Stereotactic body radiotherapy for non-spine bone metastases: A meta-analysis and international stereotactic radiosurgery society (ISRS) clinical practice guidelines

Abstract

Background

While SBRT to NSBM has become common, particularly in the oligometastatic population, the approach to treating non-spine bone metastases (NSBM) with stereotactic body radiotherapy (SBRT) varies widely across institutions and clinical trial protocols. We present a comprehensive systematic review of the literatures to inform practice recommendations on behalf of the International Stereotactic Radiosurgery Society (ISRS).

Methods

A systematic literature review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies with at least 10 patients receiving SBRT for NSBM were identified and meta-analyses were completed to estimate pooled local control and overall survival rates. Published guidelines on NSBM SBRT were reviewed and consolidated.

Results

There were 25 studies included for qualitative analysis and 18 studies for quantitative analysis consisting of 13 retrospective studies, 2 non-randomized prospective studies, 1 randomized phase 2/3 trial, and a subgroup analysis of a phase I trial. The pooled local control rates at 1 and 2 years were 95 % (95 % CI: 89 %-98 %) and 94 % (95 % CI: 86 %-98 %), respectively. Pooled overall survival rates at 1 year and 2 years were 84 % (95 % CI: 73 %-91 %) and 81 % (95 % CI: 45 %-95 %), respectively. Consensus was reached on recommendations to inform treatment simulation, target delineation, dose fractionation, and anatomic site-specific recommendations.

Conclusion

We present ISRS-endorsed consensus recommendations to inform best practice of SBRT to NSBM, which we found to be efficacious and associated with low rates of adverse events.