Colon cancer overview.

The scope of current prevention research support by the National Cancer Institute includes the clinical assessment of dietary modifications and cancer screening trials, epidemiologic studies, development of new chemopreventive therapies, and the use of advanced molecular biologic technologies to probe the genetic determinants of colorectal adenomas. Colorectal cancer frequently has been associated with high-fat low-fiber diets in epidemiologic and experimental studies. A recently initiated Phase III Dietary Intervention Study of Recurrence of Large Bowel Adenomatous Polyps will investigate the potential benefits of a low-fat high-fiber fruit-and-vegetable-enriched eating pattern to decrease the polyp recurrence rate. The Chemoprevention Program currently is supporting four Phase III controlled clinical intervention trials investigating the cancer-inhibiting effects on colorectal cancer of beta-carotene, piroxicam, calcium, and calcium plus fiber in persons with previous adenomas. A proposed early detection trial will screen for colorectal, prostate, lung, and ovarian cancers. A comparison of incidence and mortality trends indicates progress in colorectal cancer detection and therapy.