Background: Patients with low-risk papillary thyroid cancer (PTC) who demonstrate an excellent response to initial therapy have a 2% recurrence rate and 100% disease-specific survival within 10 years. Thus, annual surveillance may be excessive. We hypothesized that less frequent postoperative surveillance in these patients is cost effective.
Methods: A Markov discrete time state transition model was created to compare postoperative surveillance tapered to 3-year intervals after 5 years of annual surveillance versus conventional annual surveillance in low-risk PTC patients with negative neck ultrasound and stimulated thyroglobulin less than 2 ng/mL 1 year postoperatively. Outcome probabilities, utilities, and costs were determined via literature review, the Medicare Physician Fee Schedule, and Healthcare Cost and Utilization Project data. Sensitivity analyses were performed to assess areas of uncertainty.
Results: The cost of annual surveillance was $5,239 per patient and yielded 22.49 quality-adjusted life-years (QALYs). The 3-year strategy cost $2,601 less, but also yielded 0.01 less QALYs. Thus, the incremental cost per QALY of annual surveillance was $260,100. Probabilistic sensitivity analysis demonstrated that less frequent surveillance was more cost effective in 99.98% of 10,000 simulated patients. One-way sensitivity analysis revealed that annual surveillance would be cost effective if the total cost of neck ultrasound could be reduced to $23 or less.
Conclusion: Extending postoperative surveillance to 3-year intervals after 5 years of annual surveillance in patients with low-risk PTC with excellent response to therapy is more cost effective than annual surveillance.