The US’s National Cancer Institute (NCI) has announced it will fund several studies to help determine how cannabis affects cancer development.
In a notice published on May 5, the US government agency invited researchers to submit “applications that examine the mechanistic actions of cannabis and cannabinoids in cancer biology, cancer interception, cancer treatment and resistance, and management of cancer symptoms.”
Funding cancer research
Around a quarter of cancer patients have used cannabis for symptom management, according to the NCI. Despite this medical use, though, the evidence supporting marijuana’s anti-cancer effects is still limited.
To help address this research gap, the NCI is willing to fund studies investigating certain research areas, such as the following:
- How cannabis and cannabinoids affect cancer development, including the tumor microenvironment.
- How endogenous cannabinoid pathways influence cancer development and biology.
- How endocannabinoid signaling pathways might inhibit early cancers.
- How the mechanisms of cannabis may alleviate symptoms of cancer and cancer treatment, such as pain and nausea.
Studies that “integrate expertise from multiple disciplines, incorporate state-of-the-art, human-relevant models and utilize advanced technologies and methods” are strongly encouraged.
Cannabis and cancer
While the body of cannabis-cancer research is limited, several key studies have illuminated the effects cannabinoids can have on tumors and cancers.
One 2017 paper, for instance, demonstrated that high doses of CBD and THC could significantly regress tumors in animal models. Another 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. Ina 2019 paper, CBD was found to reduce the size of tumors in mice, but the cannabinoid’s effects still paled in comparison to cisplatin’s, a more conventional chemotherapy medication.
Concerningly, some other studies have found that, in some contexts, cannabinoids seem to increase the growth of certain cancers. A study published in 2020 found that marijuana use may be a driving factor in the rise of head and neck cancers in the US. In that study, the researchers observed that THC can activate a molecular mechanism in the body that accelerates tumor growth in patients with human papillomavirus (HPV)-positive skin cancers.
Lung cancers, on the other hand, appear to have a null association with cannabis use, despite the presence of carcinogens in cannabis smoke. As for the reasons behind this null effect, one scientific review published in 2015 posited that cannabinoids like THC counteract the carcinogens with their known tumor-suppressant effects.
Ultimately, many researchers and oncologists agree that more research is needed before a consensus can be made on cannabis’ clinical effect on reducing tumors. What is more agreed upon, however, is marijuana’s effect on treating the side effects of chemotherapy and radiotherapy.
“I write on whether oncologists should recommend cannabis and I’m a very strong proponent of it, because a day doesn’t go by that I don’t see a cancer patient with nausea, loss of appetite, pain, insomnia, depression, and I can recommend one medicine to those patients,” Donald Abrams, a doctor and professor of clinical medicine at the University of California, San Francisco, told Analytical Cannabis in 2019.
“And [cannabis] is less likely to interact with the other medications that I prescribe or my chemotherapy than standard pharmaceuticals. So, I am a huge proponent of the benefits of cannabis in symptom management.”
“What pains me is people forgoing conventional therapy that may benefit them greatly and even cure them, in favor of using these products that have absolutely no evidence to support their use,” he added. “And in San Francisco, patients pay up to $7,000 a month for these products. I just find it criminal and tragic.”
“As an oncologist in San Francisco for the past forty years, I have to say, if cannabis cured cancer, I would certainly have a lot more survivors.”