Serial levels of CA 19-9 and CEA in colonic cancer.

The use of serial carbohydrate antigen (CA) 19-9 assays was assessed by comparison with serial carcino-embryonic antigen (CEA) levels on the plasmas of 53 patients with colorectal carcinoma. The patients had all undergone resection for their primary tumors and in six instances subsequent resections for hepatic metastases. Initial CA 19-9 levels were greater than or equal to 37 U/mL in 22 of the 53 patients (41%) and in 68% of the patients with metastatic disease. Similar trends of serial CA 19-9 and CEA levels were found in 79% of the 53 patients. One patient with initially normal CEA levels had elevated CA 19-9 levels from the start. In ten of the 53 patients (19%), serial CA 19-9 levels remained low despite tumor recurrence or progression, and despite increasing CEA levels above 5 ng/mL. The increasing serial CEA trends predicted recurrence in 88% and increasing CA 19-9 trends in 50% of cases, which was increased to 70% by including trends of CA 19-9 levels below 37 U/mL. Following hepatic lobectomy, both serial CEA and CA 19-9 levels decreased rapidly. Used alone, serial CA 19-9 levels did not appear to be as sensitive as standard CEA in this retrospective study of selected patients.