Abstract

Carcinoembryonic antigen (CEA) has been measured in the faeces of large bowel cancer patients and control subjects to determine whether this measurement might be a useful aid in the diagnosis of large bowel cancer. The mean faecal CEA in 24 cancer patients fell significantly from 10.43 +/- 2.39 micrograms/g pre-operatively to 3.61 +/- 0.72 micrograms/g postoperatively (p less than 0.05). Pre-operative values were not related to either tumour stage or serum CEA. In 20 patients with no known colorectal disease the mean faecal CEA was 5.43 +/- 1.95 micrograms/g which was significantly lower than the mean pre-operative value in the cancer patients (p less than 0.05). In 14 patients with a variety of benign colonic diseases the mean faecal CEA was 7.12 +/- 1.39 micrograms/g which was not significantly different from the mean pre-operative value in the cancer patients. Considerable overlap of values was observed between individual cancer and control patients making the test, as presently carried out, non-discriminatory. If the potential for making the test more cancer specific can be realised, however, faecal CEA determination may permit discrimination between cancer and non-cancer patients at a relatively early stage of disease.