A singular victory.
The Study: The decades-old argument is that, notwithstanding the obvious perk of patient convenience, a single fraction of something like 8 Gy is less durable than a more conventionally-fractionated regimen. And with patients living longer than ever with metastatic disease in the era of immune checkpoint inhibition, durability is a legit concern. This MD Anderson randomized phase 2 trial puts a new spin on the classic single- versus multi-fraction palliative regimen by delivering ablative doses in the single-fraction arm. 160 patients with painful bone mets received the tried and true 3 Gy x 10 versus a size-based stereotactic body radiation (SBRT) regimen of 12 Gy x 1 for mets ≥4 cm or 16 Gy x 1 for mets <4 cm. The primary endpoint of pain response among those receiving treatment per protocol was significantly higher with SBRT not only at 2 weeks (36 → 62%) but also, importantly, at 3 months (49 → 72%) and even 9 months (46 →77%). Pain response was defined here as lack of any: worsening pain score, need for increased dose of narcotics, radiographic progression, or re-irradiation. Also worth noting were the nearly identically-low rates of grade 2-3 toxicities.
Bottom Line: As if you needed another reason to love it, SBRT for painful bone mets is a win/win with hard-to-top patient convenience and safety and more durable pain control. | Nguyen, JAMA Oncol 2019