Could two rights make a wrong? Cannabis and immunotherapy have both gained traction in the oncology field in recent years — one to help treat symptoms and the other as a gentler alternative to chemotherapy — but there’s been some concern that for cancer patients using both, the former could interfere with the latter.1,2 A newly published study in the European Journal of Cancer,3 however, suggests there may be nothing to fear.
Drugs called immune checkpoint inhibitors are a form of immunotherapy that have transformed — with better targeting and less severe side effects — the treatment of many cancers, including non-small cell lung cancer (NSCLC). Immune checkpoint inhibitors are routinely administered as first-line treatments for NSCLC, either alone or in combination with chemotherapy.
Cannabis, too, has become more widely used among cancer patients over the past decade, paralleling its growing societal acceptance and expanding medical use. In addition to preclinical research and anecdotal accounts indicating that cannabinoids may have anti-cancer effects, cannabis is also well known to mitigate many symptoms and side effects of cancer and cancer treatment, including nausea, pain, and suppressed appetite.
Red Flags from Earlier Studies
Worries about the potential incompatibility of these two treatments stem from the fact that the cannabinoid receptor CB2 is predominately expressed by immune cells, and its activation may suppress immune function. Immunotheraperies like immune checkpoint inhibitors depend upon a robust response to do their work. It’s at least plausible, then, that cannabis might interfere with immunotherapy: instead of helping, it may actually hurt.
In fact, that’s exactly what two previous studies from an Israeli research team in 20194 and 20205 have suggested — though, as the authors of the new paper, also based in Israel, argue right off the bat, those earlier findings come with some pretty large caveats. “These studies included patients with various cancers, treatment regimens, and lines of therapy and were given [immune checkpoint inhibitors] at advanced line shortly before death,” the authors write. “Under these circumstances, the use of cannabis is often a mere surrogate for high-burden symptomatic disease.”









