Tetrahydrocannabinol, or THC, the active compound in marijuana, has been found to be able to reduce tumor growth in various forms of lung cancer by as much as 50%. Additionally, the Harvard University study demonstrated that it also slowed down the cancer’s ability to spread. As such, further research is now being conducted to determine whether it could use as a targeted type of lung cancer treatment.

The active ingredient in marijuana cuts tumor growth in common lung cancer in half and significantly reduces the ability of the cancer to spread, say researchers at Harvard University who tested the chemical in both lab and mouse studies.


It is not known yet how THC is able to inhibit the growth of tumors. However, it is believed that it may activate certain molecules that stop the cell cycle from reproducing. At present, researchers suggest that THC also interferes with vascularization and angiogenesis, two systems that promote the growth of cancers.

Research on Marijuana and Cancer Development

Interestingly, a different piece of research published in 2006 found that there is no increased risk of developing head-and-neck malignancies or lung cancers, even when it is smoked by heavy users. The more tobacco that is smoked, the greater the risk of developing cancer of the neck, head, or lungs. However, if people smoked more marijuana, this risk did not increase, even compared with full non-smokers. In fact, the research looked at very heavy marijuana smokers, who had smoked in excess of 22,000 joints over the course of their lifetime, and the results were consistent.

This came as a significant surprise, as it was expected that those who smoked more would also be at higher risk of developing cancers. Marijuana is known to contain as many, if not more, co-carcinogens and carcinogens as what there are in tobacco. However, there was still no increased risk of developing any cancer by smoking marijuana.

Because the cancer risk ratio of marijuana use has now been determined to be below 1.0, it has been conclusively proven that there is no risk of respiratory cancers associated with smoking marijuana. This is in stark contrast to smoking tobacco, which increases the risk of developing certain types of cancers by 21.

Research suggests that the THC encourages apoptosis. This is a programmed cell death. It means, therefore, that the cells will die before they are able to go through a malignant transformation and become cancerous.

Marijuana has been studied for several decades now, and the fact that it does not increase the risk of developing smoking related cancers continues to come as a surprise. In fact, when the latest studies were conducted, the hypothesis was that there would be a positive correlation between lung cancer and marijuana, and that this association would be stronger the more marijuana someone smoked. Instead, there was no association found and there is even the suggestion that it has a protective effect.

In April 2009, these findings were once again confirmed in a study by the Vancouver Burden of Obstructive Lung Disease Research Group. They found that if people smoked both tobacco and marijuana together, they were at greater risk of developing COPD. However, smoking marijuana on its own did not increase this risk.

Research on Marijuana and Cancer Treatment

There have been numerous stories of people who believe they have controlled or even cured lung cancer through marijuana use. While medicinally available to help people cope with pain, researchers continue to be reluctant to say that the plant could actually provide a cure. There is even a report of a stage IV cancer patient in Australia who miraculously recovered, and who attributes this to smoking cannabis. The woman in question was declared terminal and given just weeks to live. Her scan pictures show the extent of the cancer. She decided to smoke marijuana for the remainder of her life, mainly in order to relieve the symptoms. Shortly thereafter, she started to notice improvement in her overall quality of life. Nine months after her last CT scan that showed how far the cancer had spread, she had another CT scan completed that showed she was now free of the disease.

Researchers are looking into her amazing story and are trying to determine which factors were of influence in this. It is undeniable that the lady had cancer, and it is undeniable that she is now cured. How this happened, however, is unclear.

Marijuana and Mesothelioma

As with the lung cancer stories, there have been a number of people who have stated that their mesothelioma has been healed, thanks to marijuana. These stories are now so frequent that the U.S Department of Veterans Affairs no longer cuts benefits for veterans who treat themselves with marijuana. Naturally, there are some significant limitations on how and where the marijuana can be used, but it does demonstrate an acknowledgement that marijuana does something positive to those who suffer from mesothelioma.

Mesothelioma is a very rare cancer, but U.S. Navy veterans are most likely to be affected by the disease, because asbestos was present in their working environment for a very long period of time. Asbestos was found in military vehicles and equipment, and even in cigarettes provided to service personal, which were the Kent cigarettes. As a result, a significant amount of attention is paid to the effects of asbestos on veterans and on how their quality of life can be improved. These men and women gave their lives for the safety of this country, and the fact that they may be struck down by a terminal illness caused by their working environment half a century after it happened means that the medical world is highly focused on finding a solution for these very people. Whether or not this is marijuana remains to be seen, but it is clear that people, if nothing else, enjoy a greater quality of life in their final few days, and this is something that should be supported and applauded.

With laws on the use of marijuana relaxing across many states, scientists may soon start to develop significant clinical trials to better determine the various links between marijuana and cancer, including lung cancer and mesothelioma. Because there is currently no cure for mesothelioma, and most people aren’t diagnosed until the disease has progressed to terminal stage, patients are often asked to take part in clinical trials to help improve outcomes for future sufferers. This may soon include marijuana trials, although no current research studies have been listed in the usual locations.