An Economic Analysis of SC24 in Canada: A Randomized Study of SBRT Compared with Conventional Palliative RT for Spinal Metastases

PURPOSE:xx.xx was a multicenter randomized controlled phase 2/3 trial conducted in Canada and Australia. Patients with painful spinal metastases were randomized to either 24 Gy/2 stereotactic body radiotherapy (SBRT) or 20 Gy/5 conventional external beam radiotherapy (CRT). The study met its primary endpoint demonstrating superior complete pain response rates (CRR) at 3 months following SBRT (35%) vs CRT (14%). SBRT planning and delivery is resource intensive. Given its benefits in xx.xx, we performed an economic analysis to determine the incremental cost-effectiveness of SBRT compared to CRT. METHODS:The trial recruited 229 patients. Cost-effectiveness was assessed using a Markov model taking into account observed survival, treatments costs, including retreatment, and quality of life (QoL) over the lifetime of the patient. The EORTC-QLU-C10D was used to determine QoL values. Transition probabilities for outcomes were from available patient data. Health system costs were from the Canadian health care perspective and based on 2021 Canadian dollars (CDN). The incremental cost-effectiveness ratio (ICER) was expressed as the ratio of incremental cost to quality-adjusted life years (QALY). Impact of parameter uncertainty was investigated using deterministic and probabilistic sensitivity analyses. RESULTS:The base case for SBRT compared to CRT had an ICER of $9,040CDN per QALY gained. Sensitivity analyses demonstrated that the ICER was most sensitive to variations in the utility assigned to the "No local failure" ($5,457CDN to $241,051CDN per QALY), adopting low and high estimates of utility) and the cost of the SBRT (ICERs ranging from $7,345 to $123,361CDN per QALY). It was more robust to variations in assumptions around survival and the response rate. CONCLUSIONS:SBRT is associated with higher upfront costs compared to CRT. The ICER shows that, within the Canadian health care system, SBRT with 2 fractions is likely to be cost-effective relative to CRT.