149 patients with mechanically stable, non-cord-compressing spinal metastases (166 lesions) were given SBRT in a phase 1-2 study. Patients received a total dose of 27-30 Gy, typically in three fractions. Symptoms were measured before SBRT and at several time points up to 6 months after treatment, by the Brief Pain Inventory (BPI) and the M D Anderson Symptom Inventory (MDASI). The primary endpoint was frequency and duration of complete pain relief. The study is completed and is registered with , number .
Median follow-up was 15路9 months (IQR 9路5-30路3). The number of patients reporting no pain from bone metastases, as measured by the BPI, increased from 39 of 149 (26%) before SBRT to 55 of 102 (54%) 6 months after SBRT (p<0路0001). BPI-reported pain reduction from baseline to 4 weeks after SBRT was clinically meaningful (mean 3路4 [SD 2路9] on the BPI pain-at-its-worst item at baseline, 2路1 [2路4] at 4 weeks; effect size 0路47, p=0路00076). These improvements were accompanied by significant reduction in opioid use during the first 6 months after SBRT (43 [28路9%] of 149 patients with strong opioid use at baseline vs 20 [20路0%] of 100 at 6 months; p=0路011). Ordinal regression modelling showed that patients reported significant pain reduction according to the MDASI during the first 6 months after SBRT (p=0路00003), and significant reductions in a composite score of the six MDASI symptom interference with daily life items (p=0路0066). Only a few instances of non-neurological grade 3 toxicities occurred: nausea (one event), vomiting (one), diarrhoea (one), fatigue (one), dysphagia (one), neck pain (one), and diaphoresis (one); pain associated with severe tongue oedema and trismus occurred twice; and non-cardiac chest pain was reported three times. No grade 4 toxicities occurred. Progression-free survival after SBRT was 80路5%(95%CI 72路9-86路1) at 1 year and 72路4%(63路1-79路7) at 2 years.
SBRT is an effective primary or salvage treatment for mechanically stable spinal metastasis. Significant reductions in patient-reported pain and other symptoms were evident 6 months after SBRT, along with satisfactory progression-free survival and no late spinal cord toxicities.
National Cancer Institute of the US National Institutes of Health.