Cost-Effectiveness of Radiofrequency Ablation (RFA) Versus Stereotactic Body Radiotherapy (SBRT) in the Treatment of Localized Renal Cell Carcinoma

Abstract

Alternative organ preservation strategies for management of localized renal cell carcinoma (RCC) in patients unsuitable for surgery are increasingly being utilized, including radiofrequency ablation (RFA) and more recently stereotactic body radiotherapy (SBRT). We conducted a cost-effectiveness analysis of SBRT versus RFA. A Markov state transition model was constructed for initial local treatment with RFA or SBRT for early stage medically inoperable RCC, defined as node negative T1a/b (≤4 cm or 4-7 cm) lesions. In the model, hypothetical cohorts of early stage, biopsy proven, RCC patients with solitary, unilateral renal masses, and no evidence of distant metastases were created. Transition probabilities, health state utilities and costs used in the model were obtained through a comprehensive literature review of RFA and SBRT for early stage RCC. Incremental cost effectiveness ratios (ICER) were then calculated to compare the two treatments. The analysis was conducted over 5-year time horizon from the perspective of a publicly funded health system in Canada. Secondary analyses were conducted to assess effect of small versus large size (T1a versus T1b) RCC on ICERs. A one-way deterministic sensitivity analysis was conducted. Discounting of 5% was applied. Over 5 years, SBRT gained 4.2 QALYs at cost of $25,342 compared with 3.7 QALYs at cost of $27,634 for RFA. The ICER was $5,048 CAD per QALY in the base case analysis. In patients with small tumors (T1a), SBRT was $6,254 more expensive then RFA and was associated with an additional 0.42 QALYs (ICER $14,963). In patients with larger tumors (T1b), SBRT dominated RFA (i.e. $6,685 less expensive with an additional 0.54 QALYs). In the sensitivity analyses, the greatest potential influencers on cost-effectiveness were the rate of development of distant metastases (0.009-0.055 for SBRT and 0.003-0.025 for RFA) and utility values following both SBRT (0.75-0.85) and RFA (0.65-0.75). Overall, SBRT used as a primary treatment for RCC appears to be more effective at a marginal increase in cost compared with RFA. The use of SBRT appears to be cost-effective for larger tumors while for smaller tumors RFA may be more appropriate as an initial treatment strategy. Potential reasons for increased cost of RFA include equipment costs, costs for complications and admissions in comparison to SBRT> The validity of these conclusions are highly sensitive on the accuracy of local and distant progression rates reported in previous studies, and may be adjusted as the available data on SBRT and RFA continues to evolve and mature.