If you're comfy with looking at your own blood tests, we add CEA, CA19-9, CA72-4, LDH for maximium breadth CRC blood test sensitivity, ESR and hsCRP to track and adjust inflammation. Since CA72-4 was negative at the start, we only use it occasionally. LDH5 would be better than (total) LDH but costs extra. The Onco-Sure DR70 fibrogen degradation products test would also add sensitivity, if it is available. The problems are drs lack of experience with multiple markers, transient minor elevations, monitoring continuity, scanxiety and costs.
To me, ideal would be: you get 30 panels and markers tested biweekly or monthly at Walgreen/Walmart/Costco with a finger stick test, $50-$100. Don't even look at it most of the time. They track it and when something gets statistically suspicious, a medico calls you and you're data ready for a productive visit.
Theranos' 30 panel finger stick is already in trial at Walgreens. We can already do the baselines today - at diagnosis, before & after surgery and chemo.