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Link between cancer and pot is unclear

We have heard of many pros and cons about marijuana, including mind-altering, leading to other drugs, etc. However, I have not heard or read anything concerning cancer or dangers from secondhand marijuana smoke. Does this weed have the same effect as tobacco?


Even though we've never inhaled (or at least we can't remember if we did), we've wondered the same thing, G. So we went to the best source we could think of on this topic — the National Cancer Institute — to get an answer.

The answer we found on the institute's website is not totally clear-cut. Some studies have shown potential links between marijuana and cancer, while others have not. Here are a few of the studies cited by the institute:

  • An analysis of case studies on about 1,200 men in northwestern Africa showed a significantly increased risk of lung cancer among tobacco smokers who also inhaled marijuana.
  • A large study of 64,855 men age 15 to 49 from the United States found that marijuana use was not associated with tobacco-related cancers and a number of other common malignancies. However, the study did find that, among nonsmokers of tobacco, having used marijuana was associated with an increased risk of prostate cancer.
  • A study of 611 lung cancer patients revealed that "chronic low cannabis exposure" was not associated with an increased risk of lung cancer and found no connection with any cancer type — including oral, pharyngeal, laryngeal, lung and esophagus — when adjusting for other variables such as cigarette smoking.

Clearly, G, while there doesn't appear to be a strong link to cancer related solely to marijuana use, you're asking for trouble if you smoke cigarettes and pot. Then again, you're asking for trouble if you smoke only cigarettes.

There is a flip side to the health effects of marijuana: The institute also notes that marijuana is recommended by some physicians for cancer patients to help alleviate nausea and pain, stimulate appetite and improve sleep.

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