Dexamethasone for the prophylaxis of radiation-induced pain flare after palliative radiotherapy for bone metastases—a pilot study

Purpose To investigate the efficacy of dexamethasone as a prophylactic adjuvant analgesic to decrease pain flare and to assess its safety and tolerance of dexamethasone. Materials and methods Patients treated with a single 8 Gy for bone metastases took 8 mg dexamethasone before the radiation treatment. The Brief Pain Inventory was administered at baseline and then daily for 10 days after radiation. Pain flare was defined as a two-point increase in the worst pain or a 25% increase in the analgesic intake when compared with the baseline. Results Thirty-three patients (23 males, 10 females) had complete follow-up data. Their median age was 73 years old. Ten patients had progressive worsening pain during the entire 10-day follow-up. A total of eight patients (24%; 95% CI, 10–39%) experienced pain flare during the 10-day follow-up. Two patients had a 1-day pain flare on day 3. Three patients had a 1-day pain flare on day 7. Three other patients had a prolonged pain flare: one had a 3-day pain flare on days 2–4, one had a 3-day pain flare on days 4–6, and the other, a 6-day pain flare on days 3–8. The half-life of dexamethasone is 36–54 h. Only one patient (3%) experienced pain flare in the first 2 days of follow-up with the action of dexamethasone. Dexamethasone was well tolerated. Conclusion Dexamethasone might be effective in the prophylaxis of radiation-induced pain flare after palliative radiotherapy for bone metastases. Randomized trials are required to confirm the finding.