Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“Cannabis and cancer: reality or pipe dream” quackery? “Among alternative cancer treatments, cannabis inhabits a peculiarly politicised position, hailed as a suppressed panacea by some, denounced as a [dangerous] drug by others.” “At the far end of the spectrum are those who insist cannabis…helped…cure their cancer.” “The promise, and even the hype, can reach hysterical proportions, with claims of cannabis cancer cures circulating in cyberspace at a furious pace.”

The problem is that sometimes a patient will have a cancer that’s curable with conventional therapies, like you could cut it out before it spreads, but forgoes that treatment in favor of something that just got good online testimonials.

Yes, cannabis compounds like THC can reduce brain tumor volume in mice, or suppress cancer cell growth in a petri dish. But, it turns out, “mice and rats are not people, and what is observed in vitro does not necessarily translate into [human] clinical medicine.” Why not just give it a try, though? Because there’s other evidence that cannabis compounds “may encourage cancer…growth.” Like THC inhibiting antitumor immunity, or inducing cancer cell proliferation, “enhanc[ing] breast cancer growth and metastasis by suppression of the antitumor immune response.” Yeah, but in “mouse mammary” tumors. You don’t know what happens in people…until you put it to the test. But because of legal reasons, few human studies have been done. But thankfully, “after years of [a] deep freeze on cannabis-related research, funding, and materials, a thaw is starting.” But where do you even start?

Well, if cannabis compounds—cannabinoids—”are postulated to have a potential anticancer effect working through the [cannabinoid] receptor[s], it would follow that [trying it on cancer of] the brain,” where the receptors are most densely concentrated, “would be a good place to start.” Okay. Well, “[o]ne of the most devastating forms of cancer is glioblastoma,” a fast-growing type of malignant brain tumor. And, that’s the first cancer that was put to the test.

Cannabis compounds sometimes inhibit tumor growth in lab animals. However, any antitumor effects have never been tested in humans. So, here we go, the first clinical study on cancer: specifically, a pilot study “in which nine patients with recurrent glioblastoma”—meaning they had the tumor cut out; they had the radiation treatments; but the cancer is back and is growing. Then, they administered the THC straight into the tumor. Basically, they went back into surgery, had a scoop carved out of the center of their tumors, and they stuck a catheter in the middle, with the other end sticking out of their heads so they could drip the THC straight into the tumor with a syringe. THC was already tested on biopsy specimens, and showed it was able to kill some of the cancer cells off in a petri dish. So, what happened when it was tried on the patients themselves? The patients all died, in a matter of months.

In a few patients, it seemed to work for a few weeks—maybe—but then the tumor took back off despite repeated treatments. This looks like their most dramatic result. Here’s where the tumor started before the treatment, and at four weeks had dramatically shrunk down. 35-year-old guy. Oh, the whole family must have been beside themselves. But then it came back with a vengeance, and despite more infusions, got worse, and then he was gone. With no control group, the effect of the treatment on overall survival is unclear.

This was both the first clinical trial on cancer, and the only clinical trial on cancer, even though it was published over a decade ago. But the good news is: “there are more than 15 trials” currently underway—perhaps the most exciting of which is a phase 2 trial in Israel, again looking at advanced cancers that are progressing despite all standard treatments. In the meanwhile, if you are undergoing a standard treatment like chemo, at least we know that cannabis may help with some of the side effects.

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