Cannabis and Cancer: What Does the Research Say?

Cannabis and cancer are increasingly becoming linked. More and more people are starting to read about the supposed benefits of cannabis for cancer treatment. So far, it has been shown to impact cancer-related symptoms, including reducing nausea, pain, and overall tumor growth.

Further research needs to be undertaken to understand the harms and safety of cannabis and cancer. However, there is exciting potential for its medical use.

What are the potential benefits?

A number of positive outcomes have been associated with cannabis and cancer treatment. These include the easing of symptoms associated with cancer treatment, such as nausea and weight loss.

Reduced nausea

One of the most consistently reported positive impacts of using cannabis for cancer treatment is that it can reduce nausea, a common side effect of chemotherapy. This associated nausea can lead to vomiting and a decreased overall appetite, meaning that many people with cancer also experience high levels of weight loss.

Antiemetic drugs, such as corticosteroids and dopamine antagonists, can be effective at reducing nausea symptoms. But when ineffective, a number of studies have shown that cannabis may be a suitable substitute.

Conducted in 2010 and published in the British Journal of Clinical Pharmacology, a randomized controlled clinical trial of cancer patients found that cannabis was “well-tolerated and provided better protection against chemotherapy-induced nausea and vomiting.”

Increase appetite and decreased weight loss

Cannabis can also help people with cancer increase their food intake and subsequently minimize excessive weight loss. Published in Therapeutic Advances in Medical Oncology in 2019, a review of existing clinical evidence found that evidence was “beginning to emerge to support the use of cannabis for treating chemotherapy-induced nausea and vomiting, loss of appetite, pain, and chemotherapy-induced peripheral neuropathy.

However, the review also concluded that, currently, there was “not yet data available to specify the optimal cannabis-derived treatment, dose, or delivery system.”

Reduced pain

Cannabis’ pain-relieving properties are thought to be linked to its anti-inflammatory properties and its ability to activate CB1 receptors in the brain. The activation of these receptors is thought to increase opioid receptor activation directly, allowing for pain relief. Further research needs to be conducted into the exact mechanisms by which this occurs and the potential harms of this form of pain relief.

Decreased tumor growth

There is also some evidence that cannabis can slow tumor growth. A number of animal models and cell culture studies have demonstrated the potential antitumor effects of cannabis. One 2017 paper, for example, demonstrated that high doses of CBD and THC could significantly regress tumors in animal models. And a 2018 study showed that, when treated with cannabis compounds and chemotherapy, mice with pancreatic cancer survived almost three times longer than those treated with chemotherapy alone. 

But other studies have been less promising. In a more recent paper, CBD managed to reduce the size of tumors in mice, but its effects still paled in comparison to those of cisplatin, a more conventional chemotherapy medication.

Published in the Journal of Pancreatic Cancer last year, a review of the relevant literature found that cannabinoids, synthetic or cannabis-extracted, can reduce tumor growth and induce tumor cell death. However, it concluded that the data on treatment dosing and precise modes of action were lacking.

What are the risks?

There are some positive correlations between cannabis and cancer, and they appear to be promising options for cancer treatment in the future. However, it is also important to understand the potential risks associated with therapeutic cannabis use.

Immune system suppression

Cannabis has been shown to downregulate the immune response by acting on T cells in the immune system – a kind of immunosuppression that could prove dangerous for cancer patients to risk.

Side effects

The World Health Organization has stated that cannabis has a good safety profile, but there are still a number of known side effects associated with cannabis use. These can include fatigue, diarrhea, and changes in weight.

In addition to this, cannabis is known to interact with a wide variety of drug classes. These include antidepressants, antibiotics, blood thinners, epilepsy medication, and even certain chemotherapy drugs. This can seriously diminish their safety profile. Further research and trials need to be undertaken in order to determine the safety of cannabis as a viable cancer treatment.

The bottom line

The potential of cannabis as a cancer treatment is becoming increasingly investigated. Cannabis has shown potential for reducing a range of cancer symptoms, including nausea, appetite loss, and pain. Plus, cannabis has been linked to reducing tumor growth and inducing cancer cell death.

While this is promising, further research needs to be done to assess the potential harms and adverse effects of the long-term use of cannabis as a cancer therapeutic. However, there is promise for the potential use of cannabis for cancer treatment in the future.