Rationale and objectives: 18-Fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET) is effective but costly in the early detection of recurrence for nasopharyngeal carcinoma (NPC) in patients after treatment. In this study, we developed a decision tree model to analyze the cost utility of 18F-FDG PET in detecting loco-regional recurrences for NPC patients after therapy.
Materials and methods: The analysis for cost utility is based on the decision-tree model for three different strategies: 1) magnetic resonance imaging (MRI)-only, 2) PET-only, and 3) MRI-PET (performing PET if MRI result is uncertain). Sensitivity analyses have been performed to examine changes in the cost ratio of PET/MRI and the probability of uncertain MRI.
Results: After inputting the data for utilities and life expectancies into the decision tree model, the quality-adjusted life expectancies turn out to be 16.16 quality-adjusted life-years (QALYs) for strategy 1, 16.70 QALYs for strategy 2, and 17.35 QALYs for strategy 3. The additional cost per additional QALYs for strategy 3 relative to strategy 1 is calculated to be US $462. Strategy 3 dominates over strategy 2 because strategy 3 costs less and yields more QALYs than strategy 2. If the cost ratio of PET/MRI is less than 1.85 or the probability of uncertain MRI is greater than 73%, then the PET-only strategy becomes more cost-effective than the MRI-PET strategy.
Conclusion: Our analysis shows that the MRI-PET strategy is the most cost-effective for now. It is likely the PET-only strategy will become the most cost-effective for recurrent NPC in patients in the near future as the cost of PET has decreased in a faster rate than the cost of MRI.