Variability in Steroid Prophylaxis for Radiation-Induced Pain Flare: Practice of Canadian Radiation Oncologists

Dear Editor:

Radiotherapy is an established effective palliative treatment for painful bone metastases. ¹ However, after radiotherapy, ∼40% of patients develop temporary exacerbation of pain at the treated site, known as pain flare. Hird et al. ² performed a qualitative survey of patients with pain flare and found that this had a detrimental effect on their function and mood. In that study, breakthrough analgesia was inadequate, and prophylactic medications were preferred. Patients were hesitant to repeat palliative radiotherapy after experiencing pain flare. Chow et al. ³ demonstrated level 1 evidence supporting the use of dexamethasone prophylaxis in reducing pain flare. Despite this, there is variation in its use. We developed a survey to determine dexamethasone prophylaxis practice when treating bone metastases with radiotherapy, and to explore the factors influencing oncologists' choices. The survey included 30 questions covering demographics of the treating radiation oncologist, their current prophylaxis practice, opinion on importance of prophylaxis, and the impact of cancer and treatment factors influencing their decisions. The survey was sent through e-mail to radiation oncologists who were members of the Canadian Association of Radiation Oncology (CARO) through the SurveyMonkey online platform. McNemars test was used to assess the statistical significance between categories of variables.

This survey was sent to 310 CARO members in July 2018, with a follow-up e-mail three weeks later. One hundred three (33%) responses were received. More than 85% of respondents agreed that radiation-induced pain flare of bone metastases could have a negative impact, particularly as the primary goal of treatment was pain reduction. It was found that Canadian radiation oncologists were more likely to prescribe prophylaxis “always,” “often,” and “sometimes,” after the publication of the Chow study. Baseline pain score played the greatest role in the decision to use prophylactic dexamethasone, with prophylaxis more likely to be prescribed in patients with severe pain (8–10 on a 10-point scale) rather than in patients with mild or moderate pain. This was due to the concern that escalation of pain may lead to a pain crisis, or a lack of analgesic options as patients may already be on multiple and/or high-dose analgesia. When changing from using a single 8 Gy fraction to a 20 Gy in 5 fraction or 30 Gy in 10 fraction radiotherapy regimen, there was a decrease in dexamethasone prophylaxis use, perhaps due to a general belief that pain flare was more likely with larger doses per fraction.

A study by Van Der Linden et al. ⁴ published after completion of our survey, suggested that dexamethasone may not reduce the incidence of pain flare, but may rather postpone its occurrence. Results such as this, along with concerns about the potential harms of dexamethasone, will likely add to the high variability in managing this problem.

In summary, our survey showed variability in Canadian radiation oncologists' pain flare prophylaxis practice. Although consensus has not been achieved, radiation oncologists should discuss with their patients the choice of using dexamethasone prophylactically to reduce the risk of developing pain flare during radiotherapy. ⁵ Further studies of strategies to reduce pain flare are warranted.