Detection of occult liver metastases in colorectal cancer by measurement of biliary carcinoembryonic antigen concentration: a prospective study.

Background: It has been suggested that bile CEA levels could be a sensitive index for the detection of occult liver metastases (LM) in colorectal cancer (CRC) patients. The aim of this study was to determine the potential value of biliary CEA assay in the early detection of occult LM from CRC.

Methods: From 1995 to 1999 biliary and blood CEA levels were determined in three groups of patients undergoing surgery; Group 1 (n = 35) patients with LM from CRC; Group 2 (n = 154) patients with CRC without LM; Group 3 (n = 23) was the control group.

Results: Biliary and serum CEA levels were significantly lower in group 3 than in group 2 (P = 0.008 and P = 0.002) and in group 2 than in group 1 (P = 0.001 and P = 0.005). With a follow-up of 36 months (group 2), 22 patients (14%) developed LM. For 59 patients, the bile CEA level during laparotomy was less than 5 ng/ml and for 95 patients this level was more than 5 ng/ml, 4 and 18 patients respectively developed metachronous LM; we found a difference (P = 0.03) between these two subgroups. When this analysis was performed with regard to the stage of the tumor, we found no difference for the node negative cancer (n = 79) subgroup (P = 0.6), but we found a significant difference for the node positive cancer (n = 75) subgroup (P = 0.01).

Conclusions: Our data suggest that biliary CEA concentrations at the time of resection of the primary tumor cannot be used to identify patients with occult LM in the node-negative CCR subgroup. However, patients with node-positive CCR and bile CEA level under 5 ng/ml developed LM in only 3% of cases; it might be therefore, possible to use that as a discriminant in situations where the risk of LM is small.