Stereotactic body radiotherapy is an effective treatment in reirradiating spinal metastases: current status and practical considerations for safe practice

Spinal metastases are a relatively common manifestation in advanced cancer patients. Low-dose conventional radiotherapy has long been the mainstay of treatment under the assumption that patients have a limited life expectancy in the order of 3-6 months. However, with new developments in systemic therapies, patients are surviving longer than expected. As the spinal retreatment rates, secondary to conventional radiation, can approach 20-50%, retreatments are likely to be more frequent. Rather than a second course of even lower-dose conventional radiation, spine stereotactic body radiotherapy (SBRT) has been developed predominantly to overcome the limitations of conventional reirradiation. Spine SBRT permits a second course of high-dose radiation aimed at local tumor control while sparing the spinal cord, and other surrounding normal tissues, of a toxic dose. The focus of this review is to provide an overview of reirradiation spine SBRT, and address key issues surrounding safe and effective practice.