Gastrointestinal tract cancer screening using fecal carcinoembryonic antigen.

There is a great need to detect gastrointestinal tract cancer at an early stage. It is well known that most carcinoma tissues of the gastrointestinal tract contain carcinoembryonic antigen (CEA). Stools are a rich source of cells derived from the gastrointestinal tract. We analyzed total fecal CEA in 60 gastrointestinal tract cancer patients, 20 benign gastrointestinal tract disorder patients, and 240 normal controls, using a simple, reliable method. We compared the sensitivity and specificity of fecal CEA with those of serum CEA and fecal occult blood test (FOBT). The level of fecal CEA in gastrointestinal tract cancer was much higher than controls (44.1 +/- 70.1 ng/mg stool vs 3.7 +/- 3.5 ng/mg stool, p < 0.001) and was not increased in benign gastrointestinal disorders (4.5 +/- 8.2 ng/mg stool). Fecal CEA level was > 10 ng/mg stool in 22 of 32 samples (69%)from stomach cancer patients and 24 of 28 samples (86%)from colorectal cancer patients. The sensitivity of serum CEA (> 5 ng/ml) was 19% in stomach cancer and 39% in colorectal cancer, whereas the sensitivity of FOBT was 13% in stomach cancer and 21% in colorectal cancer. The specificity of fecal CEA was 90% in benign gastrointestinal tract disorders and 93% in normal controls. This specificity was similar to those of serum CEA and FOBT. In conclusion, fecal CEA measurement is superior to serum CEA or FOBT for detection of gastrointestinal tract cancer. Fecal CEA may become the screening test of choice for gastrointestinal tract cancer.