In a recent issue of the medical journal CHEST, Dr. Pauline Pradère et al examined health records of 150 French patients with lung cancer and observed very high rates of patients who smoke – not only tobacco (91%), but many who smoke both cannabis and tobacco (39%).
In that same issue of CHEST, UW-CTRI Director Dr. Hasmeena Kathuria and Researcher Dr. Jesse Kaye analyzed the results, raising concerns about the health effects of co-use uncovered by Pradère et al, including increased rates of thoracic pain, emphysema, more aggressive lung cancer and longer surgical times.
“Their findings from France highlight important areas for future research,” Kaye said. “It is certainly plausible that co-use may increase lung cancer risk because of additive exposure to carcinogens. Research is needed to examine patients who smoke cannabis only, but who do not smoke tobacco, to draw stronger conclusions about the negative health effects of smoking cannabis.”
Years ago, UW-CTRI Founding Director Dr. Michael Fiore and Research Director Dr. Timothy Baker coined the idea that quitting cigarettes was the “fourth pillar” of cancer care, along with surgery, radiation, and chemo/immunotherapy.
A year after their cancer diagnosis, Pradère et al found that patients who co-used were nearly twice as liking to still be using than those who smoked only cigarettes.
“Research shows that cannabis co‑use is associated with lower odds of successfully quitting cigarettes, which is a significant concern,” Kathuria said. “There is a clear need for more research to identify effective, tailored approaches to help people quit, including those who use nicotine alongside cannabis in its many forms.”
“Likewise, because patients with cancer are increasingly using cannabis through government-regulated medical programs, it is important to understand how to balance the potential therapeutic benefits with potential harms,” Kaye said.
The authors pointed out that, as cannabis laws evolve on the local, state and federal levels, so too will research need to try to keep up.
Kaye JT, Kathuria H. (2026) Rethinking Smoking Cannabis, Tobacco, and Lung Cancer. Chest. 169; 3: 586-588. Online March 1, 2026. Research was supported by the National Institute on Drug Abuse of the National Institutes of Health under Award Number K23DA063870 (J. T. K.).