Medical Cannabis and cancer
It’s important for cancer patients to understand that Cannabis is not a simple “cure” for cancer, and ideally, should be used in conjunction with radiation, chemotherapy, surgery, medication, and other treatments as directed by your oncologist.
Studies have demonstrated that marijuana’s active ingredients, which are called “cannabinoids,” such as THC (Tetrahydrocannabinol), appear to have cancer-fighting properties with regard to certain types of tumours. Research published in 2009 in the Journal of Clinical Investigation noted that “THC, the main active component of marijuana, induces human glioma cell death.” Glioma refers to tumours arising from glia or glial cells of the brain.
The same effect was also noted by an earlier study, published in 2001 in the Journal of Molecular Medicine. This study found that “cannabinoids induce apoptosis,” or cell death, “of glioma cells in culture and regression of malignant gliomas in vivo.” As the same study further noted, “Breast and prostate cancer cells are also sensitive to cannabinoid-induced anti-proliferation.”
The bottom line is that, though marijuana is not necessarily a cure for cancer, THC and other cannabinoids do appear to have demonstrable cancer-fighting properties.

How Does Marijuana Help Cancer Effects?
In addition to fighting cancer directly as per the above, marijuana can also help to alleviate the effects of cancer, as well as the effects of associated radiation, surgery, and chemotherapy. To summarize, research has shown that Cannabis can rapidly and effectively reduce or counter:
Anxiety
Depression
Lack of Appetite
Insomnia
Nausea
Pain
In most cases, patients experience mild side-effects which have a very low chance of causing long-term harm. For most people, the worst aspects of Cannabis use are temporary dry mouth and increased drowsiness.

Medical Marijuana to Relieve Pain and Nausea during Chemotherapy
The reason Cannabis relieves pain and nausea, reduces depression and anxiety, and improves appetite and sleep quality is found within your own body: specifically, within the little-known endocannabinoid system (ECS). The endocannabinoid system is crucial for regulating mental and physical functions, including mood, appetite, and pain perception.
Cannabis contains more than a hundred distinct chemical compounds, the best-known of which is THC. Your body also contains its own natural cannabinoids, which are known as endocannabinoids because they are produced inside your body (which is what the prefix “endo-” denotes). Examples of endocannabinoids made by your body include Anandamide (AEA) and 2-Arachidonoylglycerol (2-AG).
AEA and other endocannabinoids constantly interact with the CB1 and CB2 receptors that make up your body’s endocannabinoid system. During this process, signals are sent to and from your brain, which affects your appetite, mood, and other functions. When you use Cannabis, THC and other cannabinoids interact with these same receptors, thereby altering your mood, increasing your appetite, and changing the way you perceive pain or discomfort.