325 - Cost-Effectiveness of Stereotactic Body Radiotherapy vs. Thermal Ablation for Primary Renal Cell Carcinoma: Analysis of the FASTRACK II Trial

C. Vargas¹, J. Carrello¹, S. Siva², R. Davey³, M. Bressel⁴, D. I. Pryor⁵, and R. De Abreu Lourenco¹; ¹Centre for Health Economics Research and Evaluation, University of Technology Sydney, Sydney, NSW, Australia, ²Peter MacCallum Cancer Centre, Melbourne, VIC, Australia, ³TROG Cancer Research, Waratah, NSW, Australia, ⁴Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia, ⁵Princess Alexandra Hospital, Brisbane, QLD, Australia

Purpose/Objective(s): FASTRACK II (NCT02613819) was a prospective single-arm trial that demonstrated the safety and efficacy of stereotactic ablative body radiotherapy (SABR) in Australian patients with small, inoperable renal cell carcinoma (RCC). Based on this study, we hypothesized that SABR is less costly and more effective compared to the thermal ablation strategies of radiofrequency ablation (RFA) and cryoablation (CA). Materials/

Methods: We conducted a modelled cost-effectiveness analysis comparing SABR against RFA and CA in patients with RCC who are ineligible for surgery, from an Australian Public Health care system perspective. The analysis applied data from the FASTRACK II trial for SABR and estimates from the literature for the comparator arms. Health-related quality of life (HRQoL) was measured in FASTRACK II using the EORTC-QLQC30 questionnaire and converted to health-state utility values using the QLU-C10D instrument with Australian utility weights. These were analyzed using a mixed model for repeated measures (MMRM), adjusting for age, gender, Charlson Comorbidity Index, ECOG score and tumor size. SABR costs were obtained from linked administrative data records, capturing medical/diagnostic and pharmaceutical services over the trial period. Costs were analyzed using a Generalized Linear Model (GLM), adjusting for health-state, age and time. A Markov model was implemented in R Studio, applying a 10-year time horizon, with patients transitioning between health states that included localized RCC, progression-free, local progression, metastasis, and death. Outcomes were expressed as quality-adjusted life years (QALYs). An incremental cost-effectiveness ratio or ICER (expressed as a cost per QALY gained) would be estimated if costs for SABR exceeded those of the comparator. Deterministic and probabilistic sensitivity analyses were conducted.
Results: The MMRM showed that at all timepoints there was a decrease in HRQoL compared to baseline which was statistically significant at 6, 18, and 33 months. After initial decline, mean scores tended to approach baseline but remained lower. When assessing the domains, the results show that fatigue and dyspnea potentially explain the observed change in QoL. Results for the economic evaluation showed that over a 10-year period, SABR was more effective and less costly compared to RFA and CA, with an average gain of 1 QALY and reducing costs, on average, by approximately AUD $7,000 per patient (Table 1). SABR remained dominant in all deterministic sensitivity analyses undertaken and the probabilistic sensitivity analysis showed that in only 5% of the iterations SABR had a higher cost compared to RFA, but was cost-effective (<$50,000 per QALY).
Conclusion: Our findings show that SABR is a more effective and less costly treatment option compared to RFA and CA in patients with inoperable RCC. From a cost-effectiveness perspective, it should be considered the treatment of choice in this population.