Marijuana and Lung Cancer: Cause Or Cure?


  • Evidence of marijuana’s cancer-fighting ability dates back to the 1970s
  • Lung cancer is the leading cause of cancer deaths in the US and is highly resistant to chemotherapy
  • Studies have failed to confirm a link between marijuana use and lung cancer
  • Recent studies show that THC and CBD are able to reduce the growth and spread of lung cancer
  • THC and CBD are also useful in reducing the side-effects of chemotherapy
  • Clinical trials have yet to be conducted on medical marijuana and cancer – Most people think of marijuana as being a risk factor for lung cancer and would probably have a hard time imagining it as a treatment. However, while the smoke from marijuana and tobacco share a number of similar carcinogenic chemicals, decades of research have failed to confirm a link between marijuana use and lung cancer.

On the other hand, research has shown that marijuana has a unique ability to fight cancer, even when it affects the lungs.

What is Lung Cancer?

Picture of small cell lung cancer

Lung cancer is an often fatal disease and remains the leading cause of cancer-related deaths in the United States.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 85% of all cases. Unfortunately, the prognosis for patients with NSCLC is poor and fewer than 15% survive beyond 5 years of their diagnosis.

As of today, there are a limited number of medical treatments available for NSCLC patients – chemotherapy and surgery being the most common. However, metastatic cancer makes surgery a non-option and advancements in chemotherapy have been minor over the last 20 years. Worse is that all patients will eventually develop a resistance to chemotherapy drugs, making it necessary for researchers to explore other options.

How Can Marijuana Help?

Evidence of marijuana’s cancer-fighting properties dates as far back as the 1970s. Munson et al. (1975) were the first group of researchers to find that orally administered THC could slow tumor growth and increase survival rates in animal models of lung cancer. However, research on medical marijuana and lung cancer grew sparse in the following years and has only recently picked up again.

In 2008, researchers at Harvard University’s Division of Experimental Medicine published the first study in many years to investigate the effects of THC on lung cancer. Using animal models and cell cultures, the researchers found that THC treatment over a 28 day period resulted in a 50% reduction in tumor growth and a 60% reduction in cancerous lesions.

Looking to further investigate these results, the team of Harvard researchers published another study in 2011 – using synthetic cannabinoids instead of THC – and observed a similar effect. By only targeting cannabinoid receptors, the researchers were able to reduce both the tumor growth and spreading of cancer by 50%. The study was also the first to show that cannabinoid receptors are overexpressed in lung cancer cells, which further supports the therapeutic potential of medical marijuana and cannabinoids in lung cancer.

More recent studies have found CBD – another cannabinoid found in marijuana – to have a similar effect on lung cancer. While CBD and THC both exhibit incredible medical properties, health professionals prefer the use of CBD due to its lack of psychoactive effects. CBD has also been found to mitigate the unwanted side-effects of toxicity, inflammation and cell death that are associated with chemotherapy.

Medical Marijuana and Cancer

One of the most important findings of medical marijuana research thus far has been the versatility of marijuana’s cancer-fighting properties. Indeed, cannabinoids have been suggested as an effective treatment for not only lung cancer, but also cancers of the liver, breast, and prostate, to name just a few. In addition to reducing the growth and migration of cancer cells, cannabinoids have also been found to inhibit the blood supply of tumors (angiogenesis) and modulate the immune response.

While the use of marijuana-based treatments for cancer has yet to be tested in clinical trials, a number of synthetic cannabinoid drugs are available today for the treatment of cancer-related pain and nausea. For example, synthetic THC (Marinol) can be prescribed in both Canada and the United States for patients who suffer from nausea and vomiting associated with chemotherapy.

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