THE IMPACT OF EARLY POSTPOLYPECTOMY SURVEILLANCE ON THE DEMAND FOR COLONOSCOPY

Purpose: The use of colonoscopy as a primary screening test for colorectal cancer (CRC) has increased substantially since 2000.  At the same time there is a growing concern of early post-polypectomy surveillance (i.e., surveillance colonoscopy done at shorter intervals than recommended) and inadequate capacity to meet colonoscopy demand in the next decade.  We used recent screening uptake data to forecast the demand for colonoscopy under various screening and surveillance scenarios and examined the impact of early surveillance on the demand for colonoscopy.

Method: We used a population-based state-transition Markov model to simulate the natural history of CRC and superimposed a screening mechanism than could either identify and remove adenomas or detect and treat CRC.  We used data from the US census to simulate the population 50 years of age and older and projected the demand for colonoscopies and the colonoscopy-related deaths each year. We modeled current screening uptake from the National Health Interview Survey (NHIS), as well as the type of screening (e.g., fecal occult blood testing, colonoscopy). Recommended surveillance intervals are 3 years following polypectomy of an adenoma of 10 mm or larger or more than 3 adenomas, and 5 years for all other findings.  We modeled early surveillance by specifying that a proportion of patients with history of adenomas undergo surveillance before the recommended time interval.   We varied the timing of surveillance colonoscopies to assess its impact on colonoscopy demand.

Result: We estimated the demand for screening and surveillance colonoscopies in 2009, based on the current guidelines and current screening uptake, to be 6.56 million.  Early surveillance resulted in an additional 1.03 million colonoscopies and a 14% increase in colonoscopy-related mortality.  We projected the demand for colonoscopy under current screening practices to reach 12.02 million by 2015 and 13.26 million by 2020 assuming a gradual increase to a 70% screening uptake.  The current estimated capacity in the US would have to increase by 40% to meet the demand.

Conclusion: The projected demand for colonoscopy is expected to surpass the capacity if screening uptake increases.  Early post-polypectomy surveillance represents a relatively large part of the increase in colonoscopy demand, with a substantial impact on colonoscopy-related deaths.  Efforts need to be made to increase colonoscopy capacity and ensure adherence to surveillance guidelines.