Screening Based on Risk for Colorectal Cancer Is the Most Cost-Effective Approach  Yock Young Dan, Benjamin Y.S. Chuah, Dean C.S. Koh, Khay Guan Yeoh  Clinical Gastroenterology and Hepatology  Volume 10, Issue 3, Pages 266-271.e6 (March 2012) DOI: 10.1016/j.cgh.2011.11.011 Copyright © 2012 AGA Institute Terms and Conditions

Figure 1 Cost/effectiveness analysis of CRC with different strategies. Stool DNA and virtual colonoscopy are dominated (more expensive and less effective). iFOBT had the lowest cost/QALY compared with no screening. Colonoscopy every 10 years had the lowest ICER as evident in the lowest gradient referenced to sigmoid/iFOBT. Barium (Ba) enema, single colonoscopy, and sigmoidoscopy every 5 years with and without annual iFOBT were all categorized under extended dominance of iFOBT and colonoscopy every 10 years. Clinical Gastroenterology and Hepatology 2012 10, 266-271.e6DOI: (10.1016/j.cgh.2011.11.011) Copyright © 2012 AGA Institute Terms and Conditions

Figure 2 (A) Two-way sensitivity analysis of risk of CRC and cost of colonoscopy. Both factors had a major impact on cost effectiveness. When the cost of colonoscopy was less than US$300, colonoscopy was the most cost-effective strategy regardless of risks of CRC. When the cost of colonoscopy exceeded US$300, iFOBT was the most cost-effective strategy at low CRC incidence whereas sigmoidoscopy was more cost effective at higher CRC incidence. (B) Sensitivity analysis of adherence. Assuming secondary and tertiary adherence are the same, strategies that have short cyclic screening are affected more significantly by poor adherence. iFOBT becomes more cost effective than single sigmoidoscopy when adherence is better than 36% and more cost effective than colonoscopy every 10 years when adherence exceeds 50%. (C) Sensitivity analysis of screening age. iFOBT was the most cost-effective strategy for subjects younger than age 60. Because the risk of CRC increases after age 60, a colonoscopy every 10 years became more cost effective. The cost-effectiveness graph increases sharply at age 72 because the benefit of screening is offset by death from other causes. Clinical Gastroenterology and Hepatology 2012 10, 266-271.e6DOI: (10.1016/j.cgh.2011.11.011) Copyright © 2012 AGA Institute Terms and Conditions

Figure 3 Net health benefit of screening strategies. Single sigmoidoscopy or single colonoscopy derive the maximal health benefit at a low willingness-to-pay (WTP) threshold (<$50,000/QALY) and is appropriate for countries with limited spending power. At WTP greater than $50,000, colonoscopy every 10 years is the most effective and averts the most CRC deaths but comes with a price tag of $600 million and requires 1 million colonoscopies. Tailoring a combination of iFOBT and colonoscopy decreases the number of colonoscopies needed and the total cost while achieving an equivalent reduction of CRC deaths. Clinical Gastroenterology and Hepatology 2012 10, 266-271.e6DOI: (10.1016/j.cgh.2011.11.011) Copyright © 2012 AGA Institute Terms and Conditions

Supplementary Figure 1 Clinical and transition states in CRC screening. Clinical Gastroenterology and Hepatology 2012 10, 266-271.e6DOI: (10.1016/j.cgh.2011.11.011) Copyright © 2012 AGA Institute Terms and Conditions

Supplementary Figure 3 Estimated incidence of CRC based on the number of years after a negative colonoscopy. Clinical Gastroenterology and Hepatology 2012 10, 266-271.e6DOI: (10.1016/j.cgh.2011.11.011) Copyright © 2012 AGA Institute Terms and Conditions

Supplementary Figure 4 Validation of projected CRC and CRC deaths based on model compared to actual Singapore cancer and death registry. Clinical Gastroenterology and Hepatology 2012 10, 266-271.e6DOI: (10.1016/j.cgh.2011.11.011) Copyright © 2012 AGA Institute Terms and Conditions