Background : There is debate about the optimal colorectal cancer screening test, partly because of concerns about colonoscopy demand.

Aim : To quantify the demand for colonoscopy with different screening tests, and to estimate the ability of the United States health care system to meet demand.

Methods : We used a previously published Markov model and the United States census data to estimate colonoscopy demand. We then used an endoscopic database to compare current rates of screening-related colonoscopy with those projected by the model, and to estimate the number of endoscopists needed to meet colonoscopy demand.

Results : Annual demand for colonoscopy ranges from 2.21 to 7.96 million. Based on current practice patterns, demand exceeds current supply regardless of screening strategy. We estimate that an increase of at least 1360 gastroenterologists would be necessary to meet demand for colonoscopic screening undergone once at age 65, while colonoscopy every 10 years could require 32 700 more gastroenterologists. A system using dedicated endoscopists could meet demand with fewer endoscopists.

Conclusions : Colorectal cancer screening leads to demand for colonoscopy that outstrips supply. Systems to train dedicated screening endoscopists may be necessary in order to provide population-wide screening. The costs and feasibility of establishing this infrastructure should be studied further.