<s>[INST] I had breast cancer a year ago,  CEA was at start 2.5, then 3.0 then3.6, then 3.7 and then 3.8 and now back to 3.3  I had a colonoscopy and all it showed were 3 more precanerous polyps.  I do have extensive divertula, and chronic gastritis.  Is the fact my cea is going down a good sign? [/INST] Hi, dairy have gone through your question. I can understand your concern.  CEA level increased in colon cancer, lung cancer and other tum out of endodermis origin.  Fall in the CEA level is good sign.  However, you should regularly check your CEA level.  And if you have precancerous polyp in colon then you should go for surgery to remove them. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using Chat Doctor. Wish you a very good health. </s>