Purpose: Repeated follow-up imaging examinations for indeterminate pulmonary nodules can have a large impact on patient outcomes, radiation risk, and healthcare costs through resource utilization and physician burden. A pre-existing lung cancer model was used to assess comparative effectiveness and cost-effectiveness of an older follow-up program with standard Fleischner Society guidelines for management of pulmonary nodules, including and in the absence of screening.
Method: The Lung Cancer Policy Model (LCPM) is a microsimulation model that simulates individuals’ lung cancer development, progression, detection, follow-up, and survival, while accumulating healthcare-related costs. Benign pulmonary nodules and risks of radiation-induced lung cancer from imaging exams are also simulated. Patients with CT or CXR-detected nodules (4-8mm diameter) undergo follow-up CTs at 1-, 3-, 6-, 9-, 12-, and 24-months. Using the LCPM, trial runs of 500,000 individuals born in 1930 (with US-representative smoking histories) were conducted utilizing the old follow-up program and a newly designed program based on Fleischner Society’s recommendations. The baseline risk factor threshold (5 pack-years) in the Fleischner guidelines was varied to include 10, 20, and 30 pack-years. All programs were simulated with no screening, as well as with 1, 3, and 10-CT screen programs at yearly intervals beginning at age 65. We compared the outcomes of the various follow-up protocols on the basis of life-years saved and healthcare-related costs.
Result: In the absence of screening, the older follow-up program was strictly dominated by the Fleischner Society guidelines (all thresholds), which yielded 93,187 additional life years and reduced costs by over $996 million (baseline threshold, cohort size of 500,000). The total number of CTs for the cohort was reduced by 5.7% (422,763 to 398,684) by switching to the Fleischner follow-up. Fleischner guidelines also strictly dominated the old follow-up in the presence of screening, with gains in LY and more cost-savings (2.4%, 2.8%, and 3.5% decrease in total costs with 1.5%, 1.4%, and 1.3% increase in life-years for 1, 3, and 10-year screening programs respectively).
Conclusion: Follow-up strategies involving targeted management of pulmonary nodules dominate more aggressive strategies with numerous follow-up CTs, particularly in the presence of screening. While compliance to guidelines varies across institutions, models are an effective tool to compare current and hypothetical guidelines for clinical and cost-effectiveness and develop efficient protocols for management of pulmonary nodules.