Radiation in a single fraction of 8 Gy appeared noninferior and less toxic than 20 Gy in multiple fractions to palliate pain in patients with bone metastases, according to results of a multicenter study.
The analysis included 850 patients. Researchers randomly assigned 425 patients to each arm between 2004 and 2012.
All patients had radiologically confirmed, painful bone metastases — defined as ≥2 points on the Brief Pain Inventory scale — and had received prior radiation therapy.
Overall pain response — assessed using Brief Pain Inventory scores and changes in analgesic consumption — at 2 months served as the primary endpoint.
At 2 months, 358 patients assigned 8 Gy radiation in a single fraction and 349 patients assigned 20 Gy in multiple fractions were assessable.
In the overall intention-to-treat population, more patients assigned 20 Gy compared with 8 Gy demonstrated and overall pain response to treatment, although the difference was not statistically significant (32% vs. 28%; P=.21).
In the per-protocol population, 51% of patients assigned 20 Gy had an overall pain response to treatment vs. 45% in the 8-Gy cohort (P=.17).
More patients assigned 20 Gy experienced lack of appetite (66% vs. 56%; P=.011) and diarrhea (31% vs. 23%; P=.018) at 14 days.
More patients in the 8-Gy arm experienced pathological fractures (OR=1.54; 95% CI, 0.85-2.75), and spinal cord or cauda equina compressions (OR=3.54; 95% CI, 0.73-17.15).
“In patients with painful bone metastases requiring repeat radiation therapy, treatment with 8 Gy in a single fraction seems to be noninferior and less toxic than 20 Gy in multiple fractions; however, as findings were not robust in a per-protocol analysis, trade-offs between efficacy and toxicity might exist,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.