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Does Smoking Marijuana Cause Lung Cancer?

Smoking Marijuana Lung Cancer

Multiple studies have confirmed marijuana’s ability to treat cancer symptoms, including chemotherapy side effects. More recent research has even suggested that marijuana may play a role in slowing and/or stopping cancer cells from dividing and, in some cases, even triggering cancer cell death.

But what about smoking marijuana? Is there any risk that inhaling cannabis could actually cause cancer?

Today, CannaMD takes a closer look at what the most current peer-reviewed research has to say.

How Does Marijuana Help Cancer?

The term cancer refers to a group of related diseases. In each case, some of the body’s cells begin dividing and spread into surrounding tissue.

Normally, cells grow and divide as we need them. When cells become old or damaged, they die and new cells take their place. However, when cancer develops, this system falls apart: Old and damaged cells survive when they shouldn’t and new cells form when they aren’t needed.

That’s why scientists with the Journal of Molecular Medicine were so excited to discover that marijuana may slow and/or stop cancer cells from dividing. Adding more fuel to the fire, a study published by Molecular Cancer Therapeutics concluded that marijuana cannabinoid, CBD, “induced programmed cell death in breast cancer cells.”

As summarized by the National Cancer Institute:

Cannabinoids appear to kill tumor cells but do not affect their non-transformed counterparts and may even protect them from cell death.

Of particular interest to today’s post, a recent study of an 81-year-old man with lung cancer supports the idea that CBD may help reverse tumor growth.

The patient, who had chosen not to receive chemotherapy or other cancer treatments because he was concerned they would decrease his quality of life, decided to use CBD oil twice a day. Within two months, the tumor in his lung underwent a “significant reduction in size” to what doctors described as a “near total resolution.”

(For more details, see: Lung Cancer Tumor Shrinks After CBD Use.)

While these studies mark an exciting step in cancer research, a lot of work remains to be done.

Until then, marijuana continues to be used more commonly to treat cancer-related painloss of appetite, and anxiety.

For a deeper dive on cannabis and cancer, consider reading: Everything We Know About Marijuana & Cancer.

Does Smoking Marijuana Cause Lung Cancer?

While research is limited, the National Cancer Institute has catalogued the most significant studies to date. Results are outlined below.

In 1997, a retrospective cohort study of 64,855 participants (aged 15-49) found that:

Marijuana use was not associated with tobacco-related cancers or with cancer of the following sites: colorectal, lung, melanoma, breast.

Likewise, a population-based case-control study of 611 lung cancer patients revealed that chronic low cannabis exposure was not associated with an increased risk of lung cancer or other upper aerodigestive tract cancers. Furthermore, the study found no positive associations with any cancer type (oral, pharyngeal, laryngeal, lung, or esophagus) when adjusting for several confounders, including cigarette smoking.

These results led researchers to conclude:

[This study] suggests that the association of these cancers with marijuana, even long-term or heavy use, is not strong and may be below practically detectable limits.

As summarized by the National Cancer Institute, a systematic review assessing 19 studies that evaluated premalignant or malignant lung lesions in persons 18 years or older who inhaled marijuana concluded that:

Observational studies failed to demonstrate statistically significant associations between cannabis inhalation and lung cancer after adjusting for tobacco use.

In a review of the published meta-analyses, the National Academies of Sciences, Engineering, and Medicine concluded:

There was moderate evidence of no statistical association between cannabis smoking and the incidence of lung cancer.

Supporting this conclusion, Canadian reports note:

At present, no conclusive positive associations can be drawn between cannabis smoking and incidence of lung or upper airway cancer.

Lastly, in what has been called “the largest and longest study ever” to consider the issue of marijuana and impaired lung function, the Journal of the American Medical Association found that:

Occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function.

Interestingly, results also suggest that low and moderate levels of marijuana use may even improve lung function, as measured by two lung capacity tests: FEV1 and FVC.

As associate professor of epidemiology and biostatistics at the University of California and lead study author Dr. Mark Pletcher explains:

FEV1 and FVC both actually increased with moderate and occasional use of marijuana […] It’s a weird effect to see and we couldn’t make it go away.

What About Other Cancer Risks?

While research is still young, scientists are optimistic about low risk associations between cannabis and other types of cancer, respiratory, and pulmonary diseases.

