Stereotactic body radiotherapy for painful spinal metastases: a decade of experience at a single institution.

Objective: This study aimed to retrospectively evaluate the efficacy of stereotactic body radiotherapy (SBRT) for pain relief in patients with painful spinal bone metastases (SBMs) and to identify key factors contributing to treatment outcomes.

Methods: The authors conducted a retrospective analysis of adult patients who underwent SBRT for painful solid tumor SBMs between March 2012 and January 2023. During this period, SBRT was performed adhering to the International Spine Radiosurgery Consortium guidelines and international consensus recommendations for target volume delineation. To be included, patients needed to experience persistent pain directly associated with SBMs, warranting regular opioid treatment. Positive pain relief post-SBRT was defined by three criteria: 1) a decrease in the severity of pain; 2) reduction in opioid dosage; and 3) concurrent improvement in daily activities. The revised Tokuhashi score and Spine Instability Neoplastic Score were used to identify crucial factors influencing treatment outcomes.

Results: This study included 377 patients, covering 576 lesions across 759 vertebrae. Of these, 332 lesions showed significant pain relief within 3 months following SBRT. Lower pain relief rates were observed in patients with a revised Tokuhashi score of 0-8 or in patients with diabetes mellitus. In contrast, higher relief rates were linked to treating a single painful SBM in 1 SBRT course, and greater contouring of the involved sectors according to International Spine Radiosurgery Consortium guidelines and international consensus recommendations. The highest pain relief rate was observed in patients with prostate cancer (73.8%), whereas the lowest rate was observed in patients with hepatocellular carcinoma (36.4%). The presence of pre-SBRT vertebral fractures, the dosage and fraction of SBRT, and the use of concurrent systemic cancer therapies or antiresorptive agents, including bisphosphonates and denosumab, did not notably influence the pain relief efficacy of SBRT. Comprehensive medical records 6 months after SBRT treatment were available for only 362 lesions. The overall rate of pain relief observed was 32.6%.

Conclusions: SBRT is an effective treatment approach for managing painful SBMs, achieving a pain relief rate of 57.6% within 3 months and maintaining a rate of 32.6% at 6 months after treatment. The transition to osteoblastic lesions may potentially improve the stability of SBMs, indicated by lower Spine Instability Neoplastic Score, which in turn could extend pain relief management.