Cancer and "cancer related" colorectal lesions in São Paulo, Brazil.

A series of 832 necropsy specimens were studied grossly with a magnifying lens and all lesions identified were studied microscopically. The age and sex-specific prevalence of adenomatous and hyperplastic polyps is reported and results are compared with those of other populations. A correlation was made between polyps and cancer of the colon and rectum (407 cases). The data suggest that São Paulo is a community in a transitional stage between intermediate and high risk of cancer of the colon. The epidemiologic characteristics of lower rectum cancer are peculiar to some populations and appear unrelated to colon cancer. The black population of São Paulo has a higher prevalence than that reported for African negroes. The data also implicate adenomatous polyps, diverticulosis and hemorrhoids as being probably related diseases.