Beyond the conventional role of external-beam radiation therapy for skeletal metastases: new technologies and stereotactic directions.

BACKGROUND: Radiation therapy is a common and effective treatment modality in the management of skeletal metastases. Recent advances in technology permitting delivery of an ablative radiation dose with an image-guided stereotactic approach improve the therapeutic threshold. METHODS: The authors reviewed the literature on conventional external-beam radiation therapy and summarized the emerging data about image-guided stereotactic body radiation therapy (SBRT) for vertebral oligometastasis. RESULTS: Pain control can be achieved effectively with conventional external-beam radiation therapy and may be further improved with image-guided spinal SBRT. Image-guided SBRT allows delivery of an ablative radiation dose with minimal toxicity, may potentially improve local tumor control, and may enhance clinical outcomes for histologies that are considered radioresistant. However, further understanding of long-term normal tissue toxicity is lacking. CONCLUSIONS: Radiotherapy options are expanding for patients with skeletal metastases. Image-guided spinal SBRT can deliver a safe ablative radiation dose to improve pain control and potentially local tumor control. Randomized clinical trials are ongoing to assess clinical benefits and outcome with spinal SBRT.