Role of carcinoembryonic antigen as a marker for colorectal liver metastases

Carcinoembryonic antigen (CEA), a marker for colorectal adenocarcinoma, can monitor disease progression and treatment response. This study aims to determine the accuracy of CEA in the detection and resectability of colorectal liver metastases. Patients with primary colorectal cancer were divided into three groups: resectable hepatic metastases (group 1), unresectable metastases (group 2), and disease-free cases (group 3). The CEA concentration was recorded pre- and post-hepatectomy in group 1 and on radiological confirmation of disease state in the other groups. It was expressed as median (95% confidence interval [CI]), with predictors of concentration determined. Group 1 (n=141) had pre-operative CEA of 8.9 (4.6-13.1), with 38.1% of patients being normal. Maximum tumour diameter correlated with CEA level (r=0.41, P<0.0001). Post-hepatectomy CEA was 2.3 (1.9-2.7; P<0.0001), with 81.1% of patients being normal. Group 2 (n=158) had CEA of 20.6 (9.4-31.9). Group 3 (n=361) had CEA of 2.0 (1.8-2.2). Sensitivity of CEA pre- and post-hepatectomy was 61.2% and 69.3%, respectively, while specificity was 79.8% for both groups. Concentration was elevated in hepatic colorectal metastases but is not a marker of resectability. A CEA reduction post-resection indicates that it may be used as an indicator of treatment response, while CEA is increased by tumour burden and lesion size.