ASTRO 2015

Dexamethasone can reduce radiation-induced pain flares

Dr Alysa Fairchild - University of Alberta, Edmonton, Alberta, Canada

Up to 45% of patients who get palliative radiotherapy for bone metastases may experience an acute side effect called pain flare. We think that that’s caused by increased inflammation related to the radiation so dexamethasone is a steroid and we think that that will decrease the inflammation and therefore decrease the likelihood of people getting this side effect.

Have any other studies looked at the use of dexamethasone in this setting?

Our group did do two foundational studies looking at one dose of dexamethasone and three doses of dexamethasone. Those results suggested that it would actually decrease the pain flare incidence.

Can you tell us about the design and methods used in the trial?

Our trail was a double blind randomised placebo controlled phase III trial which took place in 23 Canadian centres. We randomised 298 patients to either dexamethasone or placebo on the same day of their radiation and for four consecutive days afterwards. Dexamethasone was given orally, 8mg one hour prior to radiation and then 8mg orally on each of the successive four days. The main findings for patients where we had complete data, which was a patient completed diary for ten days after the radiation, was that dexamethasone seemed to decrease the number of people experiencing pain flare in the ten days after radiation.

What about the side effects and tolerability of using dexamethasone?

Dexamethasone was surprisingly tolerable. We did measure side effects at day 0, day 10 and day 42 between those people randomised to placebo versus dexamethasone. We found no significant difference in side effects.

Could you comment on the type of radiation used?

Single fraction external beam radiation is very commonly given for painful bone metastases and it’s basically the simplest form of radiation we can give. We have looked at the incidence of pain flare in multiple different doses of this type of radiation and it doesn’t seem as though there’s any difference in the way the radiation is given. We also measured patients’ quality of life in the ten days following radiation and as well at six weeks and we found that at ten days after the treatment people were significantly more functional, with better controlled nausea and better appetite on the dexamethasone arm.

How could these results affect clinical practice?

Given how inexpensive and easy this treatment is we believe that it should become standard of care for patients getting palliative radiotherapy for painful bone metastases because it seems to not only improve pain associated with treatment but also quality of life. We believe that our study results are robust and this is a fairly large sample size across many Canadian centres. So we believe, based on this, that these results are practice changing.

Should dexamethasone be given to all patients or is there a specific group of patients who may benefit?

Ideally it would be nice to be able to predict which of the patients treated with this modality are going to experience a pain flare. At present we’re not able to do that. So we do believe that dexamethasone should be given to everybody undergoing this type of treatment.