It is also important to note that some studies have shown that CBD might interfere with how your body processes cancer drugs, called a drug interaction. This might make cancer treatments more toxic or make them less effective. More research is needed on these effects, too. For these reasons, always tell your oncologist if you’re thinking about using CBD before you take it.
To date, no large-scale studies have shown CBD to have benefits for the treatment of people with cancer. Most studies that have been done evaluating CBD as a cancer treatment were in mice or in human cells in the lab. For instance, there are some studies that have shown that CBD inhibits the growth of cancer cells in mice with lung cancer or colon cancer. Another study showed that CBD, together with THC, killed glioblastoma cancer cells in the lab. However, no studies have been conducted in people with cancer.
There is much about CBD that is still unknown. It has largely gone unstudied because, until 2018, it was considered a schedule I drug by the U.S. Drug Enforcement Administration (DEA). A schedule I drug is a drug that has been declared illegal by the DEA because of safety concerns over its potential for abuse and because there is no accepted medical use for it. Then, in September 2018, the DEA updated CBD’s status to become a schedule V drug. Schedule V drugs have a lower potential for abuse and are deemed to have some medical use.
Can CBD help people with cancer?
CBD is 1 of the hundreds of chemicals found in the flowering cannabis plant. CBD does not have the psychoactive, or mind-altering, effects of another chemical found in cannabis called tetrahydrocannabinol (THC). THC is the chemical that causes people to experience a “high.” CBD, on the other hand, is being used by some to help ease pain, anxiety, and sleep issues.
There is currently 1 CBD treatment approved by the U.S. Food and Drug Administration (FDA) called Epidiolex, which is used to treat a rare and severe form of epilepsy in children. There are not currently any FDA-approved CBD medications for treating cancer or side effects of cancer treatments.
There are 2 synthetic cannabis medications, nabilone (Cesamet) and dronabinol (Marinol or Syndros), that are FDA-approved to treat nausea and vomiting related to chemotherapy. These medications are made in a laboratory.
Yet there’s very little research around CBD and its use in treating people with cancer. Here’s what to know about what CBD is and what science currently shows about whether it’s safe and effective for people with cancer to use.
© 2020 The Author(s) Published by S. Karger AG, Basel
To compare the efficacy of pure CBD compared to the most potent CBD oil preparation (Oil A), we performed dose effect experiments for each preparation based upon the CBD content. As shown, in Figure 3 and Table 3, the efficacy of CBD was generally better than that observed for Oil A; however, this difference only achieved statistical significance between pure CBD and Oil A in the CRC cell line SW480.
The Cannabis sativa plant (marijuana and hemp) has a long history of use in medical therapy. There are records of the use of this plant dating back almost 5,000 years ago in China to treat gout, malaria, constipation, rheumatism, and other conditions . Extracts of C. sativa contain a large number of phytochemicals such as terpenes and flavonoids, as well as a unique class of molecules known as cannabinoids. There are over 100 different known cannabinoids, with the 2 most abundant being delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Unlike THC, CBD does not produce euphoria but has been shown to modulate the activity of THC and have anti-inflammatory and analgesic activities [2-4].
Our results – showing that there does not appear to be an entourage effect when comparing pure CBD to high CBD content hemp oils – are in contrast to a recent study in breast cancer cells that showed botanical drug preparations were more efficacious than pure THC at reducing cell viability . We also conducted an experiment in which CRCs were treated with equal amounts of CBD and THC in media containing serum and did not see any further enhancement of the toxic effect of CBD alone (data not shown). However, there are several differences between our study and the study of Blasco-Benito and colleagues . First, our study did not serum-starve cells, and this likely accounts for the difference in findings. Cannabinoids have been found to be greater than 90% bound to protein in blood samples from human pharmacokinetic experiments and so, in the absence of plasma proteins, the effective concentration of free drug will be much higher. In the present study, we chose to avoid serum starvation because it less accurately reflects the human system and renders the cells more fragile and sensitive to drug treatment [33-36]. Second, the 2 studies examined different principal cannabinoids; here, we examined the effect around CBD oil and attendant additional phytochemicals, and the former study focused on THC. Interestingly, their plant extract did not contain any CBD . We have not observed an ability of pure THC to reduce viability in CRC cells , nor melanoma or GBM cells (data not shown). Several studies have reported that THC can reduce cancer cell viability; however, these studies were all performed in low or no serum conditions [10, 19, 21, 22]. In agreement with these studies, we did find that THC can reduce cell viability in CRCs to levels similar to CBD under no serum conditions (data not shown) and so, our findings are not in conflict. However, in the presence of serum, we do not see an effect of THC, and this is in agreement with a study that showed that cell viability of cancer cells in serum was not impacted by THC at concentrations less than 63.5 μM.
For studies involving pure CBD (vs. control), the Student’s t test was used to determine statistical significance and a p ≤ 0.05 was employed as the threshold for significance. For the studies involving the various CBD oils, an ANOVA was first performed followed by a Student’s t test, if appropriate, with the same threshold as above.