Bile carcinoembryonic antigen levels and occult hepatic metastases from colorectal cancer

PURPOSE: Up to 30 percent of patients will have occult hepatic metastases at the time of curative surgery for colorectal cancer. The ability to predict this group of patients would allow better targeting of appropriate therapy. It has been shown previously that patients with overt hepatic metastases have significantly high levels of carcinoembryonic antigen in gallbladder bile compared with serum levels. The aim of this study was to assess the accuracy of bile carcinoembryonic antigen levels taken at the time of operation in predicting patients with occult hepatic metastases. METHODS: Bile and serum carcinoembryonic antigen samples were collected from 37 patients undergoing surgery for colorectal cancer, 26 of whose procedures were deemed curative and who were followed up for a median of 63.5 months. RESULTS: Twelve patients were alive with no evidence of recurrent disease, and two had recurrent disease, whereas 12 died of disease. The median (interquartile range) serum carcinoembryonic antigen in the disease-free group was 2.8 (1.1-6.1) ng/ml, and in the recurrent group it was 6.35 (4.3-30) ng/ml (P = 0.006), whereas bile carcinoembryonic antigen in the disease-free group was 7 (5-39) ng/ml as compared with 31 (5-383.7) ng/ml in the recurrent group (P = 0.210). The accuracy of serum carcinoembryonic antigen in predicting occult hepatic metastases was 77 percent compared with 72 percent for bile carcinoembryonic antigen. CONCLUSION: Intraoperative bile carcinoembryonic antigen levels are no more accurate than serum carcinoembryonic antigen levels in predicting occult hepatic metastases in patients undergoing potentially curative colorectal cancer surgery.