Spinal tumors and radiosurgery

Abstract

Spinal tumors epitomize a challenging radiation-treatment paradigm due to the anatomic nature and proximity of the spinal cord. The spine comprises a chain of functional units, with serial-organ-like behavior. Late spinal cord injury or progressive myelopathy may manifest as paresthesias, hyperreflexia, and complete paresis below the irradiated spinal cord segment. Image-guided technology coupled with highly conformal treatment-planning techniques has allowed the safe delivery of tumor-ablative doses of radiotherapy for patients with benign tumors, primary malignant tumors, and spinal metastases. Spinal metastases are more prevalent and radiosurgery results in very high rates of local control for radioresistant metastases. Radiosurgery has been utilized for metastases in the setting of no prior treatment, but also in patients who have recurred after conventional palliative spine radiotherapy and in patients who have required surgical intervention and require postoperative radiation. Higher radiation doses provide better, more durable tumor control, even with hypofractionated regimens. Radiosurgical techniques limit the dose and the volume of normal tissues that are irradiated and treatment is well tolerated. Hence, the rate of severe complications with high-dose hypofractionated spine radiosurgery is extremely low, even when used as salvage therapy in previously irradiated tissue. In complex cases where tumor is located at the dural margin, novel techniques including high-dose intraoperative brachytherapy (i.e.,32P) in conjunction with image-guided radiation therapy offers a significant benefit.​