CEA

CEA is a cell surface glycoprotein that is useful to monitor patients with persistent recurrent or for metastatic colon cancer. Reported to be positive in 70% cases of colorectal carcinoma , 55% cases of pancreatic carcinoma , 50% cases of gastric cancer, 45% cases of lung cancer , 40% cases of uterine cancer and 25% cases of ovarian cancer. Serum CEA levels are also useful in monitoring the treatment of metastatic breast cancer. CEA elevations have also been reported in benign disorders like alcoholic cirrhosis hepatitis ulcerative colitis ,Crohn’s disease and occasionally in healthy smokers , CEA is neither organ specific nor tumour specific hence CEA levels should not be used for the detection of early cancers. Pre operative CEA levels should be used for predicting prognosis because the level of elevation correlates with the tumour mass . In patients with CEA positives colon cancers. The presence of elevated CEA levels 6 weeks after therapy indicates residual disease. CEA  is useful for detecting recurrence of colon cancer increased levels may precede clinical evidence of recurrence by as much as 6 months. The sensitivity for detecting recurrence is 97% in patients whose CEA was elevated preoperatively , but only 66% in those with normal preoperative levels . Individuals who smoke may have higher  baseline levels  than the non smokers.