

Radiation was delivered with more » intensity-modulated radiotherapy (IMRT) and prescribed to cover 80% of the planning target volume (PTV) with organs at risk such as the spinal cord taking priority over PTV coverage. Patients were treated to a median dose of 24 Gy (range, 10-40 Gy) in a median of three fractions (range, 1-5). The mean age of patients was 56.8 13.4 years. Twenty-two lesions (25.8%) were treated for recurrence after prior radiotherapy (RT). Materials and Methods: Between April 2008 and December 2010, 85 lesions in 66 patients were treated with SBRT for spinal metastases. We report prospective results of this population at Mayo Clinic. Purpose: Based on reports of safety and efficacy, stereotactic body radiotherapy (SBRT) for treatment of malignant spinal tumors was initiated at our institution. The factors associated with the development of spinal deformity in patient treated for neuroblastoma were: orthovoltage radiation exceeding 3000 rads, asymmetrical radiation of the spine, thoracolumbar kyphosis, and epidural spread of the tumor. Eighteen per cent of 419 children with this malignant disease survived more than five years, and of the survivors, 20 per cent had spinal deformity severe enough to warrant treatment. The deformity was due either to the laminectomy or to the paraplegia acting in conjunction with the radiation. Epidural spread of the neuroblastoma was associated with most of the cases of severe scoliosis and kyphosis.

The post-radiation deformity - both the scoliosis and the kyphosis - progressed with growth, the scoliosis at a rate of 1 degree per year and the kyphosis at a rate of 3 degrees per year. Two kyphotic thoracolumbar curve patterns were identified: an angular kyphosis with a short radius of curvature and its apex at the twelfth thoracic and first lumbar vertebrae, and a thoracic kyphosis with more » a long radius of curvature that extended into the lumbar spine. Of these fifty-six, 50 per cent had post-radiation scoliosis, and 16 per cent had post-radiation kyphosis, most frequently at the thoracolumbar junction, at the time of follow-up. Of seventy-four children who were treated at a mean age of seventeen months for neuroblastoma and survived more than five years, fifty-six had spinal deformity due either to the disease or to the treatment after a mean follow-up of 12.9 years.
