Colonoscopy surveillance in addition to fecal immunochemical test (FIT) screenings was effective in preventing colorectal cancer (CRC) and reducing its mortality rate, but it was not cost effective compared with FIT screening alone, a study published in the Annals of Internal Medicine has shown.

Evidence suggests that FIT screenings are highly effective in reducing CRC mortality but the overall effect of additional surveillance is unclear. While surveillance may reduce the risk of CRC death, it may drive up colonoscopy demand and cost disproportionate to the benefit it provides.

For this study, researchers utilized the Adenoma and Serrated Pathway to Colorectal Cancer (ASCCA) model to perform microsimulations. The ASCCA, a model that simulates Dutch persons aged 20 to 90 years or death — whichever comes first — estimates that the population is at risk for up to 10 adenomas and serrated lesions each. 

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Simulations included a total of 6 strategies. In the reference strategy, no screening or surveillance was performed. The other strategies included: screening without surveillance; screening with surveillance according to Dutch guidelines; screening with surveillance at 5-year intervals for all persons at increased risk; 5-year surveillance intervals for those at high risk and 10 years for intermediate risk; and 10-year intervals for all persons at increased risk. 

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The data showed that CRC mortality was reduced by 50.4% when screened without surveillance compared with no screening or surveillance.

The addition of surveillance to FIT screening reduced mortality by another 1.7% to 52.1% but also increased the lifetime colonoscopy demand by 62% (from 335 to 543 colonoscopies per 1000 patients), which equated to an extra €68,000 ($80,000) for an increase of 0.9 life-years.

CRC mortality was reduced by 51.8% and colonoscopy demand was increased by 42.7% once the surveillance interval was increased to 5 years compared with screening without surveillance.

An incremental analysis revealed that the incremental cost-effectiveness ratios (ICERs) for screening plus surveillance was higher than the Dutch willingness-to-pay threshold of €36,602 ($43,000) per life-year gained

The authors concluded that while adding surveillance to screening reduces CRC mortality risk, it was not cost effective compared with screening alone as evidenced by the increased colonoscopy demand and exceeded Dutch ICER threshold. The most effective strategy to reduce colonoscopy demand without reducing effectiveness was modeled by the surveillance interval being extended to 5 years. 


1. Greuter MJE, de Klerk CM, Meijer GA, Dekker E, Coupé VMH. Screening for colorectal cancer with fecal immunochemical testing with and without postpolypectomy surveillance colonoscopy: a cost-effectiveness analysis [published online October 3, 2017]. Ann Intern Med. doi: 10.7326/M16-2891