Frequency, Rationale, and Doses for Opioid Switching in Advanced Cancer: A Longitudinal Cohort Study.

Abstract

Background: Pain is common in advanced cancer, and many people require opioid switching to achieve adequate analgesia. However, longitudinal patterns of switching across the complete illness trajectory remain poorly characterized. This study describes the incidence, indications, dose thresholds, and prescribing patterns of opioid switching from advanced cancer diagnosis to death.

Measures: This retrospective cohort study analyzed opioid prescribing data for 200 adults with advanced cancer from diagnosis to death. Prescribing data were converted to standardized oral morphine equivalent daily dose (oMEDD). Switching frequency, dose thresholds, duration of opioid use, documented indications, and prescriber patterns were analyzed using descriptive statistics.

Outcomes: Opioid switching occurred in 58% of patients (n = 116), with some requiring up to four switches. Each successive switch occurred after substantial dose escalation during treatment on a given opioid, where starting doses of each successive switch approximately doubled: 20 mg oMEDD for the first opioid, 30 mg at first switch, 60 mg at second, and 180 mg at third switch. Median duration on each opioid progressively shortened with each switch: 39 days interquartile range (IQR 9-98), 25 days (IQR 6-103), and 18 days (IQR 5-53) for the first, second, and third switches, respectively. Inadequate analgesia was the predominant indication (58% of switches). Palliative care clinicians initiated an increasing proportion of switches (31% of first opioids; 89% of third).

Conclusion/lessions learned: Opioid switching is common across the advanced cancer trajectory, characterized by progressive dose escalation and shortening duration of use with each successive switch. These findings highlight the importance of access to multiple opioid options and timely specialist palliative care involvement.