Would you repeat colonoscopy now for a positive Cologuard in a patient whose adequate-prep colonoscopy 3 years ago showed one sub-centimeter adenoma, with surveillance not due for 7 more years?

Too bad that a Cologuard was done without an indication. Unfortunately, now the patient needs a colonoscopy follow-up.

Yes, a colonoscopy should be offered in this scenario. Although the Cologuard was, in principle, not indicated, a positive interval stool test (FIT, Cologuard, or other) has to be acted upon, especially as more time has elapsed since the baseline colonoscopy. The US Multi-Society Task Force guidelines support this approach (Rex et al., PMID 28600072).