Studies on CBD oil & Cancer [Research Papers Simplified]

Each year, cancer, in its various forms, affects around 40% of the world’s population and claims every sixth life worldwide. In 2018, 17 million new cases and 9.6 million cancer deaths were reported worldwide. It is feared that by 2040, the annual figure for global cancer rates would rise to 27.5 million new cases.

It’s scary, isn’t it?

Scientists and researchers have been studying this silent killer for hundreds of years. While some lives have been saved in the process (Success rates are certainly rising!), millions perish each year.

In the midst of the plethora of cancer studies going on in the world, a tribe of scientists are trying to determine if cannabis products, specifically CBD oil, have any positive impact on the treatment and cure of cancer patients.

To help understand the impact of CBD on cancer patients, in contrast to other cannabis extracts like THC, one must first understand what CBD is and how it differs from cannabis in general.

What is CBD oil? How is it different from Cannabis oil?

Cannabidiol, or CBD, is a type of cannabinoid (1*) found in cannabis plants (plants under the Cannabis Sativa species, including marijuana & hemp) that has none of the mind-altering effects commonly associated with marijuana.

Reason: In its pure form, CBD is completely non-psychoactive, i.e. it is not a mind-numbing or mind-altering, euphoria-creating compound. CBD is only one of the over 400 chemical entities (1) found in plants of the cannabis plant, of which more than 60 are cannabinoids. Whereas, tetrahydrocannabinol (or THC), which is also found in these plants, is indeed a psychoactive cannabinoid. This is the chemical substance that is responsible for the much-hyped marijuana “high”. Note that a lot of these cannabinoids have opposing effects on the nervous system.

To make CBD oil, manufacturers first extract the cannabis oil from the plants and distills it through a different process to isolate the cannabidiol. The concentrated CBD is then mixed with coconut oil or hemp oil to create CBD oil that is used for many medicinal purposes these days.

However, CBD oil still does contain traces of THC. To minimize the level of THC in CBD oil, manufacturers extract the oil from hemp and not marijuana plant (both plants belong to the cannabis sativa family). Industrial-grade hemp oil contains only 0.3% THC.

Use of CBD oil for its various medicinal qualities is fast gaining momentum the world over. Although there are many controversies surrounding the use of cannabis extracts or cannabis products for medicinal purposes, many seem to believe CBD oil can be a good addition to the treatment of cancer.

What studies reveal about CBD oil’s effect on cancer patients

According to recent studies, using CBD, along with other cannabinoids like THC slows the growth, or even kills certain kinds of cancer cells. Some have even suggested using these cannabinoids along with the conventional treatments to improve the chances of survival and quality of life.

However, these two extracts have very different effects on people living with cancer. Given that not much research has been done on CBD’s possible therapeutic role in cancer treatment, some evidence has been found that suggests this compound can help manage some symptoms that patients suffer from due to the disease or its treatment.

Let’s look at what the studies say…

  • Stimulates appetite, alleviates nausea – Or does it?

Cancer patients undergoing treatment, especially chemotherapy, often suffer from its side effects that include nausea, vomiting, and loss of appetite, leading to a substantial loss in body weight.

It has been noticed that when patients ingested cannabis, it helps alleviate these symptoms, enabling them to eat better and maintain healthy body weight. However, NO CLEAR EVIDENCE has been found suggesting CBD alone could do that.

In fact, the anti-nausea effect seems to come from THC, rather than from CBD. If you are planning on trying cannabis to reduce nausea, you should be prepared for the psychoactive (inebriating and euphoric sensation) effect of THC.

Nonetheless, some studies (2 & 3) in this connection did conclude that cannabidiol has an indirect anti-emetic (or anti-nausea) effect on patients fighting with the side effects of chemotherapy, thus making the overall treatment a bit more bearable. In these studies, CBD was found to curb the vomiting tendencies by indirectly activating certain receptors responsible for controlling the part of our nervous system linked to nausea.

However, a Phase II clinical trial (4) conducted on humans showed that Sativex, an oral spray containing THC and CBD in a 1:1 ratio, can be used alongside regular anti-nausea therapies to effectively control delayed chemotherapy-induced nausea and vomiting.

Besides, THC is well-known for its appetite-promoting capabilities. (5, 6)

This only goes to prove that CBD alone can’t do much to help a cancer patient overcome nausea.

  • Evidence of CBD’s potential in relieving pain

Cancer, in whichever form you may be suffering from, does cause a lot of pain, and so does its treatment. Pain due to cancer is generally caused by inflammation, pressure on internal organs, or nerve injury. At times, the pain may get so severe that no opioids, which are powerful pain relievers, would work.

In such cases, CBD may be successfully used alongside the usual treatment to help relieve the pain. It can even curb the painful side effects of certain chemotherapy drugs that cause muscle and joint aches, headaches, and stomach cramps.

