Relative sensitivity of the fecal occult blood test and flexible sigmoidoscopy in detecting polyps.

A group of 1,002 male pattern and model makers, an occupational group at high risk for colorectal cancers, was screened for the presence of polyps and malignancies of the lower gastrointestinal tract. Flexible sigmoidoscopy and serial fecal occult blood testing were both performed on 988 of the participants, and 165 were found to have at least one colorectal polyp. Only 3% of all men with visualized polyps showed Hemoccult-positive stools. Only 2 (4%) of the 51 men with histologically proven adenomatous polyps were Hemoccult positive. Adenomatous polyps of 1 cm or greater in diameter are malignant 8% of the time. This study concludes that the fecal occult blood test sensitivity in detecting colorectal polyps is unacceptably low. It should be supplemented by more rigorous procedures, especially in populations at high risk for colorectal cancer.