Circulating carcinoembryonic antigen (CEA):

Plasma levels of circulating carcinoembryonic antigen (CEA) were measured by zirconyl phosphate gel radioimmunoassay in 112 patients with chronic inflammatory bowel disease. The levels were then related to category, extent, duration, and severity of disease, as well as to the ages and surgical status of the patients. The distribution of CEA levels and their mean values were significantly raised over the levels in 33 normal control subjects, and were similar among patients with ulcerative colitis compared with those with granulomatous bowel disease. Positive values were defined as those in excess of 2.5 ng/ml. Positive assays occurred in 42% of ulcerative colitis patients, in 38% of Crohn's disease patients, and in 40% of the total group with inflammatory bowel disease. Among normal control subjects, only 3% were positive. Among inflammatory bowel disease patients, positive CEA assays occurred more frequently with more severe disease, more extensive anatomical involvement, younger ages, and shorter duration of disease. Those patients who had undergone total colectomy showed levels of circulating CEA and frequency of CEA positivity similar to those of an age-matched normal control group. Levels of CEA did not correspond with known cancer risk factors in patients with inflammatory bowel disease. Although rising or persisting plasma CEA values unrelated to severity and extent of disease may indicate an unfavourable prognosis in cancer, this study shows that a single CEA value in patients with chronic inflammatory bowel disease is not a reliable indicator of cancer risk.