Shifting views on cancer pain management: a systematic review and network meta-analysis

CONTEXT: Strong opioids are the cornerstone in the treatment of cancer-related pain. OBJECTIVES: This study aims to compare analgesic effectiveness of different strong opioids for the treatment of cancer-related pain. METHODS: PubMed and Embase were searched for RCTs that compared strong opioids for treatment of cancer-related pain against one another. A network meta-analysis was conducted and the related Surface Under the Cumulative RAnking (SUCRA)-based treatment ranks were calculated. Primary outcome was pain intensity (numerical rating scale (NRS)) and/or the percentage of patients with =50% pain reduction, after 1 and 2-4 weeks. RESULTS: Sixteen RCTs (1813 patients) were included. Methadone showed, with a high certainty of evidence, increased ORs for treatment success at 1 week, compared with morphine, buprenorphine, fentanyl, and oxycodone, range 3.230-36.833. Methadone had the highest likelihood to be the treatment of preference (ToP) (SUCRA 0.9720). For fentanyl, ORs were lower, however significant and with high certainty. After 2-4 weeks, methadone again showed the highest likelihood for ToP, however, with moderate certainty and non-significant ORs. The combination of morphine/methadone, compared with morphine, buprenorphine, fentanyl, hydromorphone, methadone, and oxycodone achieved a treatment effect of mean NRS difference after 2-4 weeks between -1.100 and -1.528 and had the highest likelihood for ToP. CONCLUSION: The results suggest that methadone possibly deserves further promotion as first-line treatment for the treatment of cancer-related pain.