Similar Pain Outcome With Ibandronate vs Single-Dose Radiotherapy for Localized Metastatic Bone Pain in Prostate Cancer


Key Points

  • Ibandronate and radiotherapy had similar effects on pain at 4 and 12 weeks.
  • No differences in quality of life were observed at 4 and 12 weeks.

In a UK phase III noninferiority trial reported in the Journal of the National Cancer Institute, Hoskin et al found similar effects of single-dose ibandronate and single-dose radiotherapy on localized metastatic bone pain in patients with prostate cancer.

Study Details

In the open-label trial, 470 patients with metastatic bone pain suitable for local radiotherapy from 58 UK centers were randomly assigned between April 2003 and November 2009 to receive  a single intravenous infusion of ibandronate at 6 mg (n = 235) or a single-dose of radiotherapy at 8 Gy (n = 235).

Pain was measured using the Brief Pain Inventory. The primary endpoint was pain response at 4 weeks using World Health Orgznization (WHO) criteria and the Effective Analgesic Score (EAS). The maximum allowable difference was ±15%. Patients without response at 4 weeks were offered the alternative treatment.

Ibandronate was received by 227 (97%) of 235 patients and radiotherapy by 224 (95%) of 235 patients as randomly assigned. Among 26 patients without response on average pain score by 4 weeks, 14 received the alternative therapy. In addition, 114 patients not meeting the nonresponse criterion were retreated at clinician discretion. Crossover rates were 31% in the initial ibandronate group and 24% in the initial radiotherapy group.

Pain Response

There was no difference between ibandronate and radiotherapy in worst pain response at 4 weeks using WHO criteria (49.5% with ibandronate vs 53.1% with radiotherapy, difference = 3.7%, 90% confidence interval [CI] = −12.4% to 5.0%, P = .49) or 12 weeks (56.1% for ibandronate vs 49.4% with radiotherapy, difference = 6.7%, 90% CI = −2.6% to 16.0%, P = .24). Similar results were found at 26 and 52 weeks.

The response rate at 4 weeks was lower among patients who crossed over (33.8% for ibandronate then radiotherapy, 32.6% for radiotherapy then ibandronate) vs those who did not (58.1% for ibandronate alone, 59.8% for radiotherapy alone). Results were similar using EAS (differences of −7.5% and −3.5% at 4 and 12 weeks; the 90% confidence interval was almost within 15% at 4 weeks (−15.7% to 0.7%) and within 15% at 12 weeks (−12.3% to 5.3%). Similar outcomes were observed at 26 and 52 weeks.

Other Outcomes

Diarrhea (12% vs 6%) and nausea (26% vs 18%) were more common with radiotherapy, whereas other toxicities (19% vs 9%) were more common with ibandronate. There was no difference between treatments in quality of life assessed by FACIT-G at 4 weeks (P = .37) or 12 weeks (P = .84).

Median overall survival was 12.9 months with ibandronate vs 12.2 months with radiotherapy (P = .25), including 11.4 months with ibandronate alone, 11.8 months with radiotherapy alone, 16.8 months with ibandronate and then radiotherapy, and 12.7 months with radiotherapy and then ibandronate.

The investigators concluded: “A single infusion of ibandronate had outcomes similar to a single dose of radiotherapy for metastatic prostate bone pain. Ibandronate could be considered when radiotherapy is not available.”

Peter Hoskin, MD, of Mount Vernon Cancer Centre, Middlesex, is the corresponding author for the Journal of the National Cancer Institute article.

The study was funded by Cancer Research UK.

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