Cannabis use is associated with a reduced risk of oral cancer, according to the results of a systematic review and meta-analysis published in the Journal of Ethnicity in Substance Abuse.
An international team of investigators from Jordan, Iraq, and Uzbekistan reviewed data from six case-control studies involving over 15,000 subjects.
Researchers identified no dose-response relationship between cannabis use and a heightened risk of oral cancers, regardless of subjects’ duration of use. Instead, investigators suggested that cannabis may provide “significant protective effects” against cancer. They caution, however, that their findings may be influenced by confounders, particularly researchers’ failure to identify subjects’ HPV (human papillomavirus) status. (HPV infection is linked to elevated cancer risk.)
“The pooled odds ratio demonstrated a statistically significant inverse association between marijuana use and oral cancer risk (OR = 0.66),” the study’s authors concluded. “However, given methodological limitations, heterogeneity in exposure assessment, and conflicting recent evidence, these findings require cautious interpretation. Future large-scale prospective cohort studies with standardized exposure measurements are essential for definitive conclusions.”
While cannabinoids have demonstrated well-established anti-cancer activities in preclinical models, their efficacy as an anti-cancer agent has rarely been assessed in clinical trials.
Full text of the study, “The association between marijuana use and oral cancer risk: A systematic review and meta-analysis of case-control studies,” appears in the Journal of Ethnicity in Substance Abuse.
