Stereotactic body radiation therapy for non-spine bone metastases-a review of the literature

Background: Stereotactic body radiation therapy (SBRT) has the ability to deliver significantly higher biologically equivalent doses (BED) compared to conventional radiation treatment. The main goal of SBRT is to improve local tumor control while reducing pain. The side effects however may be greater than those of conventional treatment. Methods: A review of the literature was conducted and articles pertaining to studies of SBRT in non-spine bone metastases were included. Data on outcomes and toxicities were collected in addition to inclusion and exclusion criteria for each study. Results: A total of 14 studies were included in this review. Very rarely were grade 3 and 4 toxicities reported. Endpoints for the studies varied significantly, which made conclusions of overall local control and progression free survival near impossible. In studies that reported local control rates, these rates were all greater than 85%. Progression free survival varied significantly between studies. Conclusions: Due to the lack of consistency in endpoint definitions, it is difficult to compare outcomes across trials. There is a need for consensus in endpoint definitions.