Randomized trial of low-dose morphine versus weak opioids in moderate cancer pain

Abstract

Purpose: The WHO guidelines on cancer pain management recommend a sequential three-step analgesic ladder. However, conclusive data are lacking as to whether moderate pain should be treated with either step II weak opioids or low-dose step III strong opioids. Patients and Methods: In a multicenter, 28-day, open-label randomized controlled study, adults with moderate cancer pain were assigned to receive either a weak opioid or low-dose morphine. The primary outcome was the number of responder patients, defined as patientswith a 20% reduction in pain intensity on the numerical rating scale. Results: A total of 240 patients with cancer (118 in the low-dose morphine and 122 in the weak-opioid group) were included in the study. The primary outcome occurred in 88.2% of the low-dose morphine and in 57.7% of the weak-opioid group (odds risk, 6.18; 95% CI, 3.12 to 12.24; P<001). The percentage of responder patients was higher in the low-dose morphine group, as early as at 1 week. Clinically meaningful (> 30%) and highly meaningful (> 50%) pain reduction from baseline was significantly higher in the low-dose morphine group (P