Surveillance colonoscopy is cost-effective for patients with adenomas who are at high risk of colorectal cancer.

Abstract

Guidelines recommend that patients with colon adenomas undergo periodic surveillance colonoscopy. The purpose of this study was to estimate the cost-effectiveness of these recommendations. We developed a Markov model to study various surveillance strategies from the perspective of a long-term payer. We modeled a cohort of 50-year-old patients with newly diagnosed adenomas, following them until death. Thirty percent of the population was assumed to be at high risk for colorectal cancer. Costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) were measured. Performing colonoscopies every 3 years in high-risk patients and every 10 years in low-risk patients (3/10 strategy) was more costly but also more effective than no surveillance, with an ICER of $5,743 per QALY gained. Compared with this 3/10 strategy, a 3/5 strategy was considerably more costly but only marginally more effective, with an ICER of $296,266 per QALY. A 3/3 strategy was more costly and less effective than a 3/5 strategy (dominated). Results were most sensitive to the annual probability of advanced adenoma formation and the relative risk (RR) of advanced adenoma formation in high-risk versus low-risk patients. Assuming that the probability of advanced adenoma formation was 1.3% per year (base: 0.5%), the ICER of the 3/5 strategy was <$50,000 per QALY gained if the RR of advanced adenoma formation was <2.4 (base: 3.9). Surveillance colonoscopy is cost-effective for patients who are at high risk for developing colorectal cancer. Aggressive surveillance can be expensive or even harmful; efforts should be made to improve risk models for colonic neoplasia.