A high proportion of patients with cancer are among a growing number of Americans who used marijuana over the past several years, likely reflecting greater availability of cannabis as a result of widening legalization, according to study results published in Cancer.
The study also found that patients with cancer are more likely to use prescription opioids than adults without cancer, although odds of opioid use among both populations did not change significantly between 2005 and 2014.
“Medical marijuana legalization has previously been associated with a reduction in hospitalizations related to opioid dependence or abuse, suggesting that if patients are, in fact, substituting marijuana for opioids, this may introduce an opportunity for reducing opioid-related morbidity and mortality,” Jona Hattangadi-Gluth, MD, chief of the central nervous system tumor and liver tumor services at UC San Diego Health, said in a press release. “Of course, it will also be important to identify risks and adverse effects of marijuana, which has not previously been studied in large randomized clinical trials, given it’s scheduling as a class 1 controlled substance.”
Recent studies have suggested that marijuana may be an alternative to prescription opioids in some instances for managing cancer-related pain.
Hattangadi-Gluth and colleagues used data from the U.S. National Health and Nutrition Examination Survey to study trends in self-reported marijuana and prescription opioid use between 2005 and 2014 among patients with cancer compared with controls without cancer.
The 19,604 survey respondents aged 20 to 60 years included 826 patients with cancer (mean age, 47.4 years; 66.7% women), who researchers propensity score-matched with 1,652 noncancer controls (mean age, 46.7 years; 66% women).
Results showed that compared with controls, a greater proportion of patients with cancer reported use of marijuana within the past year (40.3% vs. 38%) and current marijuana use (8.7% vs. 6.6%).
Multivariable conditional logistic regression analyses found no association between cancer and current marijuana use. However, results showed a significant association between cancer and current opioid use (OR = 1.82; 95% CI, 1.17-2.82).
Patients with cancer appeared significantly more likely to use prescribed opioids than respondents without cancer (13.9% vs. 6.4%; OR = 2.43; 95% CI, 1.68-3.57) and were significantly more likely to smoke cigarettes (52.9% vs. 47.2%; OR = 1.34; 95% CI, 1.09-1.65).
The number of patients with cancer who reported using marijuana increased 118% between 2005 and 2014, compared with a 12.5% increase among respondents without cancer during that period.
Meanwhile, opioid prescription use increased among patients with cancer (from 9.6% to 14.4%) and respondents without cancer (from 5% to 7.8%).
Researchers noted that the findings of the cross-sectional study were not indicative of a causal relationship between cancer and marijuana or opioid use, and that use of opioids was calculated based on prescriptions and did not account for any potential abuse.
“These data provide the first insight into marijuana and opioid use over time in people with cancer across the United States,” Hattangadi-Gluth and colleagues wrote. “Prospective clinical trials are needed to quantify the efficacy of marijuana in cancer-specific pain as well as the risk [for] opioid misuse in this patient population.” – by John DeRosier
Disclosures: The NIH funded this study. Hattangadi-Gluth reports research funding from Varian Medical Systems. No other authors report relevant financial disclosures.