Social class differences among patients with large-bowel cancer in Cali, Colombia.

The incidence of large-bowel cancer in Cali, Colombia, for 1962-71 shows the upper socioeconomic classes to be a higher risk. This is the first report of a socioeconomic gradient in risk for this site. The gradients were most marked for cancer of the ascending through rectosigmoid colon and were minimal for cancer of the cecum and rectum. The Cali experience presents several parallels with information derived from comparisons of developed and developing countries and also appears consistent with recent information on the possible role of dietary factors in bowel cancer.