Randomized Trial Finds Low-Dose Morphine Superior To Weak Opioids for Moderate Cancer Pain
In cancer patients who were experiencing moderate pain, low-dose morphine reduced pain intensity significantly compared with weak opioids, with similarly good tolerability and an earlier effect, according to a multicenter trial based in Italy and including a researcher from the MD Anderson Cancer Center in Houston, Texas.
The purpose of the comparative study was to address the World Health Organization (WHO) guidelines on cancer pain management. The guidelines currently recommend a sequential 3-step analgesic ladder. However, the researchers noted, conclusive data did not exist as to whether moderate pain should be treated with either step II weak opioids or low-dose step III strong opioids.
In the multicenter, 28-day, open-label randomized controlled study, a total of 240 adults with moderate cancer pain were assigned to receive either a weak opioid (n = 118) or low-dose morphine (n = 122). The primary outcome was the number of responder patients, defined as patients with a 20% reduction in pain intensity on the numerical rating scale.
Of the low-dose morphine group, 88.2% of the patients reported a reduction in pain intensity of at least 20%. Only 57.7% of the patients who received a weak opioid reported similar pain reduction (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 (>=0%) reduction of pain from baseline was significantly higher in the low-dose morphine group.
A change in the assigned treatment occurred more frequently in the weak-opioid group, because of inadequate analgesia.
Just as importantly, the general condition of patients, which was based on the Edmonton Symptom Assessment System overall symptom score, was better in the morphine group.
Adverse effects were similar in both groups, the authors reported, concluding that overall, for cancer patients with at least moderate pain, low-dose morphine led to significantly better outcomes. (See Bandieri E, Romero M, Ripamonti C, et al. Randomized trial of low-dose morphine versus weak opioids in moderate cancer pain. J Clin Oncol. 2015 Dec 7. pii: JCO610733; Epub ahead of print. http://jco.ascopubs.org/content/early/2016/01/07/JCO.2015.61.0733.long.)