Top Line: Does spine SBRT provide a better pain response than conventional palliative radiation?
The Study: At ASTRO 2019, the results of RTOG 0631 showed no improvement in pain control (decrease of 3 points or more in reported pain) at 3 months with SBRT (16-18 Gy x 1) compared to conventional 8 Gy x 1 for painful spine metastases. Another common spine SBRT regimen is 24 Gy in 2 fractions. SC.24 was a randomized trial where patients with painful spine mets (and no prior RT) were randomized to 24 Gy in 2 fractions or conventional 20 Gy in 5 fractions. Minimum pain score was 2 or higher, and there was a fair distribution across the pain score spectrum. The primary endpoint this time around was complete pain response (CR, pain score of 0) at 3 months. Among 229 enrolled patients, SBRT significantly increased the pain CR rate 14→ 36%, and that difference was maintained at 6 months (16 vs. 33%). When also looking at partial response, there was still an improvement from 39→ 53% with SBRT. Toxicity was similar between arms including a similar rate of vertebral compression fractures. What a difference a year makes.
TBL: 24 Gy in 2 fraction SBRT provides a >20% absolute improvement in complete pain response compared to 20 Gy in 5 fractions for patients with painful spine metastases. | Sahgal, ASTRO 2020