Considerations regarding the present and future roles of colonoscopy in colorectal cancer prevention.

Effective and safe colonoscopy is essential to colorectal cancer prevention, regardless of the method used for colorectal cancer screening. The level of colorectal cancer incidence reduction provided by colonoscopy and polypectomy varies widely in available studies. There are several mechanisms by which colonoscopy might fail to prevent colorectal cancer, and some of the mechanisms might be overcome by simple currently available measures. Further, advances in colonoscope technology could enhance the effectiveness of colonoscopy or render it less operator-dependent. The large market for colorectal cancer screening in the United States has spawned innovative noncolonoscopic technologies for colorectal cancer and polyp detection. Because these technologies are diagnosis only, their overall impact on outcomes ultimately may be determined by whether they successfully increase adherence to screening (which should reduce colorectal cancer incidence) versus displace patients from colonoscopy screening (which potentially could increase colorectal cancer incidence), as well as their cost effectiveness and the extent to which they reduce colonoscopy complications. As these strategies emerge, monitoring their effects on adherence, cancer prevention, and procedural complications will be needed to optimize their roles relative to primary colonoscopy screening.