Dexamethasone Reduces Pain Flare After Palliative Radiotherapy for Bone Metastases
In a Canadian phase III trial reported in The Lancet Oncology, Chow et al found that prophylactic dexamethasone reduced the incidence of radiation-induced pain flare compared with placebo in patients receiving palliative radiotherapy for bone metastases.
Study Details
In this double-blind trial, 298 patients from 23 Canadian sites were randomly assigned between May 2011 and December 2014 to receive two 4-mg dexamethasone tablets (n = 148) or two placebo tablets (n = 150) taken orally ≥ 1 hour before the start of radiation treatment (single 8-Gy dose to bone metastases on day 0) and then every day for 4 days after radiotherapy (days 1–4). Patients had to have a nonhematologic malignancy and pain corresponding to a site of radiologically confirmed bone metastasis.
Patients reported worst pain scores and opioid analgesic intake before treatment and daily for 10 days after radiotherapy. Pain flare was defined as a ≥ 2-point increase on a scale of 0 to 10 in the worst pain score with no decrease in analgesic intake or as a ≥ 25% increase in analgesic intake with no decrease in the worst pain score from days 0 to 10, followed by a return to baseline or lower levels.
Pain Flare
Pain flare during days 0 to 10 occurred in 26% of the dexamethasone group vs 35% of the placebo group (difference = 8.9%, lower 95% confidence bound = 0.0%, one-sided P = .05). Pain flare during days 0 to 5 occurred in 20% vs 31% (difference = 11.1%, lower 95% confidence bound = 2.8%, one-sided P = .03).
The dexamethasone group had a nonsignificantly greater reduction in mean pain score for day 10 vs pretreatment (−2.37 vs−1.85, P = .09). The difference was significant for days 0 to 5 vs baseline (−1.79 vs −1.09, P = .01), with no difference between groups for days 6 to 10 vs baseline.
Adverse Events
Two grade 3 and one grade 4 biochemical hyperglycemic events occurred in the dexamethasone group, with none observed in the placebo group. The most common adverse events of any grade were bone pain (41% vs 48%), fatigue (39% vs 34%), constipation (32% vs 26%), and nausea 23% vs 24%), with most being grade 1 or 2.
The investigators concluded: “Dexamethasone reduces radiation-induced pain flare in the treatment of painful bone metastases.”
Edward Chow, MBBS, PhD, of Sunnybrook Health Sciences Centre, Toronto, is the corresponding author for the Lancet Oncology article.
The study was funded by the Canadian Cancer Society Research Institute. For full disclosures of the study authors, visit www.thelancet.com/journals/lanonc.
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®.
