The spine is a common site of metastasis and a complex site for SBRT given the adjacent spinal cord and the tumor embedded within the bone tissue putting the patient at risk of fracture [161]. SBRT delivers precise, high-dose radiation to the target region while sparing the spinal cord and provides satisfactory efficacy and an acceptable safety profile for spinal metastases. A recent landmark randomized phase 3 trial led by Sahgal et al [162] showed that SBRT delivering 24 Gy in 2 fractions was superior to conventional radiotherapy delivering 20 Gy in 5 fractions for patients with limited painful spinal metastases. They reported an 11% risk of VCF in the SBRT arm and superior complete response rates for pain at 3 and 6 months posttreatment with SBRT [162]. No comparative randomized trials have been performed to establish optimal dosing of spine SBRT. Single-fraction SBRT may result in a higher local control rate than those of the other fractionations, particularly with 24 Gy in 1 fraction. However, high-dose single fraction SBRT comes at the expense of a greater rate of vertebral fracture, which can even approximate 40% [96]. At present, the dose of spine SBRT varies from 18 to 24 Gy in 1 fraction, 24 Gy in 2 fractions, and 24 to 40 Gy in 3 to 5 fractions [95]. A study by Chen et al [163] using normal tissue complication probability modeling suggests that the larger volume of the vertebral segment receiving lower doses is more closely associated with post-SBRT VCF than high dose regions, and technical developments in spine SBRT Vertebral Compression Fractures continue to evolve with respect to mitigating the risk of iatrogenic fracture. Typically VCF secondary to radiation can be managed with a cement augmentation procedure, and there is increasing use of cement augmentation procedures prophylactically to mitigate the risk of iatrogenic VCF [15,164].
Management of Vertebral Compression Fractures PCAs. The spine is a common site of metastasis and a complex site for SBRT given the adjacent spinal cord and the tumor embedded within the bone tissue putting the patient at risk of fracture [161]. SBRT delivers precise, high-dose radiation to the target region while sparing the spinal cord and provides satisfactory efficacy and an acceptable safety profile for spinal metastases. A recent landmark randomized phase 3 trial led by Sahgal et al [162] showed that SBRT delivering 24 Gy in 2 fractions was superior to conventional radiotherapy delivering 20 Gy in 5 fractions for patients with limited painful spinal metastases. They reported an 11% risk of VCF in the SBRT arm and superior complete response rates for pain at 3 and 6 months posttreatment with SBRT [162]. No comparative randomized trials have been performed to establish optimal dosing of spine SBRT. Single-fraction SBRT may result in a higher local control rate than those of the other fractionations, particularly with 24 Gy in 1 fraction. However, high-dose single fraction SBRT comes at the expense of a greater rate of vertebral fracture, which can even approximate 40% [96]. At present, the dose of spine SBRT varies from 18 to 24 Gy in 1 fraction, 24 Gy in 2 fractions, and 24 to 40 Gy in 3 to 5 fractions [95]. A study by Chen et al [163] using normal tissue complication probability modeling suggests that the larger volume of the vertebral segment receiving lower doses is more closely associated with post-SBRT VCF than high dose regions, and technical developments in spine SBRT Vertebral Compression Fractures continue to evolve with respect to mitigating the risk of iatrogenic fracture. Typically VCF secondary to radiation can be managed with a cement augmentation procedure, and there is increasing use of cement augmentation procedures prophylactically to mitigate the risk of iatrogenic VCF [15,164].