Top Line: The results of RTOG 0631 were first presented in abstract form at ASTRO 2019.
The Study: Today we bring you the full publication. As a reminder, 339 patients with 1-3 spine mets (could include up to two consecutive vertebral bodies and up to 3 non-contiguous sites) were randomized 2:1 to palliative radiosurgery versus conventional field radiation of 8 Gy x 1. The primary endpoint was at least a 3-point improvement on a 10-point pain scale at 3 months post-treatment. In the final analysis, that was achieved by 41% of patients after radiosurgery and 61% of patients after conventional radiation. Those rates were 58% and 55% at 12 months, though less than half of patients completed pain questionnaires out this far. Acute and late side effects were almost identical at 2 years with no myelitis and a rate of vertebral compression fracture of 20-22% either way. When originally published, the results were a disappointment for the burgeoning field of spine radiosurgery. The thing to remember is that, just like in the lung and basically everywhere else, “radiosurgery” can mean vastly different things depending on how it is prescribed. Here it meant prescribing 16-18 Gy in the target volume with no clear guidance on hot spot or coverage requirements other than mandating no more than 10 Gy to the hottest 0.35 cc of the spinal cord. Conversely, some folks would argue single-fraction isn’t the way the go. Fortunately, the SC.24 trial provided major support for spine SBRT with a significant improvement in complete pain response using a 24 Gy in 2 fractions technique.
TBL:Spine radiosurgery of 16-18 Gy delivered in a single fraction, while safe, is not superior to your tried and true conventional 8 Gy x 1 in eliciting measured pain response. | Ryu, JAMA Oncol 2023
The Study: Today we bring you the full publication. As a reminder, 339 patients with 1-3 spine mets (could include up to two consecutive vertebral bodies and up to 3 non-contiguous sites) were randomized 2:1 to palliative radiosurgery versus conventional field radiation of 8 Gy x 1. The primary endpoint was at least a 3-point improvement on a 10-point pain scale at 3 months post-treatment. In the final analysis, that was achieved by 41% of patients after radiosurgery and 61% of patients after conventional radiation. Those rates were 58% and 55% at 12 months, though less than half of patients completed pain questionnaires out this far. Acute and late side effects were almost identical at 2 years with no myelitis and a rate of vertebral compression fracture of 20-22% either way. When originally published, the results were a disappointment for the burgeoning field of spine radiosurgery. The thing to remember is that, just like in the lung and basically everywhere else, “radiosurgery” can mean vastly different things depending on how it is prescribed. Here it meant prescribing 16-18 Gy in the target volume with no clear guidance on hot spot or coverage requirements other than mandating no more than 10 Gy to the hottest 0.35 cc of the spinal cord. Conversely, some folks would argue single-fraction isn’t the way the go. Fortunately, the SC.24 trial provided major support for spine SBRT with a significant improvement in complete pain response using a 24 Gy in 2 fractions technique.
TBL:Spine radiosurgery of 16-18 Gy delivered in a single fraction, while safe, is not superior to your tried and true conventional 8 Gy x 1 in eliciting measured pain response. | Ryu, JAMA Oncol 2023