Lyon, France: Smoking cannabis is not associated with an increased risk of developing cancers of the head and neck, according to the results of a case-control study published in the journal Cancer Epidemiology Biomarkers & Prevention.

An international team of investigators from France, the United States, Brazil, and Argentina assessed whether the "ever use" of marijuana was positively associated with head and neck cancers (HNC). Researchers pooled self-reported interview data on marijuana smoking and known HNC risk factors on 4,029 HNC cases and 5,015 controls. They reported that "infrequent marijuana smoking" was not associated with increased incidences of cancer.

"The risk of HNC was not elevated by ever marijuana smoking and there was no increasing risk associated with increasing frequency, duration, or cumulative consumption of marijuana smoking," investigators concluded.

Several previous studies have similarly failed to report a link between cannabis use and cancer. Last year, researchers in New Zealand reported in the journal Otolaryngology – Head and Neck Surgery that marijuana smoking, even long-term, was not associated with incidences of head or neck cancers.

In 2006, a UCLA study of more than 2,200 subjects (1,212 cases and 1,040 controls) reported that marijuana smoking was not positively associated with cancers of the lung or upper aerodigestive tract – even among individuals who reported smoking more than 22,000 joints during their lifetime.

Finally, a 1997 Kaiser Permanente retrospective cohort study of 65,171 men and women in California found that cannabis use was not associated with increased risks of developing tobacco-use related cancers – including lung cancer, breast cancer, prostate cancer, colorectal cancer, or melanoma.

Commenting on the latest study NORML Deputy Director Paul Armentano said: "The inhalation of cannabis smoke appears to present, at best, a nominal cancer risk – particularly when compared to tobacco smoke. This study is not newsworthy because its findings are anomalous; it is newsworthy because its findings are consistent with the existing literature in this field."

For more information, please contact Paul Armentano, NORML Deputy Director, at: paul@norml.org. Additional information on marijuana smoking and cancer risk is available in the online report, "Cannabis Smoke and Cancer: Assessing the Risk," at: Cannabis Smoke and Cancer: Assessing the Risk - NORML.

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