External Beam Radiation Versus Percutaneous Image-guided Cryoablation for Palliation of Uncomplicated Bone Metastases

Cost Effectiveness of External Beam Radiation Therapy Versus Percutaneous Image-guided Cryoablation for Palliation of Uncomplicated Bone Metastases

Clinical question
Is percutaneous image-guided cryoablation a cost effective method for pain palliation in uncomplicated bone metastatic lesions? How does it compare to external beam radiation and in what combination?

Take-away point
Cryoablation is not cost effective for palliation of uncomplicated bone metastases in the initial setting. However, cryoablation is a potentially cost effective alternative for recurrent pain palliation following external beam radiation therapy.

Reference
Cost effectiveness of external beam radiation therapy versus percutaneous image-guided cryoablation for palliation of uncomplicated bone metastases. Chang, E.M., Shaverdian, N., Capiro, N., Steinberg, M.L., Raldow, A.C. Journal of Vascular and Interventional Radiology (JVIR), Volume 31, Issue 8, 1221-1232.

Study design
Cost effectiveness analysis using a Markov model with 1-month cycles over a lifetime horizon, 2017 Medicare outpatient setting reimbursement as cost estimate, and $100,000 per quality-adjusted life-year as willingness-to-pay threshold. Strategies evaluated included external beam radiation therapy (RT) in single fraction (SF) followed by SFRT, SFRT-ablation, ablation-SFRT, multiple-fraction radiation therapy (MFRT) followed by MFRT, MRFT-ablation, and ablation-MFRT.

Funding source
No funding source was disclosed.

Setting
Academic hospital. University of California Los Angeles, Los Angeles, California.







Figure. Visual synopsis.

Summary

Metastatic lesions to the bone, which is the third most common site of metastatic disease after lung and liver, carry significant morbidities, as 50% of patients would develop poorly controlled pain. Radiation therapy (RT) is a well-established treatment however onset of pain relief may take up to 6 weeks. Percutaneous image-guided cryoablation may be a good alternative given its rapid onset of pain relief but it carries an associated procedural cost. Therefore, a cost-effectiveness analysis is needed to assess the optimal utilization of cryoablation in combination with radiation therapy, whether it be single fraction (SFRT) or multiple fraction radiation therapy (MFRT).

The authors performed a cost effectiveness analysis using a Markov model with 1-month cycles over a lifetime horizon, 9 months as median overall survival, outcome probabilities extracted from medical literature, 2017 Medicare outpatient setting reimbursement and 2016 Agency for Healthcare Research and Quality data as cost estimate, $100,000 per quality-adjusted life-year as willingness-to-pay threshold, and 1 million simulated patients. Strategies evaluated included external beam radiation therapy (RT) in single fraction (SF) followed by SFRT, SFRT-ablation, ablation-SFRT, multiple-fraction radiation therapy (MFRT) followed by MFRT, MRFT-ablation, and ablation-MFRT. SFRT was defined as 8 Gy in 1 fraction. MFRT was defined as 30 Gy in 10 fractions. Ablation-ablation was not included as a treatment strategy given very limited evidence of outcomes following repeated cryoablations.

Using RT-RT as a baseline (SFRT and MFRT for their respective comparisons), RT-ablation was found to be cost effective but not ablation-RT. Tornado analysis, specifically for comparison between SFRT-SFRT and SFRT-ablation demonstrated that the results were most sensitive to probability of return of pain and probability of pain relief after cryoablation. Other important variable dependency included median overall survival. RT-RT remain the most cost-effective for median survival <= 8.7 months for SFRT and <= 7.9 months for MFRT. Ablation-RT became more cost-effective for median survival >= 196.4 months for SFRT and >= 19.8 months for MFRT. RT-ablation was the most cost-effective for median survival in between the above mentioned intervals.

Commentary

The authors in this paper have evaluated in details the cost-effectiveness of percutaneous image-guided cryoablation in the setting of uncomplicated bone metastatic lesions for pain palliation in combination with radiation therapy. With a current median overall survival of 9 months, radiation therapy followed by ablation is the most cost-effective. This information is important for referring clinicians and patient advocates. As the authors have also noted, the analyses were highly sensitive to effectiveness of cryoablation as well as median overall survival. A stratified clinical pathway may be proposed with patients with poor prognosis undergoing radiation therapy followed by radiation therapy while patients with longer expected survival may benefit from ablation followed by radiation therapy with regards to cost-effectiveness. More data from prospective trials, particularly on the pain relief/recurrence rate after cryoablation, as well as ongoing economic and clinical assessment will be needed to further delineate the optimal treatment pathway and modality choice. Clinical decisions in other treatment pathways may benefit from rigorous cost-effectiveness analyses such as this paper presented by the authors.

Post Author
Ningcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute 

@NingchengLi