Common Objections
Common objections are often raised from listeners when discussing the anticancer effects of cannabis. Indeed, anyone who isn’t intimately familiar with this topic should rightfully be skeptical. Below are potential responses to objections.
Objection: Preclinical evidence with cells and animals rarely translates to humans.
Response: That is correct. What makes cannabinoids different is the fact our own self-made endogenous cannabinoids have been shown to kill cancer cells through similar mechanisms as plant cannabinoids like THC. For example, our main endocannabinoid, anandamide, has been shown to kill cancer cells by activating CB1 receptors on the surface of those cells, just like THC. Two preclinical studies also had a clinical component in which humans injected with THC experienced the same anticancer effects as the cells and mice (“Cannabinoids Inhibit Glioma Cell Invasion by Down-Regulating Matrix metalloproteinase-2 Expression” and “Cannabinoids Inhibit the Vascular Endothelial Growth Factor Pathway in Gliomas“. There is also a placebo-controlled study on glioblastoma which found a significant difference in survival (6 months) between those on THC/CBD and chemotherapy versus those on placebo and chemotherapy. This can only logically be explained by the synergy between THC/CBD and the chemotherapy, as was posited by the principal investigator herself. Furthermore, other preclinical evidence has translated extraordinarily well to humans, such as CBD for treating genetic epileptic disorders like Dravet syndrome that cause seizures. Prior to human use, the only preclinical studies showing CBD had an antiseizure effect tested CBD in mice injected with chemicals that stimulated seizures. Such seizures are far less complex than those produced by Dravet syndrome. However, CBD has been shown in several double-blind studies to stop seizures, sometimes with 100% efficacy despite the failure of all pharmaceutical options, in Dravet syndrome and Lennox-Gastaut syndrome, another epileptic condition. Quite interestingly, an animal study exploring CBD for Dravet only came well after the initial human reports. If the preclinical evidence translated so well to humans in such complex cases involving dysfunctions of the human brain, it is much more likely the preclinical cancer evidence would translate too.
Objection: Evidence not reported in medical journals is worthless.
Response: The nature of the media-reported evidence in this case is extraordinary. Cases have been reported by thousands of people across the world, across many years, from many sources. Doctors, caregivers, corporations, dispensaries, and patients themselves have reported these effects in detail. The chances that every single one of them is lying or grossly misunderstanding the nature of the situation (as in they think cannabis healed them but it was really something else) is absurd. It is tremendously improbable that all of this is coincidence, especially with hard scientific evidence that simply can’t be made up.
Objection: What about the side effects of high-dose cannabinoid therapy
Response: This is a legitimate concern. The use of high doses of THC has been linked to some issues, particularly psychological ones, although whether the associations are cause-related or merely correlated has not been proven. However, based on years of reports from cancer patients using high doses of THC, there do not seem to be overwhelming adverse effects. Furthermore, most patients do not need to stay on high doses of THC for an extended period of time. Yet further, many patients can significantly reduce the intake of THC by using CBD as well. At least one study shows that high doses up to 700mg of CBD per day are safe, and there is some indication that CBD alongside THC may counteract negative effects. Nonetheless, more long-term research is definitely needed. Considering that many far more dangerous pharmaceutical drugs are regularly approved without such long term research, there is no reason to hold back on allowing this historically safe medicine.
Objection: What about studies showing cannabinoids promotes cancer cell growth?
Response: There are only a few studies showing cannabinoids, mainly THC, can promote the growth of some cancers, such as this one with THC and a subtype breast cancer. However, these studies are overwhelmingly dwarfed by those showing anticancer effects, and even the linked study above has been countered by others showing THC fighting the same subtype of breast cancer. Large epidemiological studies of cannabis users show no increased risks of cancer, besides potentially testicular cancer, and potentially a protective effect, so in the general population THC is clearly not causing cancer at a grand scale. In one study where isolated cannabinoids were shown to stimulate cell growth of only one of the several tested cell lines, the effect turned to reducing cell growth at the highest dose tested, and the CBD-rich whole-plant extract lacked a pro-proliferative effect even at the lowest dose tested, suggesting anticancer synergy. Those using cannabinoids for cancer treatment use far higher doses than recreational users, so if the recreational users are not experiencing increased cancer rates, it is highly doubtful higher doses would feed cancer. And indeed, the vast human evidence supports it does not.
