Why on earth would you do that?     I agree with the advice already given.
Such testing is next to useless, and more likely to do you harm than good
through generating such worries and wholly unnecessary further
investigations.   There is no evidence at all that CEA screening of
unsymptomatic patients will save lives from cancer (and precious little that
it saves lives even in patients already known to have had cancer,  although
it is commonly used by oncologists in that context).       Your doctor is
unwise to be supporting you in this.

Peter Moran

No