Long-term safety and efficacy of fractionated stereotactic body radiation therapy for spinal metastases

Patients with long life expectancy despite metastatic status might benefit from long-term local control of spinal metastases. Dose-intensified radiotherapy (RT) is believed to control tumor growth better and thus offers longer pain relief. This single-institution study reports on fractionated stereotactic body radiation therapy (SBRT) for spinal metastases in patients with good life expectancy based on performance status, extent of metastases, histology, and time to metastasis. Between 2004 and 2010, 36 treatment sites in 32 patients (median age 55 years; male 61 %; median Karnofsky performance score 85) were treated with fractionated SBRT. The median treatment dose was 60 Gy (range, 48.5-65 Gy) given in a median of 20 fractions (range, 17-33); the median maximum dose to the planning risk volume for the spinal cord (PRV-SC) was 46.6 Gy. All patients suffering from pain prior to RT reported pain relief after treatment; after a median follow-up of 20.3 months, 61 % of treatment sites were pain-free, another 25 % associated with mild pain. In 86 % of treatments, patients were free from neurological symptoms at the time of the last clinical follow-up. Acute grade 1 toxicities (CTCAE 3.0) were observed in 11 patients. Myelopathy did not occur in any patient. Radiologically controlled freedom from local progression was 92 and 84 % after 12 and 24 months, respectively. Median overall survival (OS) was 19.6 months. Patient selection resulted in long OS despite metastatic disease, and dose-intensified fractionated SBRT for spinal metastases was safe and achieved long-term local tumor control and palliation of pain.