SBRT yields positive responses in patients with spinal metastases

Treatment with stereotactic body radiotherapy (SBRT) results in encouraging palliative responses, with >80 percent of patients having initial pain responses and 60 percent durable pain responses, according to a recent study. Dose escalation can help improve initial complete response (CR) rates.

In addition, the following factors may be considered in the absence of pain: performance status, primary history, and age.

In this study, the investigators probed a multi-institutional registry for patients with spinal metastases treated with single-fraction or fractionated SBRT and evaluated potential predictors of local control (LC) and overall survival. They also examined initial and durable pain responses and CR rates by analysing pre- and post-treatment visual analogue scale.

Finally, logistic regression was used to evaluate potential correlations between pain response, biologically effective dose (BED), and fractionation.

Of the 514 lesions in 466 patients treated with SBRT, 209 lesions had information on LC and 104 on pain. The median pain score of patients with symptoms was 6, and the median follow-up was 8.9 months.

The corresponding 1-year overall survival rates were 76.1 percent, 59.1 percent, 54.9 percent, 37.2 percent, and 23.5 percent for patients with 0 to 4 of the following factors (p<0.0001): Karnofsky Performance Score, age, and primary site (lung and/or nonbreast).

LC rates were 79.9 percent at 1 year and 73.6 percent at 2 years. Most patients (n=86, 82.7 percent) had an initial pain response, with a median decline of 3.5 and a CR rate of 47.1 percent. More than half of the patients (n=65, 62.5 percent) had a durable pain response, with a median decline of 2 and a CR rate of 20.2 percent.

Of note, higher initial CR rates were noted with BED₁₀ ≥51 Gy₁₀ (58.7 percent vs 37.9 percent; p=0.04).