US National Cancer Institute to fund further research on cannabis

Leading US body, the National Cancer Institute is set to fund further research to gain a “deeper understanding” of the effects of cannabis on cancer.

Despite an estimated one in four cancer patients in the US using cannabis to manage their condition, clinical research into its efficacy and risks remains limited.

But as this field of research begins to gain momentum, the US federal government is set to provide funding to promote further studies.

In a notice of special interest released last week (5 May), the National Cancer Institute (NCI) invited research applications that examine the mechanisms of cannabis and cannabinoids in cancer biology, cancer interception, cancer treatment and resistance and management of cancer symptoms.

With more and more states legalising cannabis, both for medicinal and recreational purposes, the use of cannabis has grown significantly. A 2019 survey estimated that 48 million United States individuals aged 12 years or older had used cannabis in the past year, an increase of 87 per cent from 2002.

Among cancer patients, cannabis use has also increased, with a quarter of patients thought to take cannabis to manage common symptoms like anorexia, nausea and pain. As research continues to lag behind the growing interest in cannabis as an alternative therapy, the National Cancer Institute said the notice aims to “promote research in understanding the mechanisms” by which cannabis affects cancer symptoms, biology and treatment.

The notice highlighted a number of under-explored areas of research, including cancer risk, cancer biology, cancer treatment and the links between cancer and the endocannabinoid system.

The current research on associations between cannabis use and cancer risk have have yielded limited and inconsistent results, the NCI said.

The agency noted that while cannabis smoke generates many of the same carcinogens as tobacco, studies have not shown a link between cannabis smoking and lung cancer. While there is some preliminary evidence suggesting an increased risk of testicular cancer amongst cannabis users, studies of other cancer types are limited.

The agency also said a “deeper understanding is needed about how the tumour-promoting and suppressive mechanisms of cannabinoid signalling influence cancer biological processes”.

A key piece in the puzzle is the endocannabinoid system which has been found to regulate processes including cell proliferation, motility and survival. These pathways are often dysregulated in cancer, the NCI said.

Research so far has produced mixed results. For example, a study using mouse models of a type of breast cancer, found CB2 enhances tumour growth and metastasis. Other cancer models, however, have found that cannabinoids can suppress tumour formation.

The notice stated: “Cancer cell line experiments show that THC and CBD can mediate many anti-tumour effects, including inducing apoptosis and inhibiting cell proliferation, invasion and angiogenesis.

“These anti-tumour activities have led to early clinical testing of THC and CBD for glioblastoma and prostate cancers. While preclinical studies show differing effects of cannabinoids on cancer cells, deeper understanding is needed about how the tumour promoting and suppressive mechanisms of cannabinoid signalling influence cancer biological processes.”

In a UK phase I trial in glioblastomas last year, the cannabis-based mouth spray Sativex was found to be tolerable in combination with chemotherapy, with the potential to extend survival. The research project has now progressed to a phase II trial which launched across 15 NHS hospitals in 2021.

The notice said studies that “integrate expertise from multiple disciplines, incorporate state-of-the-art, human-relevant models (e.g organoid or patient-derived xenograft models) and utilise advanced technologies and methods” are strongly encouraged to apply.

A full list of areas of research that the NCI is particularly interested in can be found here

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