Long-Term Results of Dose-Intensified Fractionated Stereotactic Body Radiation Therapy (SBRT) for Painful Spinal Metastases

Purpose: To report long-term outcome of fractionated stereotactic body radiation therapy (SBRT) for painful spinal metastases. Methods and Materials: This prospective, single-arm, multicenter phase 2 clinical trial enrolled 57 patients with 63 painful, unirradiated spinal metastases between March 2012 and July 2015. Patients were treated with 48.5 Gy in 10 SBRT fractions (long life expectancy [Mizumoto score <= 4]) or 35 Gy in 5 SBRT fractions (intermediate life expectancy [Mizumoto score 5-9]). Pain response was defined as pain improvement of a minimum of 2 points on a visual analog scale, and net pain relief was defined as the sum of time with pain response (complete and partial) divided by the overall follow-up time. Results: All 57 patients received treatment per protocol; 32 and 25 patients were treated with 10- and 5-fraction SBRT, respectively. The median follow-up of living patients was 60 months (range, 33-74 months). Of evaluable patients, 82% had complete or partial pain response (responders) at 3 months' follow-up (primary endpoint), and pain response remained stable over 5 years. Net pain relief was 74% (95% CI, 65%-80%). Overall survival rates of 1, 3, and 5 years were 59.6% (95% CI, 47%-72%), 33.3% (95% CI, 21%-46%), and 21% (95% CI, 10%-32%), respectively. Freedom from local spinal-metastasis progression was 82% at the last imaging follow-up. Late grade-3 toxicity was limited to pain in 2 patients (nonresponders). There were no cases of myelopathy. SBRT resulted in long-term improvements of all dimensions of the 5-level EuroQol 5-Dimension Questionnaire except anxiety/depression. Conclusions: Fractionated SBRT achieved durable pain response and improved quality of life at minimum late toxicity. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study demonstrates that fractionated SBRT is effective in providing long-term pain relief and improved survival rates for patients with painful spinal metastases. Partial pain response was achieved in some patients at 3 months' follow-up and remained stable up to 5 years. Furthermore, fractionated SBRT resulted in long-term improvements in multiple dimensions of the EuroQol 5-Dimension Questionnaire.