Shifting the Landscape of Spine and Non-Spine Bone Metastases: A Review of Stereotactic Body Radiotherapy

Both spine and nonspine bone metastases are frequent sites of spread from solid organ malignancies. As bone metastases frequently cause significant morbidity for patients, it is critical to offer a treatment that can achieve rapid and durable symptomatic relief and local control, without being associated with serious risks of toxicity. Conventional palliative radiation therapy has a key treatment component in the multidisciplinary management of these patients; however, over the past decade, it has evolved to routinely deliver high biologically effective doses with precision in the form of stereotactic body radiation therapy. This change in paradigm is a result of the shifting landscape in cancer care, such that short-term pain relief is no longer the sole therapeutic aim for selected patients, and durable symptom relief and local tumor control are the goals. This review discusses the randomized prospective evidence, ongoing trials, approach to surveillance imaging, and treatment delivery for stereotactic body radiation therapy, to both spine and nonspine bone metastases, with a specific section on sacral metastases.