Glaucoma, pain, nausea, loss of appetite, epilepsy and multiple sclerosis; the list of ailments that medical marijuana shows promise in treating seems to be steadily growing. But what about the disease most people seem to be interested in, cancer? Despite an abundance of anecdotal evidence supporting its use, clinical trials are virtually non-existent.

But cell culture and animal studies for one type of brain cancer, glioma, have been so promising that scientists are now crowdfunding for a new human study to investigate its potential therapeutic benefits. And given the overwhelmingly positive public response that this same start-up crowdfunding platform, Walacea, received earlier this year when reaching out for funds for a human LSD brain imaging project, it seems likely that the campaign will be a success.

“Donating to cannabis medical research is essential to highlight the potential of cannabinoids to treat a range of conditions,” Jorge Cervantes, horticulturalist and medical cannabis advocate, said in a statement.

But if these cannabinoids --the biologically active compounds found in cannabis plants-- hold so much promise, why is public money needed to fund such important research? Like heroin and LSD, marijuana remains a Schedule 1 drug, meaning it is either deemed as having no accepted medical treatment use or there is a lack of accepted safety for its use. That’s despite the fact that it has been legalized for medicinal or personal use in some US states. Unfortunately, the resulting controls placed on drugs within this category makes scientific research into their therapeutic uses virtually impossible.

“The law is there to protect people,” Natalie Jonk, founder of Walacea, tells IFLScience. “Yet by making cannabis a schedule 1 drug, it makes people who wish to benefit from its medicinal properties criminals.” Cancer patients wishing to use the drug therapeutically are also forced to rely on forums and personal experience, which is dangerous as doses are not based on clinical evidence.  

Gliomas are a common type of brain cancer, accounting for around 45% of cases. Because they have a tendency to grow into normal brain tissue, surgical removal is exceedingly difficult and often bits of tumor remain despite a surgeon’s best efforts, offering the opportunity for the cancer to return or spread to other body sites. This, combined with the fact that this organ is inaccessible to many therapeutic agents, thanks to its protective blood-brain barrier (BBB), means that gliomas are notoriously tricky to treat.

Here’s where cannabis comes in: cannabinoids can rapidly cross the BBB, exerting various effects by mimicking natural substances produced by our body, the endocannabinoids, which stick to and activate so-called cannabinoid receptors. One such effect is their apparent antitumor activity, demonstrated in various different cancerous tissues in the lab.

Encouragingly, cannabinoids seem to cause cells that drive glioma progression and recurrence, called glioma-initiating cells, to self-destruct in the lab, a process known as apoptosis. If the substances can do the same things in glioma patients, then scientists are hopeful they may represent a novel way to tackle these cancers. But until scientists conduct proper controlled trials, we won’t know whether this is the case or not.

Hopefully, if this proposed trial goes ahead, we may finally glean some long-anticipated answers. The program is due to commence this Autumn, conducted across 4-6 Spanish hospitals. It will involve between 30-40 glioma patients who will be administered cannabinoids in combination with other anticancer drugs.

Alongside the crowdfunding effort, which seeks to raise £60,000, volunteers are hoping to raise an additional £200,000 from a sponsored 420 kilometer bike ride, which ends on 14 June.