The role of methadone in cancer-induced bone pain: a retrospective cohort study.

Purpose: Cancer-induced bone pain (CIBP) can be challenging to manage in advanced cancer. The unique properties of methadone may have a role in refractory CIBP. We aimed to evaluate the analgesic effects of methadone for CIBP when other opioids are ineffective or intolerable.

Methods: A retrospective study of palliative care inpatients rotated to methadone from another opioid for CIBP over a 4-year period. Primary outcome was ≥ 30% reduction in pain intensity (11-point numeric rating scale) from baseline to completion of methadone rotation (MR). Secondary outcomes were ≥ 50% reduction in pain intensity and changes in long-acting and breakthrough opioid requirements.

Results: Ninety-four eligible patients completed MR for the following reasons: poor pain control (72.3%), opioid toxicities (4.3%) or both (23.4%). On completion of MR, 70.2% and 53.2% achieved a ≥ 30% and ≥ 50% reduction in pain respectively, with mean pain intensity score reduced from 5.6 (SD = 2.1) at baseline to 2.6 (SD = 2.5) (p < 0.001). Mean calculated daily methadone dose pre-MR was 25.7 mg (SD = 10.9), with 72.3% of patients requiring a lower dose on completion of MR (mean 17.0 mg, SD = 8.5). The mean number of breakthrough opioid analgesia used a day reduced from 3.4 (SD = 2.3) to 1.8 (SD = 1.7) (p < 0.001).

Conclusions: MR for CIBP may result in reduction in pain intensity, when other opioids are ineffective or intolerable, with patients requiring reduced overall dosing of their long-acting opioid and frequency of breakthrough opioid use.