As reported in JAMA Oncology by Ryu et al, the phase III portion of the NRG Oncology/RTOG 0631 trial showed no benefit in pain relief with use of stereotactic radiosurgery (SRS) vs conventional external-beam radiotherapy (EBRT) in patients with one to three sites of vertebral metastases.
In the multicenter trial, 339 evaluable patients were randomly assigned 2:1 between September 2011 and August 2017 to receive SRS (n = 209) or conventional EBRT (n = 130). SRS was given in a single dose of 16 or 18 Gy to involved vertebral level(s) only, excluding any additional spine levels. Conventional EBRT consisted of 8 Gy given to the involved vertebra plus one additional vertebra located above and below the involved site. Eligibility criteria included: solitary vertebral metastasis; two contiguous vertebral levels involved; or maximum of three separate sites. Each site could involve up to two contiguous vertebral bodies. The primary endpoint was patient-reported pain response defined as a ≥ 3-point improvement on the Numerical Rating Pain Scale (NRPS) at 3 months without worsening of pain at secondary site(s) or use of pain medication.
At baseline, the mean (standard deviation [SD]) pain score at the index vertebra was 6.06 (2.61) in the SRS group and 5.88 (2.41) in the conventional EBRT group.
Pain response at 3 months was observed in 41.3% of patients in the SRS group vs 60.5% of the conventional EBRT group (P = .99). The between-group difference of −19 percentage points (95% CI = −32.9 to −5.5 percentage points) suggested worse pain control in the SRS group.
No between-group difference was found for the mean (SD) change from baseline in pain score at the index site at 3 months (−2.98 [3.34] for SRS vs −3.83 [2.97] for conventional EBRT, P = .07). Among patients with two to three involved spine sites, there were no between-group differences in mean (SD) change in pain score of the secondary index site (−1.50 [3.13] for 24 patients in the SRS group vs −2.64 [4.72] for 11 patients in the conventional EBRT group).
Treatment-related any-grade acute adverse events occurred in 7.7% of the SRS group vs 7.7% of the conventional EBRT group (P = .99) within 3 months; late effects occurred in 5.6% vs 3.4% (P = .38). Treatment-related grade 4 late events occurred in two patients in the SRS group and one in the conventional EBRT group (all sepsis/lymphopenia). At 24 months, the incidence of vertebral compression fractures was 19.5% vs 21.6% (P = .59); no spinal cord complications were observed at 24 months in either group.
The investigators concluded, “In this randomized clinical trial, superiority of SRS for the primary end point of patient-reported pain response at 3 months was not found, and there were no spinal cord complications at 2 years after SRS. This finding may inform further investigation of using spine radiosurgery in the setting of oligometastases, where durability of cancer control is essential.”
Samuel Ryu, MD, of the Department of Radiation Oncology, Stony Brook University Health Science Center, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit jamanetwork.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.