Opioid Use in Prostate Cancer Clinical Trials Appears to Vary by World Region

November 19, 2019

An international study of prostate cancer clinical trials discovered that opioid use appears to differ by region, implying that a variability should be considered.

A JAMA Oncology investigation found that opioid use appeared to vary by world regions in prostate cancer clinical trials, indicating that this variability should be considered in international clinical trials using delay in opioid initiation as an end point or otherwise incorporating opioid use into trial end points.1

This study documented the variability in opioid analgesic use across regions and countries, suggesting the existence of disparities in oncologic pain management in the previously unexplored controlled trial setting. If region is not a stratification factor, then sponsors may wish to assess regional variability when analyzing these end points, depending on their countries of recruitment.

In this international phase III randomized trial of 9,670 participants, patients in Eastern Europe (33%) and Asia (30.7%) were less likely to use opioids compared with patients in North America (59.1%), Oceania (54.1%), and Western Europe (56.1%). Across all regions, opioid use was more common in patients with high tumor burden and more advanced disease.

“Possible explanations for this disparity include local attitudes and practices as well as lack of access to opioids and potential undertreatment for patients in some cases,” the researchers wrote.

According to the American Cancer Society, sufficient access to opioid drugs for use in palliative care is often not available in resource-limited countries because of regulatory or pricing obstacles, lack of training and knowledge among health workers, and weak health care systems. The World Health Organization (WHO) has played an important role in encouraging effective pain management and monitoring the availability of opioids internationally.2

Variation in opioid use was seen across countries within a region as well. In Asia and Eastern Europe, a higher percentage of patients from high-income countries used opioids compared with those from not-high-income countries. However, variations were also seen across high-income countries within a region.

The Global Opioid Policy Initiative survey in Asia found that opioid consumption was highest in Korea, followed by Japan, and then China, a finding that was also reflected in this study. Similarly, this study’s finding of comparatively lower opioid use in Ukraine and Russia is consistent with results of previous research on country- and region-level opioid consumption.

“To our knowledge, no study has compared opioid use across patients with cancer from a range of different countries within the clinical trial setting,” the researchers wrote.

Opioids that were not classified using ATC codes were not captured, and the only excluded indications of opioid use were for pain prophylaxis associated with procedures.

Previous research on disparities in global opioid use has examined formulary availability and cost or evaluated data from the International Narcotics Control Board.

1. Roydhouse JK, Suzman DL, Menapace LA, et al. Global Variation in Opioid Use in Prostate Cancer Trials. JAMA Oncol. doi:10:1001/jamaoncol.2019.2971.
2. American Cancer Society. Global Cancer, Facts & Figures, 4th Edition. American Cancer Society website. cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/global-cancer-facts-and-figures/global-cancer-facts-and-figures-4th-edition.pdf. Published 2018. Accessed November 18, 2019.