Study: Habitual Marijuana Smoking Not Associated With Increased Risk Of Lung Cancer

  • by Paul Armentano, NORML Deputy Director June 23, 2014

    Subjects who regularly inhale cannabis smoke possess no greater risk of contracting lung cancer than do those who consume it occasionally or not at all, according to data published online ahead of print in the International Journal of Cancer.

    An international team of investigators from Canada, New Zealand, the United Kingdom, and the United States analyzed data from six case-control studies involving over 5,000 subjects (2,159 cases and 2,985 controls) from around the world.

    Authors concluded, “Results from our pooled analyses provide little evidence for an increased risk of lung cancer among habitual or long-term cannabis smokers.”

    Investigators had previously presented their data at the 2013 annual meeting of the American Academy for Cancer Research.

    Their findings are similar to those of a 2013 review published in the journal Annals of the American Thoracic Society, which concluded: “[H]abitual use of marijuana alone does not appear to lead to significant abnormalities in lung function. … Overall, the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking.”

    An accompanying commentary in the same journal affirmed, “[C]annabis smoking does not seem to increase risk of chronic obstructive pulmonary disease (COPD) or airway cancers. In fact, there is even a suggestion that at low doses cannabis may be protective for both conditions.”

    Preclinical studies have documented that cannabinoids possess potent anti-cancer properties, including the inhibition of lung cancer cell growth. To date, however, scientists have yet to conduct controlled clinical trials replicating these results in human subjects.

    The abstract of the study, “Cannabis smoking and lung cancer risk: Pooled analysis in the International Lung Cancer Consortium,” appears online here.

    28 responses to “Study: Habitual Marijuana Smoking Not Associated With Increased Risk Of Lung Cancer”

    1. Patricia says:

      Marijuana prohibition is built on scientific fraud. The government discovered that THC killed lung cancer cells in 1974. That was 40 years ago! It is unconscionable that still there are no clinical trials in humans. The entire science community in America deserves to be censured for having turned a blind eye to this nonsense for 40 years.

      [Paul Armentano responds: Correct. The first preclinical models showing cannabinoids possess anti-cancer activity were conducted in 1974 and this data was published in 1975 in the Journal of the National Cancer Institute: http://www.ncbi.nlm.nih.gov/pubmed/1159836. Notably, CBD did NOT show anti-cancer activity in these models:

      “Lewis lung adenocarcinoma growth was retarded by the oral administration of delta9-tetrahydrocannabinol (delta9-THC), delta8-tetrahydrocannabinol (delta8-THC), and cannabinol (CBN), but not cannabidiol (CBD). Animals treated for 10 consecutive days with delta9-THC, beginning the day after tumor implantation, demonstrated a dose-dependent action of retarded tumor growth. Mice treated for 20 consecutive days with delta8-THC and CBN had reduced primary tumor size. CBD showed no inhibitory effect on tumor growth at 14, 21, or 28 days. Delta9-THC, delta8-THC, and CBN increased the mean survival time (36% at 100 mg/kg, 25% at 200 mg/kg, and 27% at 50 mg/kg, respectively), whereas CBD did not.”]

    2. Rocky Coast says:

      Re: Concentrates

      (Legal MMJ user here) A couple months ago I picked up a vaporizer pen that uses cartridges filled with concentrate. The “high” is not too much different overall, maybe more of a body high than the flower. When it comes to hybrids and indicas I really do prefer the vaporizer. With sativas I prefer the flower; the concentrate gives maybe too much of a body high for my tastes (although someone more athletically oriented might love it)

      I think the vape pens should be a positive contributor to our movement. Less combustible material going into your body!

      I see the point about edibles etc. having a possibly negative influence. This can be avoided by starting a sincere movement to get all “stoners” to act with class — no need to glorify it — just enjoy it and live your life.

    3. Galileo Galilei says:

      “The entire science community in America deserves to be censured for having turned a blind eye to this nonsense for 40 years.”

      To thwart the advance of medical science is a crime against us all.

    4. John says:

      Well this is fantastic news. I had no idea this much research has been done on pot. It’s a travesty that the substance which could help with cigarette addiction and alcohol abuse is the exact substance that the government considers to have no therapeutic use!

      The root of all evil is economics. Economics made pot illegal and through economics is the only way pot will be slowly legalized. Look at the laboratories of democracy in the US, Colorado and Washington, to see that it is the economic argument that has swayed voters. Nothing to do with research. The research is conclusive.

      America, smokers and non, let’s join hands to take the money away from criminal syndicates and build some fucking schools cuz I’m gonna smoke whether it’s legal and healthy or not.

    5. Ezry8 says:

      Someone needs to tell Gov Cuomo & Friends about this.
      Our bill in NY they made smoking it illegal, i think it is now a felony too Fuckin sad.

    6. Julian says:

      I heard patents last 20 years. Any hope patent “507” for cannabis as neuroprotectants owned by the Department of Health and Human Services could become open source within 7 years since it was unconstitutionally, immorally and hypocritically established in 2001?

    7. Raven says:

      And the scientific evidence just keeps pouring in. This is government imposed moral values. This is a violation of the first amandment.

    8. Adapt and counter the tactics says:

      While smoking should of course remain legal on private property, smoking cannabis will quickly become increasingly socially unacceptable. Vaporization of buds is low odor, clean and not a fire or security risk, even when traveling.
      Cannabis buds vaporized or low dose cooked should be promoted as the ideal form of cannabis consumption. This will counter the current tactic the pharmaceutical industry is using in attempt to takeover the cannabis industry. Americans have far more trust in cannabis buds than anything in pharmaceutical or concentrated form.
      Cannabis buds also provides the most support for the legalization of small secured private cannabis gardens. Small gardens avoid all the negative aspects associated with cultivation in residential areas. For a small garden, off the shelf small carbon filters remove all odor, and cool to the touch LED lighting eliminates all fire risk. These products plug into a standard outlet, there is no dangerous alteration to wiring or high voltages, small garden LEDs are very low wattage.
      Legitimate use of concentrates is mainly for serious medical conditions. It would make sense for Norml to propose that there should be minimal regulation of cannabis buds for adults, but concentrates are what need oversight.

    9. Ray says:

      @Paul – Cuomo needs to read this. I’ll send him a copy.

      Q: Has anyone heard how the Kentucky hemp crop is doing?

      Once all states realize the potential economic benefits and no risk reward for hemp farming we need to refrain from saying “I told you so” and say let’s strengthen our nation and grow more.

    10. Brian says:

      I think there needs to be some kind of organic pot shop campaigns or projects to make sure monsanto doesn’t take over and there should be some kind of symbol to let people know if certain shops are organic so we can continue to see more great studys like this one and keep monsanto out