According to Canadian reports:

The association between chronic heavy cannabis smoking (without tobacco) and chronic obstructive pulmonary disease, is unclear, but if there is one, is possibly small.

Addressing another potential risk of smoking marijuana, the National Cancer Institute states:

Epidemiologic studies examining association of cannabis use with head and neck squamous cell carcinomas have been inconsistent in their findings.

A systematic review and meta-analysis of nine case-control studies involving 13,931 participants, supports this conclusion, noting that there was “insufficient evidence” to support or refute a positive or negative association between marijuana smoking and the incidence of head and neck cancers.

However, it should be mentioned that the retrospective cohort study discussed earlier, that found that marijuana use was not associated with tobacco-related cancers or lung cancer, did find that among nonsmokers of tobacco “ever having used cannabis” was associated with an increased risk of prostate and cervical cancer.

Researchers concluded that:

In this relatively young study cohort, marijuana use and cancer were not associated in overall analyses, but associations in nonsmokers of tobacco cigarettes suggested that marijuana use might affect certain site-specific cancer risks.

Where Can I Learn More?

Interested in learning more about medical marijuana? Download our free e-book today!

CannaMD‘s team of certified medical marijuana doctors are also on hand to answer any questions you may have. Give us a call at 1 (855) 420-9170 and let us know how we can help!

You can also find out if you qualify for medical marijuana treatment by filling out a quick online application!

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  1. I was told & have no proof of evidence other than rumor that anyone approved for a Medical Marijuana Card could not possess a firearm in the state of Florida and that those holding a Concealed Weapons Permit would have to surrender their permit. Nor would anyone applying for a Concealed Weapons Permit be approved should they have Medical Marijuana Card. So what is the truth?

    1. Hi Willard! That’s definitely a tricky subject, we recommend checking out Commissioner of Agriculture Nikki Fried’s comments here!

  2. I have qualified and paid to buy the vapor product .It did nothing for me .
    Was I getting the wrong stuff.
    My card will be expiring .Does this mean a new charge before I can purchase different products ,that might help my pain and Glaucoma?

    1. Hi Lorraine! Are you a current CannaMD patient? If so, we’d be happy to adjust your orders free of charge! Please feel free to give us a call at 1 (855) 420-9170 or email your physician directly 🙂

  3. I have been told for years that smoking weed causes lung cancer, fried brains, and all sorts of bad stuff. I have found none of it to be true. I’ve used it on and off since 1972. The only problem I’ve had is other people!

  4. I’ve been smoking flower for years but switched to vaping about three years ago. I continued to vape daily using THC Sativa, Hybrids & Indica’s and this past February I got a bad case of bronchitis that took about a month to clear up and then in March I got a terrible case of pneumonia that once again took about a month to dissipate. I was left with a Mucous Plug in one lung that is slowly dissolving. My pulmonologist at Mt. Sinai in Miami, was positive the vaping caused all the trouble recommending to never vape again. I was not his only patient that came to him with these problems. I bought all the vaping paraphernalia from legitimate dispensaries including Trulieve, Surterra, Rise, Fluent & Curaleaf. This must be addressed by CannaMD as well as other reputable publications and sources.
    I feel lucky that I didn’t get sicker than I did and have switched to oils, tinctures and edibles, which are not causing any problems.
    I do wonder however, if flower is ok while vaping is not.
    Let’s not drop the ball on this and please do follow-ups on these serious, life threatening problems.
    Reach me if you’d like to discuss further.
    Thank you.

  5. hi. i vaped thc oil hard for a few yrs and now 4 rys later i have throat cancer. at 40 yrs old. i factually know vaping [c-cell cannabis oil cartridges] caused my first sign of it 3 yrs ago. i stick to smoking flower and vaping flower out of a volcano and it SEEMS to help . i do not get high no matter what. i even ate over 25,00mg of high quality 87% r.s.o. and everyone else got blasted off a rice sized drop. i dont mind, but dont get why i CANT get a psycoactive expierience at all from the most potent thc combos and veriations. id love Anyones opinion. im mentally retarted but phyisically i box well and all that, i need info. i do have trauma from head kicks while being jum,ped 1 time. also acid “od” at 14 yrs old. and other trauma. GOD bless yall!! mike p

    1. What! That’s crazy!!! Cancer! I’m so sorry to hear that!! I am worried that I’m getting COPD from smoking oil and I’m having a hard time quitting!! 😩

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