Barriers to preventive intervention.

A spectrum of colorectal cancer screening studies identified barriers to screening adherence, although definitive and comprehensive conclusions cannot be drawn. Barriers can be intrinsic (demographic, medical, psychological, and knowledge/attitudes/beliefs) or extrinsic (access to health care, health care provider knowledge and motivation, and lifestyle issues). Certain consistent patterns are emerging. Lower adherence is generally seen in persons who have less knowledge and lower perceived risk of colorectal cancer, as well as when health care providers do not recommend screening. Remedies that reduce intrinsic and extrinsic barriers to screening adherence are needed.