1. In this microsimulation model of U.S. patients aged 50-79, high-intensity surveillance following colorectal adenoma provided clinically significant benefits over low-intensity surveillance at acceptable cost.
2. In nearly all evaluated alternative scenarios, the absolute cost-effectiveness of high-intensity surveillance remained under $100,000 per quality-adjusted life-year (QALY) gained. Compared with low-intensity surveillance, high-intensity surveillance cost less than $30,000 per QALY gained.
Evidence Level: 2 (Good)
Study Rundown: Colorectal cancer (CRC) is the 2nd leading cause of cancer death in the United States despite robust evidence pointing toward routine screening as an effective means of decreasing the risk of death through early detection and removal of precancerous adenomas. Current guidelines recommend surveillance after 5-10 years for patients with low-risk adenomas (LRA) and after 3 years for patients with high-risk adenomas (HRA). However, this frequency constitutes a significant strain on resources, prompting discussion regarding cost-effectiveness especially in light of improvements in colonoscopy performance. Previous observational studies have generally neglected the impact of surveillance intensity on risk of cancer death following adenoma resection, and relevant clinical trial results are not expected for several years. Findings from this microsimulation model supported existing guidelines for surveillance frequency for patients with HRAs and served to counterbalance previous modeling studies advocating against surveillance in patients with LRAs. Furthermore, this model suggested that compared to low-intensity surveillance, high-intensity surveillance yields continually increasing returns in the long term at acceptable cost. The main limitation of this study arose as a result of the dearth of long-term randomized trials concerning adenoma recurrence and CRC incidence. Consequently, despite extensive external model validation, it was difficult to accurately predict the course of CRC incidence at an individual level. Additionally, patients with LRAs of atypical topography or histology were not distinguished from their lower-risk counterparts, increasing the group’s overall likelihood of recurrence/incidence and potentially skewing results in favor of high-intensity surveillance.