CEA levels at recurrence and metastases; importance for detecting secondary disease

The relation of CEA plasma levels to prognostic factors was studied in 170 patients with various stages of colo-rectal cancer. Several parameters of known relevance for the prognosis were analyzed. Among the patients with involvement of regional lymph nodes at the time of the primary, 53% had a raised CEA value (greater than 5 ng/ml serum) as opposed to 21% when this was not the case (p less than 0.05%). When serosal break-through had occured, 47% of the patients had raised values compared to 21% of those with no serosal break-through (p less than 0.02%). After radical surgery, all patients who remained healthy acquired persistent low plasma CEA, giving the assay a prognostic value. Altogether 20 patients had local recurrences without distant metastases and were thus potential candidates for a re-operation for cure. 70% had raised CEA plasma values, giving the assay a better than expected usefulness in the clinical follow-up, the significance of the difference from operated and healthy patients or healthy control persons being high, p less than 0.001%. The secondary rise in CEA appeared to be unconnected with whether or not the primary tumor had been accompanied by raised plasma CEA. The localization and the histopathological differentiation of the primary tumor seemed to be of less importance for the serum CEA than the dissemination of the tumor.