the most frequent indicator used to detect recurrence in asymptomatic patients and currently is the most cost-effective test for the preclinical detection of resectable colorectal carcinoma disease
Serial CEA measurements can detect recurrent colorectal cancer (bowel cancer) with a sensitivity of approximately 80%, a specificity of approximately 70%, and can provide a lead time of approximately 5 months.1)
is most useful for the early detection of liver metastasis in patients with diagnosed colorectal cancer
but is of little use in detecting early colorectal cancer:
only 4% of stage 1 cases have a raised CEA, whereas 25%, 44%, and 65% of patients with stage II, III, and IV disease, respectively, had abnormal levels 2)
At a threshold of >5 ng ml−1 the sensitivities for detecting CRC up to 1 and 4 years before clinical presentation were 25% and 13%, respectively, at 95% specificity. At a threshold of >2.5 ng ml−1, sensitivities were 57.5% and 38.4%, respectively, with specificities of 81% and 83.5%3)