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What is True about carcinoembryonic antigen (CEA)-a) Useful for screening of Ca. colonb) Gives confirmative evidence of Ca. colonc) Helpful for follow-up after resectiond) Levels decrease immediately after resection of tumore) Tumour size correlates with CEA level and explain in detail?
Carcinoembryonic antigen (CEA)

CEA is produced by fetal gut, pancrease and liver.
It is a glycoprotein.
It can be used as a tumor marker in colorectal cancer (major use) and also in pancreatic, lung, breast, or ovarian carcinoma.
It is also increased in some non-neoplastic disorders, e.g. alcoholic cirrhosis, hepatitis, IBD (CD, UC), smoking, pancreatitis .

Uses of CEA in colon cancer

Screening
Response to surgery after complete surgical resection, CEA should disappear in 6 weeks (not immediatly), Persistant beyond 6 week indicates residual tumor.
Higher level suggests high tumor burden (size) → Prognostic value.
For follow up to see recurrence.


CEA assays lack both specificity and sensitivity → can not be used to confirm the diagnosis.