Carcinoembryonic antigen: its value in the follow-up of patients with colorectal cancer.

We examined the value of carcinoembryonic antigen (CEA) monitoring for detecting treatable recurrence of colorectal carcinoma. CEA assays were undertaken in 193 patients over a 2-year period. The levels in 34 patients were raised in one or more assays above the laboratory-defined upper limit of normal; 31 cases were reviewed retrospectively. In 10% of patients there were Dukes' A lesions at the initial resection, in 39% Dukes' B, and in 52% Dukes' C1 or C2. Tumours were rectal in 61%. Median follow-up was 3 years (range, 16 years-2 months). In 23 of 31 (74%) there were symptoms or signs of recurrent disease prior to or simultaneously with an observed rise in CEA; in 8 the CEA rise preceded the onset of symptoms or the appearance of signs. Of the 31 cases 26 underwent investigation for recurrent disease, but in only 6 of these was the investigation driven by the observed rise in CEA rather than the onset of symptoms or presence of signs. Three of these six were false-positive results (50%), one has been lost to follow-up, and two had confirmed recurrence. Neither of the two with recurrence had operable disease. One of the two had no further treatment, and one underwent laparotomy at which multiple peritoneal seedlings were found. In both of the two cases going to laparotomy, one of which was prompted by a high CEA, widely disseminated disease was found. Over a 2-year period, serial CEA measurement thus yielded no patient benefit.