Objection: How can cannabis be claimed as a general treatment for cancer when there are hundreds of types of cancer?
Response: Preclinical studies have showed that phytocannabinoids have anticancer effects against all the major types of cancer – brain, breast, colon, liver, lung, pancreatic, prostate, skin, and more. Other rare cancers like Kaposi’s sarcoma, rhabdomyosarcoma, and cholangiocarcinoma have also been shown to respond. There are surely some subtypes of these cancers which are resistant, and this will be revealed with further research. For example, diffuse intrinsic pontine glioma (DIPG) is a form of brain cancer which appears resistant to cannabinoids. This seems to be due to the tumor’s location in the brainstem, which has virtually no cannabinoid receptors. Other tumors with low cannabinoid receptor expression may be harder to treat. Nonetheless, even with DIPG, significant life extension has been reported with cannabis therapy, such as this report. In any case, the fact some cancers are resistant to cannabinoid therapy is certainly no excuse to prohibit it altogether, especially since it seems far more cancers are responsive. Furthermore, although cancers are caused and fueled by a wide variety of factors, at its heart cancer is abnormal cells rapidly dividing, failing to die, and spreading throughout the body. The endocannabinoid system may have a role in controlling this fundamental process, which may apply to all cancers. While this is theoretical and far more research is needed, the existing preclinical and human evidence suggests this is not as far-fetched an idea as it seems.
Objection: What about the failures? Are all the successes cherry-picked to obscure a huge number of failures? After all, just the successes get reported on.
Response: It is not necessarily true that only successes get reported on. Many patients who initially were reported to have successful treatments later passed away, although the details of most such cases usually suggest better-than-expected life extension. More importantly, there are dozens of caregivers who have worked with dozens to hundreds of cancer patients who have seen anticancer effects apply to most of their patients. It is unlikely there would be so many reported successes if the success rate was tremendously low. Also, given the fact that every single human possesses endocannabinoids which are known to kill cancer cells, it is not unreasonable that cannabis extracts would work for many people with many cancers. Nonetheless, pure failures with no level of success are rarely reported, so the fact that cases are cherry-picked is certainly the strongest objection. However, all available evidence suggests that there is no massive repository of failures being hidden, and the existing evidence is abundantly clear that cannabis is producing anticancer effects in many people.
Objection: If cannabis could really fight cancer, how come we don’t already know and it’s not already used?
Response: Researching cannabis for any purpose anywhere in the world has been difficult since most countries have prohibited cannabis. While research of medical cannabis is ostensibly legal in many places, in practice, human research has been very limited due to financial constraints and the stigma against cannabis. As an example, there are numerous barriers to conducting research and trials in the United States. Furthermore, any human clinical trials, let alone for a prohibited and stigmatized drug, are inherently difficult to conduct.
Most human studies that have been conducted use relatively low doses of THC and/or CBD, and have tended to examine symptomatic parameters like pain rather than diagnostic parameters like cancer cell counts.
The doses needed to achieve direct anticancer effects with cannabis may be the biggest reason for lack of knowledge. While some cases involve the use of low doses of cannabinoids, the vast majority of patients who have reported anticancer effects used sustained, high doses in the hundreds of milligrams range for several months. The vast majority of medical cannabis users have historically either smoked/vaporized medical cannabis, or used low-dose edibles such as brownies. The evidence currently suggests these methods do not have significant anticancer effects. Therefore, since the vast majority of patients have not used high dosing protocols, how would they know cannabis could have a direct anticancer effect? It wasn’t until around 2008 that knowledge of high dosing protocols began to grow substantially (due to the release of a documentary on the subject called Run From the Cure), which triggered the growth of further human evidence of anticancer effects. The evidence is just now catching up to those earliest claims. While that initial documentary had many problems and is essentially irrelevant when considering the current evidence, it undeniably played a huge role in raising awareness about the possibility of direct anticancer effects with cannabis.