Colon cancer stage 3b but after surgery cea level dropped from 13 to 1.8 what does it mean?

Tumor markers: Cea is a tumor marker it does not occur with all colon cancers but the fact that it dropped so abruptly is a positive sign. The marker has the ability to be used to monitor for recurrence. This does by no means indicates you are done. There are a number of treatments for colon cancer and you should recruit the serviceces of a board certified medical oncologist for an opinion on tx options.

That is good: That is a good thing. We use CEA for surveillance. 1.8 is a very good number. Your docs will follow the CEA now to see if it rises as a way to detect recurrence.