Researchers have found evidence that opioid use may be an unidentified risk factor contributing to the increasing incidence of pancreatic cancer in the United States. These findings were published by Barlass et al in PLOS One.

The use of prescription opioids for the management of chronic pain has increased remarkably, with more than 191 million opioid prescriptions given to patients in the United States in 2017. Addiction rates among patients who are given opioids for chronic pain have also increased, with 29% of such patients misusing opioids and 12% developing an opioid use disorder, according to a study published by Vowles et al in the journal Pain.

Pancreatic cancer rates also are increasing in the United States. Opioids have been shown to have a harmful effect on multiple types of cancer, with recent data suggesting opium use as a possible risk factor for pancreatic cancer in West Central Asia. Population-based studies—like one published by Moossavi et al in Cancer Epidemiology, Biomarkers & Prevention, and another published by Shakeri et al in Medicine—have suggested opium use may increase the risk of pancreatic cancer in a dose-dependent manner. While opium use is not a common recreational habit in the United States, the use of opioids has been rising remarkably over the past decade.

Study Methods

The new research team aimed to examine the possible association between the pattern of opioid use and the changes in the rates of pancreatic cancer from 1999 to 2016. Using the Centers for Disease Control’s WONDER online data (procured from the Vital Statistics Cooperative Program), the team extracted the opioid death rate as a surrogate for prescription and illicit opioid use. Incidence of pancreatic cancer was retrieved from the Centers for Disease Control and Prevention’s online database gathered from the U.S. Cancer Statistics Working Group. They extracted the pattern of the lifestyle and behavioral factors that over time could potentially affect the risk of pancreatic cancer.

Using national datasets, the team evaluated whether the trend in opioid usage could explain increasing pancreatic cancer diagnoses at the national and state levels over time after correcting for the potential confounding factors.

Findings

Researchers found that both pancreatic cancer and opioid death rates rose over time at the national and state levels. A prior state’s opioid death rate significantly predicted the trend in the incidence of pancreatic cancer years after and had a significant effect on the estimated annual change in the rate of this cancer.

The collected data suggests a possible link between opioid consumption and the risk of pancreatic cancer. The next step to directly establish the role of opioids as a novel risk factor for pancreatic cancer is to conduct large population-based studies or longitudinal datasets that reliably register long-term outcomes in opioid users. Findings from the current study—once confirmed by the individual-level data on opioid consumption and risk of pancreatic cancer—could have direct clinical relevance for considering nonnarcotic alternative pain control approaches in these patients. 

The team proposes to investigate possible mechanisms that may link opioid use to the development and/or progression of pancreatic cancer. Consistent with the current findings, a recent post hoc analysis of two randomized controlled trials of patients with advanced cancers (including pancreatic cancer) published by Janku et al in Annals of Oncology revealed that that those treated frequently with an opioid antagonist had significantly improved overall survival compared to placebo.

The study authors concluded, “In summary, our analysis of state-based databases suggests that opioid usage pattern may explain the trend of increased pancreatic cancer over time. Opioids as a novel risk factor pancreatic cancer needs to be confirmed in population-based studies.”.

Disclosure: For full disclosures of the study authors, visit journals.plos.org.