Congratualtions on the CEA decline.
I would still track CA199, LDH, MCV (a pronounced rise is probably desirable if folate replete) and maybe some others on my list to investigate your response and status thoroughly. It is harder to hit what we don't see. My wife would have been backdoored many times by mutated cells with rogue protein expressions if we didn't do this.
What's really damning about poor diagnostics (e.g. CEA only) is sometimes how little it cost us to improve those extra trends over the basic background treatment. e.g. reversing rapidly exponential CA199 cost us one more tiny generic chemo pill where CEA was stabilized; reversing slowly exponential AFP simply cost us extra vitamin C in the IV (in addition to the existing treatment). Other marker combos or images have been solved by one or (lots) more 5 or 10 cent pills, sometimes with more expensive 25-50 cent ones too.
I view any marker (or scan) going exponential like a nuclear device awry, between the China syndrome and full nuclear detonation. If your doctors won't/can't help on panels and markers, pls talk about the numbers here.
watchful, active caregiver for stage IVb CC since early 2010. immuno"Chemo forever," for mCRC