Evaluation of serum carcinoembryonic antigen monitoring in the follow-up of colorectal cancer patients with metastatic lymph nodes and a normal preoperative serum level.

The value of serial serum carcinoembryonic antigen (CEA) assay in the follow-up of colorectal cancer patients with metastatic lymph nodes and normal (< or = 5 ng/ml) preoperative CEA levels, was examined in this study. Thirty-eight patients were studied and compared with 22 patients with elevated CEA levels. The overall sensitivity of CEA for the diagnosis of recurrence was 36%. Postoperative CEA was strongly influenced by the site of recurrence. CEA monitoring showed the best results in patients who developed hepatic metastases (sensitivity 60%, specificity 94%, positive predictive value 60%, and negative predictive value 94%), and was ineffective for the detection of locoregional or pulmonary metastases. The results indicate that elevation of CEA in the postoperative course of these patients is an indicator of the presence of hepatic metastases. Postoperative CEA monitoring should not be omitted in Dukes C patients with normal preoperative levels, and is more reliable for the detection of liver metastases.