Cannabis and cancer

Every year, nearly 2 million people in the United States are diagnosed with some form of cancer. As challenging to treat as it is common to diagnose, cancer can occur anywhere in the body but most often affects the breasts, lungs, and colon. 

Medical cannabis has emerged as an alternative treatment option for a number of ailments including Parkinson's disease and diabetes. Can marijuana help treat a disease as complex as cancer? In this article, we'll examine the current research on cannabis for cancer and hear what the experts have to say. 

An overview of the research

The cannabinoids and other compounds found in cannabis have shown to be potentially beneficial in the treatment of cancerous tumors. Both in vitro (petri dish) and in vivo (animal) studies have demonstrated how medicinal cannabis, including whole-plant extract and hemp, may be useful tools in the battle against cancer. 

Studies on cannabis and cancer

One comprehensive 2020 study published in the scientific journal Cancers analyzed the anti-cancer efficacy of different chemical compounds present in cannabis. These included prominent cannabinoids such as THC and CBD, as well as the lesser-known CBG and CBN, in addition to potent flavonoids and terpenes. The researchers concluded that, while cannabis would not likely succeed as a stand-alone therapy, “...many of the compounds present in cannabis could be part of a therapeutic solution for patients living with and beyond cancer.”

cannabis and cancer
While cannabis would not likely succeed as a stand-alone therapy, it could be part of a therapeutic solution for patients living with cancer.
Photo by: Gina Coleman/Weedmaps

Here are some highlights of the study's findings:

  • Linalool, a common terpene in cannabis, was found to reduce the viability of oral cancer cells
  • Limonene, another abundant terpene in cannabis, exhibited anti-cancer effects by reducing tumor enlargement and suppressing the growth of bladder and colon cancer cells
  • CBD, a non-intoxicating cannabinoid derived from hemp, inhibited the metastasis of lung cancer cells 
  • THC, a psychoactive cannabinoid, decreased the viability of pancreatic cancer cells
  • Dronabinol, a synthetic marijuana-based drug, aided in reducing nausea in patients undergoing chemotherapy while also reducing the viability of leukemia cells

Additional 2020 research published in the International Journal of Molecular Sciences examined the potential role of cannabinoids in combating melanoma (skin cancer). Researchers considered the results of six in vivo studies before determining that “...cannabinoids, individually or combined, reduced tumor growth” in addition to inducing the death of melanoma cells.

Medical cannabis patients share their stories

Singer Olivia Newton-John was diagnosed with breast cancer in 2013 and has tried several therapies to manage the associated pain. Cannabis medicine is one treatment supplement that has worked well for Newton-John, now 72. She told MedPage Today in 2019, “I really believe cannabis has made a huge difference. If I don't take the drops, I can feel the pain, so I know it's working.”

The pain that Newton-John is referring to stems not only from breast cancer but also from a tumor in her sacrum which left her wheelchair-bound and dependent on morphine. Along with marijuana, Newton-John relies on herbs, hormone suppression therapy, and meditation to manage her pain. She cites her use of cannabis oil as a primary factor in weaning off morphine.

At just 23 years old, Cheyann Shaw was diagnosed with stage 4 ovarian cancer. The Florida native has shared her story on social media and on Healthline in a 2019 article titled, “I Tried Medical Cannabis During Chemo, and Here's What Happened.” Shaw wrote, “The world often felt like too much, and my anxiety would kick in. But when I took my THC and CBD pills, both the exhaustion (thanks to sleep) and the anxiety would go away.” Now 26 years old, Shaw is still battling cancer after a period of remission. 

It should go without saying that any cancer patient who wishes to use medical cannabis as a supplemental treatment should consult with a qualified physician first. 

What the experts say about cannabis and cancer

Dr. Adie Rae, a neuroscientist and scientific adviser to Weedmaps, reiterated the importance of cancer patients consulting with their physicians. “Clinical studies are complicated. Although cannabis-using cancer patients typically have better outcomes (overall survival and tumors take longer to develop), cannabis has major interactions with the immune system. Most traditional cancer therapies are immuno-modulators. If a patient is on immunomodulatory medications, cannabis could interfere with their effectiveness. So, it's very important to discuss cannabis use with the oncologist.”

cannabis and medication
If a patient is on immunomodulatory medications, cannabis could interfere with their effectiveness.
Photo by: Gina Coleman/Weedmaps

Expanding on how medical cannabis could benefit cancer patients, Rae said, “Not all cancers are alike, but many of them do respond to the molecules found in cannabis by one or more key mechanisms (limiting cell size, cell survival, cell proliferation, angiogenesis, metastases, etc).”

In addition, Rae pointed out that medical marijuana can serve as an indirect treatment for the symptoms that cancer patients often experience, which are also symptomatic of many chronic diseases. Some of these symptoms may include:

  • Pain
  • Anxiety
  • Sleep issues
  • Decreased quality of life
  • Chemo-induced problems

Rae said, “Chemotherapy often causes nausea, and cannabis is great for chemo-induced nausea and vomiting. Chemo can also cause neuropathy, which is very painful. Cannabis is good for neuropathic pain.”

man smoking joint
Tobacco smoking, and co-smoking tobacco and cannabis is definitely associated with lung cancer, but cannabis smoke alone does not appear to cause lung cancer.
Photo by: Gina Coleman/Weedmaps

One question that may concern cancer patients is whether smoking cannabis can cause lung cancer. Vaping has also received a negative reputation in the media, but are the worries based on fact? Rae responded, “Tobacco smoking, and co-smoking tobacco and cannabis is definitely associated with lung cancer, but cannabis smoke alone does not appear to cause lung cancer.”

However, anyone with conditions such as emphysema or chronic bronchitis should refrain from smoking cannabis, regardless of any cancer diagnosis. 

The bottom line on cannabis and cancer

Medical cannabis has shown to be a helpful supplemental treatment when it comes to managing cancer-related pain and chemotherapy-induced nausea and improving overall quality of life for some patients. Each cancer diagnosis is unique, and patients should discuss the prospect of medical marijuana with their physicians before beginning a regimen. 

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The information contained in this site is provided for informational purposes only, and should not be construed as medical or legal advice. This page was last updated on October 26, 2020.