Circulating Antibodies to Carcinoembryonic Antigen Related to Improved Recurrence-free Survival of Patients with Colorectal Carcinoma

This prospective study evaluated the prognostic value of antibodies to carcinoembryonic antigen (anti-CEA), detected by indirect immunosorbent assay, in the serum of colorectal carcinoma patients. Serum carcinoembryonic antigen (CEA) concentrations, measured by electrochemiluminescence immunoassay, were elevated in 26 (37.7%) of 69 patients with colorectal cancer and could not be detected among the 28 patients with benign intestinal conditions or 37 healthy individuals who comprised the control groups. Anti-CEA immunoglobulin (Ig)G or IgM was detected by immunonephelometry in 44 (63.8%) patients with colorectal cancer, three (10.7%) with benign intestinal conditions and four (10.8%) healthy blood donors. Differences in antibody detection frequencies between the cancer patient group and the control groups were statistically significant. Titres of anti-CEA correlated significantly with CEA levels and Dukes' cancer stage. Antibody titre was an independent, significant, favourable predictor for 5-year recurrence-free survival. It is concluded that measurement of serum anti-CEA combined with CEA might be useful as a tumour marker and to assess prognosis. These results need to be confirmed in large, well-controlled, randomized clinical trials.