Conventional external beam radiotherapy (EBRT) may be more effective than stereotactic radiosurgery (SRS) for reducing pain in cancer patients with spine metastases, according to research published in JAMA Oncology.
At 3 months, patients who received EBRT were more likely than those who received SRS to have an improvement in pain response. Pain response was defined as at least a 3-point improvement on the Numerical Rating Pain Scale (NRPS) without the use of pain medication or worsening at a secondary site.
These results come from the phase 3 NRG Oncology/RTOG 0631 trial (ClinicalTrials.gov Identifier: NCT00922974). The trial included 339 patients with 1 to 3 sites of spine metastases. Most patients (76.7%) had 1 site of vertebral metastasis, and 87.3% received pain medication.
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The patients were randomly assigned 2:1 to receive SRS (n=217) or EBRT (n=136). SRS was administered as a single dose of 16 Gy or 18 Gy given to the involved vertebral bone. EBRT was administered as 8 Gy given to the involved vertebra plus 1 additional vertebra above and below.
The primary endpoint was patient-reported pain response at 3 months at the index vertebral level using the NRPS. At that time, 41.3% of patients who received SRS and 60.5% of patients who received EBRT experienced a pain response (1-sided P =.99; 2-sided P =.01).
The researchers noted that the proportion of SRS recipients who experienced pain relief was half of what was expected based on prior experiences at single institutions.
“It is not clear whether this lower response can be attributed to patient selection, inclusion of occult spine metastases, or study conduct differences as compared with the other reports,” the researchers wrote.
The researchers also found no difference between SRS and EBRT when it came to the appearance of new metastases (43.5% and 43.9%, respectively; P =.96) or progression of known metastases (34.0% and 42.3%, respectively; P =.12).
Likewise, there was no difference in survival between the groups. At 12 months, the survival rate was 44.3% for the SRS group and 53.1% for the EBRT group. At 24 months, the survival rate was 31.5% for both groups (hazard ratio, 0.91; 95% CI, 0.69-1.20; P =.51).
“[T]hese results demonstrate prospectively that 1-year and 2-year survival rates of patients with spine metastases treated with SRS are encouraging and underscore the need to continue to find the optimal SRS radiation dose and fractionation for patients experiencing vertebral metastases,” the researchers concluded.
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Ryu S, Deshmukh S, Timmerman RD, et al. Stereotactic radiosurgery vs conventional radiotherapy for localized vertebral metastases of the spine: Phase 3 results of NRG Oncology/RTOG 0631 randomized clinical trial. JAMA Oncol. Published online April 20, 2023. doi:10.1001/jamaoncol.2023.0356
