New study links cannabis use to reduced rates of prostate cancer

A new study using data from the National Survey on Drug Use and Health on men in the US has found a possible association between cannabis use and rates of prostate cancer. 

Researchers behind the study, published in the journal Biomedicines, observed that individuals who were former cannabis users had a significantly lower rate of self-reported prostate cancer. 

Prostate cancer is the second most common form of cancer and the fifth leading cause of cancer-associated death in males worldwide, with an estimated 1.4 million new cases and 375,000 deaths worldwide per year. 

While preclinical studies have demonstrated “anti-tumour effects” of cannabinoids in prostate cancer, the potential reduced risk related to regular use of cannabis is an area which remains “understudied”, according to the authors. 

The research team conducted a cross-sectional study using National Survey on Drug Use and Health data collected from over 2,500 participants between 2002 to 2020.

Most participants were 65 and older and 36% reported having a diagnosis of prostate cancer at the time of interview.

In the full sample, just over half (53.4%) reported never having used cannabis, 40.8% identified as former users, and 5.8% said they were current consumers. 

The researchers found a combined 21% reduction in prostate cancer among cannabis users compared to that among non-users. More specifically, there was a 22% reduction among cannabis users aged 65 years, compared to their counterpart non-users—an effect that was not significantly observed in the younger age group (50–64 years). 

Analyses of the findings suggested that former cannabis users reported a “significantly lower prevalence of PC compared to non-users”. While self-reported rates of prostate cancer among current users also trended towards a lower prevalence this was not statistically significant, the authors say. 

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“Our findings provide corroborative data from a large national, population-based survey to strengthen the existing body of evidence suggesting a potentially protective role of marijuana against the development of PC,” they state, in the paper’s discussion section.

“Since medical marijuana is being used more frequently in cancer patients for pain control, nausea, and abdominal pain and nearly half of oncologists report prescribing medical marijuana to patients at some point in their practice, future prospective studies in patients on medical marijuana may facilitate our further understanding of potential anticancer properties.”

While the study has some limitations, including the fact that data was largely collected from non-Hispanic white participants with little representation of other ethnicities.

However, the authors believe it to be the first investigating the association between cannabis use and prostate cancer in a large cohort, using “a national survey focused on the at-risk group of the older male population”.