Promising New Research on Cannabis’s Effect on Cancer

byMichael Warford4 minutes

New research into the potential medicinal uses of cannabis has picked up significantly in recent years. The fact that the social stigma surrounding marijuana is decreasing while prohibition laws are being repealed makes it easier to secure funding for more research into the plant’s medicinal benefits.

Among the most exciting aspects of this research is how cannabis may be used to treat cancer. While cannabis has long been legal for treating some of the symptoms of cancer and the side effects of cancer treatment, recent research suggests that it could also act as a powerful tool in the battle against cancer itself.

Specifically, studies show that cannabis may actually help reduce tumour size.

How Is Cannabis Currently Used in Cancer Treatment?

Cancer patients use medical marijuana to treat many of the side effects that result from cancer treatment, in particular during chemotherapy. Cannabinoids, for example, are prescribed in pill form to patients undergoing chemotherapy to reduce nausea and vomiting.

Sativex, meanwhile, combines tetrahydrocannabinol (THC), the main psychoactive compound in cannabis, and cannabidiol (CBD) in the form of an oral spray. It’s currently prescribed to relieve pain in advanced cancers in cases where opioids are ineffective.

Finally, many cancer patients suffer from a significant reduction in appetite, which can result in weight loss. Studies on animals have shown that THC can increase appetite, although research on humans has so far been limited. Nonetheless, there’s plenty of anecdotal evidence of patients using cannabis to maintain weight and stimulate appetite.


How Cannabis Helps Fight Tumours

While cannabis is currently only used to treat the symptoms of cancer and the side effects caused by treatment, more recent research shows that it may kill cancer cells and inhibit tumour growth. While saying that cannabis can limit tumour growth may sound like a dramatic claim, it’s made by no less an authority than the National Cancer Institute (NCI), which is part of the federal National Institutes of Health (NIH) in the United States. The NCI recognizes a number of studies, which show cannabis’s cancer-fighting potential.


A study of THC, for example, performed on mice showed that it can kill or damage liver cancer cells and inhibit the growth of tumours. This same study showed that THC achieves these benefits by acting on molecules that are also present in non-small cell lung cancer and breast cancer cells.

Another study found that CBD kills breast cancer cells and inhibits the growth and spread of new tumours in the breast. It does this while having little impact on healthy breast cells.

Similarly, dozens of studies have found that cannabinoids can kill glioma cancer cells, which is a type of brain cancer. And yet another study found that CBD also increases the effectiveness of chemotherapy in patients suffering from glioma by killing cancer cells while leaving healthy cells unharmed.

So why does cannabis appear to inhibit cancer cell growth? It has to do with the body’s natural endocannabinoid system (ECS). The ECS is a network of receptors located in cell membranes throughout the human body. It plays a vital role in our:

  • Immune system
  • Pain reception
  • Sleep patterns
  • Appetite
  • Memory
  • Emotions

The ECS interacts with cannabinoids, like THC and CBD, which are found in cannabis.

Once in the body, cannabinoids work as both a proapoptotic—meaning, they kill cells including harmful cancer cells—and as an antiangiogenic, cutting off the blood supply to tumours and thereby inhibiting their growth. What’s especially exciting about the latest research is that it shows cannabinoids can kill cancer cells while leaving healthy cells largely unaffected.

Research Into Cannabis & Cancer Gains Steam

It isn’t just in the fight against tumours that cannabis has shown a lot of promise. Some research also shows that cannabinoids may help prevent certain types of cancer from developing in the first place. One study, for example, found that cannabis prevents inflammation in the colon and can help reduce the risk of colon cancer.

It needs to be stressed that most of the research done so far on cannabis and cancer has been performed on mice and rats. While this research is extremely promising, it’s far too early to say whether all of the benefits seen on animal subjects will be seen on humans. Certainly, no reputable researcher or doctor is claiming that cannabis holds the cure for cancer.

But research is picking up. Recently the University of New Brunswick appointed Yang Qu, who made a name for himself at Brock University helping research and develop anti-cancer drugs, as the country’s first cannabis health research chair. St. Thomas University, also in New Brunswick, is currently searching for somebody to fill its own cannabis research chair.

Qu points out that much of the research into cannabis’s potential anti-cancer benefits have so far been focused on just two cannabinoids: THC and CBD. However, there are more than 100 other known active cannabinoids in the plant that are poorly understood, and which may have their own potential health benefits.


So, research into cannabis’s role in the fight against cancer is very much in the early stages. There’s far more about this plant that we don’t know compared to what we do know. This makes following the research so exciting. Each new study is a step towards better understanding cannabis and how it may one day be used to help fight cancer and other diseases.

Photo credit: Josh Riemer