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Can Cannabis Cause Cancer?

For thousands of years, cannabis has been used in medicines to help treat various forms of illnesses. In ancient China, cannabis was widely used to treat problems of the stomach, eyes, and other illnesses, and there are no ancient texts that tell how cannabis use in patients made the latter sicker.

This is no surprise; what ancient physician would want to tell how he treated someone with cannabis and they died of something they did not originally have? It would likely have cost them their lives. But what about now?Today, with so many methods of testing and researching the potential benefits and long-term side effects of modern drugs, what is the evidence that proves cannabis either does or does not cause cancer?

More Study Is Needed on Cannabis and Cancer

There has not been enough long-term study on the effects of cannabis on cancer cells, and the effects of the smoke on cancer, if it is smoked. Research into the effects of cannabis is relatively new and obviously requires a lot more study before any definitive statements can be made as to whether or not it is dangerous. What is known at this point is that some of the research into cannabis use has shown that the idea of cannabis causing cancer growth in the body is more likely to be fiction than fact. There is not enough evidence yet to claim that cannabis has never and will never cause cancer in humans. What there is are studies that show that it is most likely that cannabis does not "increase' the risk of getting cancer.

Antitumoral Associations Observed in the Treatment of Cancer Patients

Tobacco mainly causes cancer by the deep inhalation of the smoke from the cigarettes. People who smoke cannabis also inhale the smoke deep into their lungs and often hold the smoke in for longer than normal cigarette smokers hold. According to the American Lung Association, marijuana smoke has been shown to contain many of the same toxins and carcinogens as tobacco smoke, while smoking cannabis is considered less dangerous than smoking tobacco. There are some general differences in the habits of cannabis smokers and tobaccos smokers. Tobacco smokers often smoke more often, and over much longer periods than cannabis smokers, and there is a huge lack of data from heavy, prolonged cannabis smokers to show if there are the same ill effects as heavy, prolonged tobacco smokers.

If it is taken on the carcinogens and toxins alone, then it can be assumed that cannabis smoking, at the same rate as a heavy tobacco smoker, could increase the risk of cancer. However, in a large, case-controlled study at the University of California in Los Angeles in 2006, suggested that the association of cancers with marijuana, even with prolonged heavy use, is not strong enough to prove the case of causing cancer. The research, which was funded and run by the National Association of Health, found that there were no positive associations between the use of marijuana and the common lung and upper airways tract cancers. Rather, on the contrary, the studies showed that the use of tetrahydrocannabinol (THC) and other cannabinoids may even inhibit the growth of cancer cells and tumors. The report concluded that there were definite antitumoral associations observed in the treatment of cancer patients with THCs in lung, breast, thyroid, prostate, and brain cancers.

Could Cannabis Be the Final Cure for Cancer?

So, is there a chance that cannabis use could help to make tumors disappear and cancer cells diminish? In a report published in 2014 in the International Journal of Cancer, investigations into the case studies of six different research teams in the United States, the United Kingdom, and New Zealand, were pooled together. The pooled data of more than 2,000 lung cancer patients and over 3,000 controlled case studies showed that there was little evidence to show that there was any increase in the risk of lung cancer with habitual, long-term cannabis smokers. This lends weight to the idea that cannabis does not actually cause cancer, although there is still no definite evidence to say yes or no on that issue.

Around the world, hundreds of scientific research teams are investigating the potential use of cannabinoids in the treatment of cancer and other diseases, as well as the potential for any harm that could result from its use. This research has been brought together under the blanket of the International Cannabinoid Research Society. Since researchers first started looking into the potential cancer-treating properties of cannabinoids in the 1970s, hundreds of scientific papers have been published. Moreover, there have been seminars and supplements on the research around the world, that are fascinating reading for anyone interested in the use of cannabinoids.

Some Positive Effects Are Proven

It has been proven through many detailed experiments that various cannabinoid have a wide range of effects on cancer cells under laboratory conditions, such as:

  • Triggering cell death, through a mechanism called apoptosis
  • Stopping cells from dividing
  • Preventing new blood vessels from growing into tumors
  • Reducing the chances of cancer cells spreading through the body, by stopping cells from moving or invading neighboring tissue
  • Speeding up the cell's internal ‘waste disposal machine' – a process known as autophagy – which can lead to cell death

These positive effects appear to be caused by the cannabinoids locking onto the CB1 and CB2 cannabinoid receptors. It would also appear, from the lab tests, that cannabinoids can also exert positive effects on cells that do not have cannabinoid receptors, although the "why" is not yet clear. Until now, the best results in the labs, using l;ab-grown and animal cells, have come from using a combination of THC that has been highly purified and cannabidiol, or CBD. Cannabidiol is found in cannabis plants and is a cannabinoid that counteracts the psychotropic effects of the THCs. Synthetic cannabinoids, such as the molecule JWH-133, have also been shown to provide similar results.

Many Questions Remained Unanswered

However, it is not all gravy here. Some studies have also shown that, while the cannabinoids have had effective results in treating cancer cells, they have also been shown to harm crucial blood vessel cells, when the THC was used in a high enough dose to kill the cancer cells. While this may have some beneficial effects in preventing blood cells from growing into tumors, the damage could be potentially fatal. Moreover, under some circumstances, the use of the cannabinoids has actually promoted the growth of the lab-generated cancer cells, or have had varying effects depending on the dosage and the levels of cannabinoid receptors in the cancer cells.

Other evidence suggests that the activation of the CB2 cannabinoid receptors can interfere with the body's immune system, preventing it from detecting and removing tumor cells, while the use of certain synthetic cannabinoids can actually enhance the immune system in defending against cancer. It is also shown that, under certain conditions, cancer cells can develop an immunity to the cannabinoids, and start growing again. This, however, can be prevented by blocking the ALK molecular pathways in the cells

There are still thousands of unanswered questions about the potential for using cannabis and cannabinoids in the treatment of cancer. And while research is constantly going on around the world, there is still not enough evidence to show that the treatments that worked on lab-grown and animal cancer cells will also work in humans.

It is also unclear as to which type of cannabinoid will have the most effect on cancer cells in humans, or which types of cancer will respond positively to them. There have been a lot of interesting results from experiments and studies that show potential in the prostate, breast, lung cancer, skin, bone and pancreatic cancers, glioma brain tumors and lymphoma. It is generally acknowledged that different cannabinoids have different effects on different forms of cancer, so the research is still a very long way from producing a universal treatment for cancer. Science is still a long way from producing a drug based on cannabinoids that can cure cancer in patients, and from producing preventive drugs to reduce the risk of getting cancer in the future.

Cannabis Does Help in Pain and Nausea Relief

What has been proven is that cannabis and cannabinoids can have a positive effect on the effects of chemotherapy, in reducing nausea and vomiting caused by the treatment. It has also been proven that it can have a palliative use in relieving pain and some symptoms of cancer pain. One problem, though, is still the dosage. When taking it by inhalation or in tea or foods, the dosage is hugely varied, and it can make it difficult to monitor what is the optimal dosage for the treatment of pain and nausea. This has prompted researchers to turn to alternative dosing methods, like mouth sprays, which can deliver a regulated dose that could be more reliable than inhalation and ingestion.

Only time will tell if cannabis and cannabinoids will be the final cure for the worst disease in human history, after the bubonic plague. Time, and study, and more experiments. And those are constantly going on, to try and discover whether cannabis is going to be the way forward in treating cancer, or if it is just the first step in getting to the final stage, where cancer will finally be a thing of the past. Let's see…

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