Colorectal cancer screening: present strategies and future prospects.

Considerable controversy remains as to what represents the most effective and cost-effective approach to screening for colorectal cancer. The American Cancer Society (ACS), whose guidelines are the most widely used in the United States, recommends annual fecal occult blood testing and flexible sigmoidoscopy every 3 to 5 years beginning at age 50 in asymptomatic, average-risk individuals. However, the high rates of false-positive and false-negative results associated with the fecal occult blood testing techniques currently available continue to represent a concern. There is sufficient information to encourage patients and physicians to comply with ACS recommendations for colorectal cancer screening. However, reducing the mortality and morbidity of colorectal cancer will require advances in screening methodology as well as new methods of educating both the public and physicians about the importance of screening. Future screening strategies may include improved fecal occult blood testing, use of colonoscopy (as either a one-time or a periodic examination), and molecular genetic testing performed on feces or blood. Advances in understanding of genetic alterations in colorectal cancer will undoubtedly improve our ability to target aggressive screening strategies and implement preventive measures.