A steroidal pain-management treatment used during radiation therapy for bone metastases has made good on its earlier promise, meaningfully outperforming placebo in a double-blind, randomized phase 3 trial.

Prophylactic ingestion of the steroid, dexamethasone, led to a reduction in episodes of pain flare versus placebo—as well as less severe pain when it did occur—in 298 patients enrolled in the study between 2011 and 2014 from 23 centers throughout Canada.

The results of the new study were presented Sunday at the annual meeting of the American Society for Radiation Oncology (ASTRO) in San Antonio.

The study report, lead authored by Edward Chow, MBBS, of the University of Toronto, notes that radiation therapy for bone metastases often brings on pain flares—temporary but distressing pangs that elevate patients’ pre-treatment levels of discomfort.

During the trial, patients to be treated with radiation therapy for one or two bone metastases were randomized into two groups, one of 148 patients and the other of 150.

Patients in the dexamethasone group took the drug at least one hour before the start of radiation therapy in 8 mg doses for five days beginning on the first day of the therapy. The other group received an oral placebo in the same regimen.  

The dexamethasone group experienced pain flare at a rate of 26.4 percent (39 patients).

The placebo group’s pain-flare rate was 8.9 percent higher, at 35.3 percent (53 patients).

Pain flare was defined as at least a two-point increase in patient-rated worst pain on a questionnaire scale of 0-10, with no decrease in analgesic intake; or a 25 percent or greater increase in analgesic intake with no decrease in the worst pain score from days 0-10.

The research team further observed that, at 10 days post-treatment versus baseline, the dexamethasone patients did better than the placebo patients in overall functioning, as well as in desiring and tolerating food without serious nausea.

Their study report references nine previous studies documenting the incidence of pain flare at a rate of 30 percent to 40 percent of patients treated with palliative radiotherapy to painful bone metastases.

“[O]ur observations of reduced incidence of pain flare and an associated improvement in quality of life scores in nausea, functional interference and appetite lead us to conclude that prophylactic use of dexamethasone should be adopted as standard of care for patients receiving palliative radiotherapy for treatment of painful bone metastases,” they write in their discussion section.

Alysa Fairchild, MD, a co-author of the study and a radiation oncologist at the Cross Cancer Institute and University of Alberta in Edmonton, added in a statement:

“The potential side effects of radiation treatment for bone metastases can be well managed in the majority of people, and therefore pain flare should not be viewed as a barrier to receiving this highly effective therapy for symptom control.”

The study appeared in The Lancet Oncology Oct. 18 to coincide with the start of the ASTRO conference.