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Does Marijuana Fight Cancer? Use Marijuana if You Want To, but Don’t Presume it’s an Effective Cancer Treatment

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I live in the state of Washington, which now has legalized marijuana.  Even before then, it wasn’t especially hard for motivated people to get.  Like many other physicians, a socially liberal lot overall, I have been fine with it and haven’t considered it in the same league as other (previously, and state-dependent) street drugs. It can help fight nausea and pain, and responsible people just may want to use it without needing to give an explanation.

I have no real issue with marijuana, but I sure have a lot of patients who read about or are told by family and friends about how effective cannabis oil or other forms of marijuana may be as anti-cancer therapy.  Here, it fits the pattern of MANY other complementary and alternative medicines, ranging from low dose naltrexone to dichroloacetate (DCA):

  1. encouraging results from lab-based models
  2. lots of anecdotal cases of “__ saved my life, and it can save yours, too!!”
  3. Years to decades of claimed benefits despite absence of true evidence in the form of appropriately done clinical data in human cancer patients
  4. economics that make it infeasible to do actual clinical studies but still provide a very lucrative business by selling to the end consumer

Medical Marijuana

Let’s explore these issues. It’s important to know that it’s great when a treatment looks favorable in test tube or animal models of cancer, but there are another 20 steps between that level of success and having a truly beneficial anti-cancer treatment for humans. So while my son may be setting the pace in his 3rd grade class, introducing him to people as a future valedictorian is a tad premature and presumptuous.  About half of the condiments on your refrigerator door have anti-cancer properties when tested in one pre-clinical, lab-based test or another — it’s a low bar, because the conditions are very artificial. There’s a reason the FDA doesn’t approve drugs based on promising anti-cancer activity in lab tests — it means nothing except that it’s worthy of a lot more testing to see whether it’s actually useful. Or you can just stop there and use the weak evidence peppered with a few impressive stories to market the hell out of some complementary medicine you’re peddling.

Along with a plausible premise from some references to lab-based work to provide a hint of real science, the other element that fuels claims of a miracle cure are anecdotal cases of patients doing well. There are two main versions of this illustrative case. The first is a patient who takes a known potentially effective therapy along with the unproven therapy, do well, then credit the wonder of their good outcome not to the proven standard treatment but to the unproven magical element added to it.  Standard treatments work, which is why they became standard treatments.  One of the most common ways we test new treatments is that we give standard treatment to half of the patients, standard treatment plus new treatment X to half of the patients, then compare how everyone did. However, you can only tell how effective the added intervention is by looking at large groups that did vs. did not get the treatment added to the standard. Because we know that lots of patients happen to do well, and lots of patients happen to do less well, there is no value in trying to ascribe a good or bad result in one patient to the novel intervention. 

The other anecdotal case is someone who was told that no further treatments would help and that they’d be dead in 3 months, started miracle drug X, and they’re still alive years later.  It’s certainly possible that some people may be very effectively treated from it, but remember that a broken clock is right twice per day: even if a treatment happens to work well for one patient, how many patients aren’t featured in a testimonial? Did 500,000 other patients try that therapy and die, and therefore aren’t a featured story?  There are also patients who are simply misdiagnosed and may have an infection presumed to be a cancer, told they have recurrence, then get better while on miracle drug X not because it’s a miracle, but because they never had metastatic/incurable cancer.  Other patients have very slow-growing, even barely perceptibly growing cancer that some physician will mistakenly say is likely to limit a patient’s life to months: no matter what that patient does or doesn’t do, they’re going to do well, but if they happen to have bought into miracle drug X, they’re going to become an advertisement for it simply because they were destined to do well anyway.

Marijuana has been the subject of study for decades, but there is still no evidence in any controlled studies that it helps human patients.   In this sense, it’s very similar to low dose naltrexone (LDN) and dichloroacetate (DCA), which I first wrote about more than 5 years ago and, not surprisingly, still have zealous champions but no actual compelling clinical evidence, year after year after year.  Here, I think it’s worth asking how these agents, if they were anything close to as good as they are claimed to be, can help but have thousands of cured patients.  And yet the success stories are few and very far between.

Yes, it’s true that marijuana isn’t a patent-protected agent in the Novartis or Pfizer or Genentech pipeline that has up to a billion dollars budgeted on its research and development. Could these be truly miracle drugs? Sure, absence of proof isn’t proof of absence.  But today there are other ways to actually conduct trials on drugs that won’t be developed commercially by a big pharma/biotech company.  If I wanted to really prove that some agent I believed in was truly beneficial, I’d look to a couple of sources. First, I’d try to run a trial on PatientsLikeMe that includes several dozen, ideally over 100 patients who have been on at least two prior treatments for metastatic cancer, had demonstrated progression on their last therapy in 3 months or less (to weed out the people who simply have a very indolent cancer that will do well no matter what), and have people sign up at the beginning of their trial of cannibis oil.  If more than half are still doing well without progression 6 months later, especially if some actually show tumor shrinkage on no active therapy other than their trial with cannibis oil, you’ve got a publishable result that the conventional medical world will notice. That’s not a perfect trial, but it gives us the chance to check the efficacy with an actual denominator, and it’s enough to get a foot in the door and quiet the skeptics like me.  The other option is to look for some crowd-sourcing research option like Consano to collect funds that can be used to run an actual trial with one or more credible cancer researchers who would be happy to conduct a controlled study if it is funded sufficiently.  In addition, many cancer nonprofits offer research grants of up to $100,000 to test important questions.  Have cannabis oil proponents work with a researcher to apply for research funds that don’t require a pharma company to support them.  It’s absolutely feasible.

So let’s take a step back and assess what we have now. There is some preclinical, lab-based evidence that suggests a possible benefit from marijuana, with the greatest interest and most active promotion for cannabis oil.  There are a few anecdotal cases that provide further encouragement for actually testing the idea more carefully, and otherwise these testimonials are great for selling an idea to people looking for hope.  But this isn’t meaningful evidence that marijuana fights cancer. We now have ways to test cannibis oil more thoroughly, if the people selling it and patients promoting it believe in it enough to put it to the test.  Until then, there may be many reasons to use marijuana, but its implied activity as an effective anticancer therapy shouldn’t be one of them. 


2 Responses to Does Marijuana Fight Cancer? Use Marijuana if You Want To, but Don’t Presume it’s an Effective Cancer Treatment

  • cards7up says:

    Great article! But I have to wonder about the children with brain disorders being helped by cannabinoid oil? Could it have something to do with the cannabinoid receptors in the brain? This is a trial I’d like to see done. Again, this is not cancer related, but it makes you think.

  • Dr West
    Dr West says:

    So the short answer is that I don’t know, that I do think it’s very possible that cannabinoid oil can be helpful for children with brain disorders, just as I think it’s possible that it is helpful for cancer. But I think we need to step back and review the evidence critically and ensure that it isn’t 95% testimonials, hype, and placebo effect. I don’t know if there are actual controlled studies of cannabinoid oil in the setting of childhood brain disorders, but I would be skeptical about presuming anything based on enthusiastic endorsements from parents — this isn’t to say they aren’t valid, but the placebo effect is VERY real, and it’s especially likely in people expecting to achieve very favorable results on extremely subjective symptoms. I’ve read some stories of wild-eyed hope that make me think there is NO way to trust that parent who is hell-bent on finding something positive to report after trying it in their child, even if they need to convince themselves.

    -Dr. West

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