Carcinoembryonic Antigen (CEA) is a protein present in various cell types but is notably linked to tumors and fetal development. CEA levels are measured through a blood test, with normal levels being less than 2.5 ng/ml in non-smokers and less than 5.0 ng/ml in smokers. Factors that can elevate CEA levels include smoking, infections, inflammatory bowel disease, liver conditions, and certain benign tumors located in organs where cancer can cause increased CEA levels. Typically, benign conditions do not raise CEA levels above 10 ng/ml.The primary application of CEA is as a tumor marker, particularly for intestinal cancers. The most frequent cancers that cause a rise in CEA are those of the colon and rectum. Additionally, pancreatic, stomach, breast, lung, and specific types of ovarian cancers can also elevate CEA levels. A CEA level exceeding 20 ng/ml before treatment often indicates that the cancer has metastasized. CEA is valuable for monitoring the treatment of tumors with high CEA content. If CEA levels are elevated before treatment, they should return to normal following successful therapy. An increase in CEA levels suggests cancer progression or recurrence. It's important to note that treatments themselves can temporarily raise CEA levels due to the destruction of tumor cells and subsequent release of CEA into the bloodstream.The term "carcinoembryonic" signifies that CEA is produced by certain cancers ("carcino-") and the developing fetus ("-embryonic").