CBD has been found to have anti-inflammatory properties that help in indirectly help in reducing pain. This is particularly true to some patients who suffer swelling in their hands and feet due to chemotherapy treatments. Cannabidiol indirectly interacts with the endocannabinoid system’s CB2 receptors, thus suppressing the inflammatory response to chemotherapy through multiple mechanisms (7, 8 & 12).  

In this connection, scientists have found a clear indication of rats, suffering from an inflamed paw, reacting positively to CBD (13). It apparently also has anti-arthritic qualities. In this study, CBD was administered orally (5–40 mg/kg) to the affected rat once a day for 3 days after the onset of acute inflammation. By the fourth day, the swelling was almost gone.

Besides, studies (9) have also discovered CBD’s role in preventing neuropathic pain (due to nerve damage caused by cancer) and thermal sensitivity. What’s more, it also does not negatively impact the functioning of the nervous system or the effectiveness of the chemotherapy treatment. Researchers have concluded that this is possible because of CBD’s strong influence (10) over 5-HT1A receptors that control nerve-related pain (11).

On the other hand, THC directly acts on CB1 receptors to alleviate pain resulting from nerve damage.  This too deduces that CBD alone may not be entirely capable of reducing pain caused by the disease or its treatment, although it does have a substantial impact.

Can CBD impede cancer cell reproduction?

Opinions among scientists and researchers regarding CBD’s potential as a cancer cell growth-inhibitor are divided.

  • A recent study has confirmed that CBD when used alongside chemotherapy, inhibits the rate at which cancer cells multiply and even triples the survival rate of mice with pancreatic cancer (14). More clinical tests need to be done before CBD can be used as a complementary treatment for patients with pancreatic cancer, a potent killer of the present time.
  • While a study in 2013 (15) reinforced the opinion that a combined therapy regime decreases multiplication of cancer cells, some other research has shown that CBD Is a potent inhibitor of breast cancer cells reproduction (16).
  • Talking about curing cancer, Polish authors of a 2016 study, titled, ‘Cannabinoids – a new weapon against cancer’, concluded that cannabinoids can inhibit the growth of different types of tumor cells, both in test tubes and in animal models. They were, however, quick to add that certain dosages or types of cannabinoids might actually suppress the immune system, in turn allowing the tumor cells to grow and multiply unchecked.  

No evidence of CBD oil being a cancer-preventive drug

The handful of studies conducted on CBD (and cannabis in general) and its potential as a cancer preventive drug has been inconclusive at best.

  • A 1997 (17) study of 64,855 male patients (aged 15-49 years) of a hospital in California, USA, found that cannabis use did not increase the risk of tobacco-related cancer among these men, whereas it did increase the risk of prostate cancer among non-tobacco smokers.
  • A 2015 study yielded more promising results. The researchers found that cannabis users had a 45 percent lower risk of developing bladder cancer (18).

Although cannabis smoke still produces carcinogens (cancer-promoting substance), sufficient data to establish the connection between inhaled cannabis and cancer aren’t still available. Whereas, ingesting CBD eliminates the chances of exposing the body to carcinogens altogether.

But this can’t reason enough to use CBD oil as a cancer-preventive measure. Neither can it do much to cure you of cancer all by itself. In the absence of more extensive research in this regard, it is best not to experiment with cannabis or CBD oil on yourself, without your doctor’s supervision.

An Overview: CBD’s Palliative Quality

Although CBD’s popularity as a therapeutic drug is rising quickly, one cannot simply go along with it while dealing with a disease as serious and life-threatening as cancer. He should always consult his doctor before using CBD, any other cannabinoid or even any other alternative drug. Combining different therapies may seem encouraging. But, self-medicating may give way to counter-productive results.

While CBD admittedly does help alleviate some of the symptoms of cancer and side-effects of its conventional treatment, it is, at best, only a palliative drug for now. But, several scientists are optimistic that long-term investigation and research may reveal CBD’s potential as a cancer-curing drug. But for now, it’s best to stick to the conventional methods of treatment for cancer.  

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Notes:

1*: Cannabinoid: Cannabinoids are chemical compounds that act directly and/or indirectly on the cannabinoid receptors of the endocannabinoid system (ECS) to help the body maintain stability and health. Our bodies make their own cannabinoids – called endocannabinoids because they are produced internally – to work on cannabinoid receptors, while CBD and THC are cannabinoids found in nature, hence called phytocannabinoids. Our body’s endocannabinoid system that responds to the cannabinoids with the help of its cannabinoid receptors was discovered during the ongoing research on cannabis in 1988; hence the name.  

