High-Intensity Versus Low-Intensity Surveillance for Patients With Colorectal Adenomas: A Cost-Effectiveness Analysis.

Background: Surveillance of patients with colorectal adenomas has limited long-term evidence to support current practice.

Objective: To compare the lifetime benefits and costs of high- versus low-intensity surveillance.

Design: Microsimulation model.

Data Sources: U.S. cancer registry, cost data, and published literature.

Target Population: U.S. patients aged 50, 60, or 70 years with low-risk adenomas (LRAs) (1 to 2 small adenomas) or high-risk adenomas (HRAs) (3 to 10 small adenomas or ≥1 large adenoma) removed after screening with colonoscopy or fecal immunochemical testing (FIT).

Time Horizon: Lifetime.

Perspective: Societal.

Intervention: No further screening or surveillance, routine screening after 10 years, low-intensity surveillance (10 years after LRA removal and 5 years after HRA removal), and high-intensity surveillance (5 years after LRA removal and 3 years after HRA removal).

Outcome Measures: Colorectal cancer (CRC) incidence and incremental cost-effectiveness.

Results Of Base-case Analysis: Without surveillance or screening, lifetime CRC incidence for patients aged 50 years was 10.9% after LRA removal and 17.2% after HRA removal at screening colonoscopy. Subsequent colonoscopic screening, low-intensity surveillance, or high-intensity surveillance decreased incidence by 39%, 46% to 48%, and 55% to 56%, respectively. Incidence of CRC and surveillance benefits were higher for adenomas detected at FIT screening and lower for older patients. High-intensity surveillance cost less than $30 000 per quality-adjusted life-year (QALY) gained compared with low-intensity surveillance.

Results Of Sensitivity Analysis: High-intensity surveillance cost less than $100 000 per QALY gained in most alternative scenarios for adenoma recurrence, CRC incidence, longevity, quality of life, screening ages, surveillance ages, test performance, disutilities, and cost.

Limitation: Few surveillance outcome data exist.

Conclusion: The model suggests that high-intensity surveillance as recommended in the United States provides modest but clinically relevant benefits over low-intensity surveillance at acceptable cost.

Primary Funding Source: National Cancer Institute.