The possible role of the carcinoembryonic antigen (CEA) and other carcinofetal antigens in maligant and benign diseases of the gastrointestinal tract.

In the present review we have discussed antigens, principally the CEA, which have their well defined place in the clinical management of the (malignant) diseases of the gastrointestinal tract. Though the immunological diagnosis of neoplasia is one of the research areas where the most effort and hopes are invested, it is also there, that the carcinofoetal antigens have the least usefullness at the moment. However, studies like those undertaken by Edgington and Plow are probably pointing out if not proving, that even relatively simple procedures like further purification of the antigen can improve its tumor specificity and consequently its diagnostical value (1975). Following their results the final verdict is not spoken yet as to whether CEA (or any other CFA) will even be more than an adjunctive tool in the diagnosis of malignant tumors specially those of the G.I. tract. The 0.6% of "false" positives these authors have obtained in their series with their highly purified CEA-S (against the 30% usually seen with classical CEA preparations) are provocative: one will have to discuss the question, on which grounds the decision "false positive" has been reached and whether these cases are not simply "clinically silent", hence true positive observations. The problem then would be shifted away from the CEA test (or any other CFA test) toward the improvement of all the other conventionally employed diagnostical measurements, which should allow the early confirmation--and localization--of a beginning neoplasia, which has been screened out by an immunological test. Until this is not warranted, the CEA test has its definite place and vocation at the present time in the follow-up of the treated cancer patient, whatever therapy he has received.