether this lesion developed during or right after adjuvant CAPEOX, if so, there is no point in continuing adjuvant CAPEOX (it is very important to compare with baseline restaging scans performed before starting adjuvant therapy, as solitary lung nodules are common in overall population). If this lesion is a presentation of systemic disease during or right after adjuvant therapy then this would indicate progression of micrometastatic disease to macrometastatic disease and resistance to CAPEOX. If we assume this lesion is not related to prior colon cancer then there is no data for adjuvant CAPEOX beyond 3 months based on the IDEA trial (excluding T4 or N2 + stage III disease which is another discussion). If this solitary nodule developed years after, certainly could consider more platinum depending on the presence or absence of neuropathy...

Secondly, regardless of the timing of the lung nodule as discussed above, initiating workup for the new lung nodule is key. A few important questions to ask; what's the size and location of the nodule (amenable to biopsy?), was there a preceding pulmonary infection or URI, and any increase in tumor markers? Could consider biopsy or short interval scans based on clinical history. If biopsy is indicated but NOT amenable to biopsy and clinical concern is high, could consider tumor-informed ctDNA (understanding limitations of ctDNA in lung mets, negative would not be so assuring but positive would likely be more helpful)...

If the lung nodule is confirmed to be recurrent disease, the next step should be performing NGS and evaluating the patient for other sites of systemic disease. If oligometastatic disease (no other sites of disease), consider starting systemic therapy and thoracic surgeon referral for potential metastasectomy after systemic therapy. If multisite systemic disease, then I would plan sequencing of your systemic therapy based on NGS including clinical trials...

I agree with Dr. Sahin, however, if lung nodule is new and developed more than 12 months from adjuvant therapy, I would suggest ctDNA, followed by surgical resection, then can monitor with ctDNA, if becomes negative then just close monitoring with ctDNA and scans, if positive, would suggest systemic therapy because this is molecular recurrence and its just matter of time to see it on conventional scan, usually its bad prognostic sign.

if lung nodule developed within 12 months of adjuvant therapy or during adjuvant therapy, I would consider disease progression and switch to different therapy depends on NGS panel