The Impact of Colonoscopy Screening Guidelines that Incorporate Precursors in the Serrated Pathway: A Cost-Effectiveness Analysis

Background: In 2012, the U.S. Multi-Society Task Force on CRC published guidelines that include sessile serrated polyps (SSPs) as important new precursors to target during a screening colonoscopy. Previously, adenomas were the only polyp precursor targets of colonoscopy. Objective: The purpose of this study is to estimate the incremental cost-effectiveness ratio for colonoscopy comparing the new guidelines to the former guidelines. Methods: We developed a Markov model for CRC that included three pathways: 1) de novo from colonic epithelium without a polyp precursor, 2) through the adenoma-carcinoma sequence, and 3) through an SSP precursor. Then, we simulated the effect of screening colonoscopy on CRC incidence and mortality applying the new guidelines vs. the old guidelines in a hypothetical US cohort of 100,000 adults who began screening at age 50 and ended screening at age 75. Adults progressed through the model for 50 one-year cycles until death or age 100. Costs for CRC detection and treatment were estimated from a limited societal perspective using Medicare reimbursement data. We calculated the cost per life-year (LY) gained for the new CRC screening guidelines and the old guidelines compared to no intervention. Then we compared the two sets of guidelines to one another. Preliminary Results: CRC screening via colonoscopy in this hypothetical cohort of 100,000 adults using the old guidelines prevented 4,161 new CRC cases and 1,901 deaths. Implementing the new guidelines avoided an additional 452 CRC cases and 178 deaths. The old guidelines resulted in 0.064 LY-gained and an $800 increase in costs per person compared to the natural history of CRC with no intervention, with a cost-effectiveness ratio of $12,500/LY. The new guidelines resulted in 0.068 LY-gained and a $405 increase in costs per person compared to no intervention, with a cost-effectiveness ratio of $5,956/LY. Comparing the new guidelines to the old guidelines, the difference in LY-gained was 0.004, and the difference in costs was -$395 per person. Conclusion: CRC screening that includes evaluation of SSPs may be cost-effective, and potentially cost-saving, compared to prior guidelines.