Carcinoembryonic antigen (CEA) as prognostic marker in colonic cancer.

Radioimmunoassay for serum carcinoembryonic antigen (CEA) was performed in 49 colonic cancer patients. The test results were positive in 42 patients (85.7%) in whom tumor was present at the time of assay. Preoperatively, CEA level suggested the extent and the prognosis of the disease. Strongly positive CEA test results in such patients correlated with metastatic tumors and poor prognosis. Postoperatively, a positive result for serum CEA indicated presence of residual tumor, while negative results did not exclude residual tumor. Periodic CEA determination in the patients who have undergone resection of colonic cancer may detect tumor recurrence that is at a treatable stage. The data show that patients in whom the immediate postoperative CEA concentration returns to normal have a much lower incidence of recurrent cancer of the colon than patients whose CEA level remains elevated.