Methods: We developed a decision-analytic Markov model to simulate lifetime costs and survival for 65-year-old men with <4-cm unilateral renal cell carcinoma. Two treatment strategies were considered: RFA and NSS. The model incorporates tumor presence, treatments, success rates (local control), costs, complications, and outcomes. The impact of changes in treatment effectiveness, cost, and other key parameters on results was addressed by re-evaluating outcomes as these parameters were varied. Threshold analysis was performed to determine the annual probability of post-RFA local recurrence below which NSS would not be “cost-effective” using a $75,000/QALY willingness-to-pay threshold.
Results: Under base case assumptions, NSS was more effective and expensive than RFA. NSS had an incremental cost-effectiveness ratio of $148,000/QALY relative to RFA, exceeding assumed societal willingness to pay. Below an annual post-RFA local recurrence probability of 0.0043 (0.43%), RFA was preferred over NSS at the assumed willingness-to-pay threshold. At this recurrence probability, RFA and NSS groups had life expectancies of 9.63 and 9.66 QALYs, and lifetime costs of $116,000 and $119,000, respectively. The annual post-NSS local recurrence probability used in the model was 0.0037 (0.37%). Results were robust to changes in most model parameters, but sensitive to NSS and RFA short-term costs (including number of RFA sessions required for tumor ablation), post-NSS local recurrence, and patient age.
Conclusions: RFA is preferred over NSS for treatment of small renal cell carcinoma given an assumed societal willingness-to-pay threshold of $75,000/QALY, and provided the annual post-RFA local recurrence probability is below 0.0043 (0.43%). Short-term costs, post-NSS recurrence, and patient age also impact the relative cost-effectiveness of each strategy.