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Relevant links:

1: Cannabis, a complex plant: different compounds and different effects on individuals https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736954/

2: Regulation of nausea and vomiting by cannabinoids and the endocannabinoid system https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3883513/

  1. Cannabidiol, a non-psychotropic component of cannabis, attenuates vomiting and nausea-like behaviour via indirect agonism of 5-HT1A somatodendritic autoreceptors in the dorsal raphe nucleus https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3423241/

4: Preliminary efficacy and safety of an oromucosal standardized cannabis extract in chemotherapy-induced nausea and vomiting. Duran M, Pérez E, Abanades S, Vidal X, Saura C, Majem M, Arriola E, Rabanal M, Pastor A, Farré M, Rams N, Laporte JR, Capellà D; Br J Clin Pharmacol. 2010 Nov; 70(5):656-63. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2997305/

5: Endocannabinoids in the regulation of appetite and body weight

https://www.ncbi.nlm.nih.gov/pubmed/16148436

6: Cannabinoids and appetite: food craving and food pleasure https://www.ncbi.nlm.nih.gov/pubmed/19367510  

7: Naguib M, Diaz P, Xu JJ, Astruc-Diaz F, Craig S, Vivas-Mejia P, et al; MDA7: a novel selective agonist for CB2 receptors that prevents allodynia in rat neuropathic pain models. Br J Pharmacol. 2008;155:1104–1116. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2597252/

8: Rahn EJ, Zvonok AM, Thakur GA, Khanolkar AD, Makriyannis A, Hohmann AG; Selective activation of cannabinoid CB2 receptors suppresses neuropathic nociception induced by treatment with the chemotherapeutic agent paclitaxel in rats. J Pharmacol Exp Ther. 2008;327:584–591. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682949/

9: Sara Jane Ward, Sean D McAllister, Rumi Kawamura, Ryuchi Murase, Harshini Neelakantan, and Ellen A Walker; Cannabidiol inhibits paclitaxel-induced neuropathic pain through 5-HT1A receptors without diminishing nervous system function or chemotherapy efficacy https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969077/#b56

10: Russo EB, Burnett A, Hall B, Parker KK. Agonistic properties of cannabidiol at 5-HT1a receptors. Neurochem Res. 2005;30:1037–1043. https://www.ncbi.nlm.nih.gov/pubmed/16258853

11: Colpaert FC. 5-HT(1A) receptor activation: new molecular and neuroadaptive mechanisms of pain relief. Curr Opin Investig Drugs. 2006;7:40–47. https://www.ncbi.nlm.nih.gov/pubmed/16425670

12: Cannabinoids, Endocannabinoids, and Related Analogs in Inflammation; Sumner H. Bursteincorresponding author and Robert B. Zurier; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664885/

13: Naunyn-Schmiedeberg’s Archives of Pharmacology. March 2004, Volume 369, Issue 3, pp 294–299 | Oral anti-inflammatory activity of cannabidiol, a non-psychoactive constituent of cannabis, in acute carrageenan-induced inflammation in the rat paw https://link.springer.com/article/10.1007%2Fs00210-004-0871-3

14: GPR55 signalling promotes proliferation of pancreatic cancer cells and tumour growth in mice, and its inhibition increases effects of gemcitabine; R. Ferro, A. Adamska, R. Lattanzio, I. Mavrommati, C. E. Edling, S. A. Arifin, C. A. Fyffe, G. Sala, L. Sacchetto, G. Chiorino, V. De Laurenzi, M. Piantelli, O. J. Sansom, T. Maffucci & M. Falasca. https://www.nature.com/articles/s41388-018-0390-1   

15: Br J Clin Pharmacol. 2013 Feb;75(2):303-12. doi: 10.1111/j.1365-2125.2012.04298.x; Cannabidiol as potential anticancer drug; Massi P1, Solinas M, Cinquina V, Parolaro D.  https://www.ncbi.nlm.nih.gov/pubmed/22506672

16: CBD, THC, AND CANCER https://www.projectcbd.org/medicine/cbd-thc-and-cancer

17: Cancer Causes Control. 1997 Sep;8(5):722-8; Marijuana use and cancer incidence (California, United States); Sidney S1, Quesenberry CP Jr, Friedman GD, Tekawa IS. https://www.ncbi.nlm.nih.gov/pubmed/9328194?dopt=Abstract

18: Association between cannabis use and the risk of bladder cancer: results from the California Men’s Health Study. Thomas AA1, Wallner LP2, Quinn VP2, Slezak J2, Van Den Eeden SK3, Chien GW4, Jacobsen SJ2; Urology. 2015 Feb;85(2):388-92. doi: 10.1016/j.urology.2014.08.060. Epub 2014 Nov 1. https://www.ncbi.nlm.nih.gov/pubmed/25623697?dopt=Abstract

Related Research:

https://www.cancer.gov/about-cancer/treatment/cam/hp/cannabis-pdq