Methadone versus other opioids for refractory malignant bone pain: a pilot randomised controlled study.

PURPOSE: Refractory cancer-induced bone pain (CIBP) affects a patient's functional capacity and quality of life, but there is limited evidence to guide opioid choice. We assessed the feasibility, tolerability and possible efficacy of methadone rotation (MR) compared to other opioid rotations (OOR) in this cohort. METHODS: Adults with CIBP and worst pain intensity ≥ 4/10 and/or opioid toxicity graded ≥ 2 on the Common Terminology Criteria for Adverse Events were randomised 1:1 to methadone or another opioid rotation. Standardised assessment tools were used at pre-defined study time points up to 14 days. RESULTS: Of 51 eligible participants, 38 (74.5%) consented, and 29 (76.3%, MR: 14, OOR: 15) completed the fourteen days follow-up post-opioid rotation. Both groups displayed significant reduction in average (MR: d = - 1.2, p = 0.003, OOR: d = - 0.8, p = 0.015) and worst pain (MR: d = - 0.9, p = 0.042, OOR: d = - 0.6, p = 0.048) and total pain interference score (MR: d = - 1.1, p = 0.042, OOR: d = - 0.7, p = 0.007). Oral morphine equivalent daily dose was reduced significantly in MR compared to the OOR group (d = - 0.8, p = 0.05). The incidence of opioid-related adverse events following MR was unchanged but lower in the OOR group (d = 0.9, 95% CI 0.1,1.7, p = 0.022). There were no within-group or between-group differences in satisfaction with analgesia at the end of the study. CONCLUSION: This pilot study demonstrated that MR and OOR in patients with refractory CIBP are feasible, safe and acceptable to patients. Appropriately powered multi-centre randomised controlled studies are needed to confirm the efficacy of MR and OOR in this cohort. TRIAL REGISTRATION: ACTRN12621000141842 registered 11 February 2021.

The Edmonton Classification System for Cancer Pain in Patients with Bone Metastasis: a descriptive cohort study.

PURPOSE: We describe the prevalence of the Edmonton Classification System for Cancer Pain (ECS-CP) features in patients with bone metastasis and cancer-induced bone pain (CIBP) and the relationship between ECS-CP features, pain intensity, and opioid consumption. METHODS: We assessed ECS-CP features and recoded pain mechanisms and opioid use in adult patients with bone metastasis. Validated measures were used to assess pain intensity, incident pain, psychological distress, addictive behavior, and cognition. RESULTS: Among 147 eligible patients, 95.2% completed the assessment. Mean participant age was 73.2 years, the majority female (52.1%) with breast cancer occurring most commonly (25.7%). One or more ECS-CP features were present in 96.4% and CIBP in 75.7% of patients. The median average and worst pain scores were 3 and 6, respectively. Neuropathic pain was the most prevalent pain mechanism (45.0%) and was associated with breakthrough pain frequency (p=0.014). Three-quarters had incident pain, which was strongly associated with a higher average and worst pain scores (3.5 and 7, p<0.001 for both), background oral morphine equivalent daily dose (26.7mg, p=0.005), and frequency of daily breakthrough analgesia (1.7 doses/day, p=0.007). Psychological distress (n=90, 64.3%) was associated with a significantly higher average pain score (4, p=0.009) and a slightly higher worst pain score (7, p=0.054). Addictive behaviour and cognitive dysfunction were relatively uncommon (18.6% and 12.9%, respectively). CONCLUSION: There is a need to promote standardized assessment and classification of pain syndromes such as CIBP. The ECS-CP may allow us to consider CIBP in a systematic manner and develop personalized pain interventions appropriate to the pain profile. TRIAL REGISTRATION: Retrospectively registered in ANZCTR ACTRN12622000853741 (16/06/2022).