Epidemiology of polyps in the rectum and sigmoid colon. Evaluation of breath methane and predisposition for colorectal neoplasia.

The clinical significance of methanogenic bacteria in large-bowel carcinogenesis has not been established so far. As part of a screening study of a randomized population sample of 200 men and 200 women aged 50-59 years, the present breath methane study was designed to gain further information on methane excretion in relation to premalignant colorectal lesions, familial cancer disposition, and dietary fat and fiber. Testing for breath methane excretion did not contribute towards the identification of individuals with premalignant colorectal lesions and therefore should probably not be considered a screening tool.