We propose to continue to develop data and understanding on the patterns used as indications for barium enema and to define those patterns which affect the discovery of colon cancer and frequency of false-negative and false-positive studies. This project is designed to develop a better appreciation for the factors that affect the utilization of barium enemas in colon cancer detection in various community settings. We propose to ascertain regional factors that affect the use rates of barium enemas and the reliability of the barium enema in detecting early colon cancer. Hopefully this project will lead to a better definition of patients at risk of colon cancer in order to improve on the early detection of the lesion.