Medical Marijuana and Cancer

Marijuana comes from the leaves and buds of the cannabis plant. Its use remains controversial in the United States, with the Drug Enforcement Administration labelling it a Schedule I drug, which means it’s illegal under federal law. But the use of medical marijuana in some form is legal in 36 states, the District of Columbia, Guam, Puerto Rico and U.S. Virgin Islands.

Marijuana and Its Status

With the increasing availability of marijuana in the United States, it is important to understand its legal status and medical uses. The marijuana plant has multiple active ingredients, known as cannabinoids. At this time, two of these can be used for potential therapies. The first is THC (Delta-9-terahydrocannabinol), which produces the “high” feeling associated with marijuana. The other is CBD (cannabidiol), which may be able to treat pain, anxiety, stimulate appetite and affect symptoms such as seizures in some patients.

The use of medical marijuana may involve one or both of these cannabinoids and may be given in pill, cream or other forms. Research into the uses of medical marijuana is ongoing, although the labeling of marijuana as an illegal drug has greatly limited its research possibilities. There are currently 3 FDA-approved cannabinoid medications available in the U.S. Two of them have been specifically indicated for use in cancer patients. More studies are needed to fully understand their potential benefits to improve symptoms and quality of life for individuals living with cancer. Our knowledge will continue to change.

Cancer and Marijuana

A number of studies have shown that medical marijuana may help in managing the following:

Pain. Marijuana may be helpful for the management of cancer-related pain when conventional therapies are ineffective or are causing adverse effects. For patients with severe cancer pain, opioids are still considered the standard of treatment, but simultaneous use of marijuana may decrease pain signals in the brain, with additional anti-inflammatory properties.

Neuropathy. Neuropathy, or nerve damage, is a feeling of weakness, numbness, tingling or burning in the hands and/or feet. It is a common side effect of chemotherapy and other cancer treatments. Studies on animals have demonstrated that cannabinoids can be helpful in relieving some of the symptoms of nerve damage. However, small studies involving patients looking into varied combinations of THC and CBD have returned mixed results.

Nausea and vomiting. Many patients experience nausea and vomiting as a side effect of chemotherapy. Dronabinol and nabilone are synthetic cannabinoids FDA approved for the treatment of chemotherapy-induced nausea and vomiting. Past studies have only looked at the use of oral cannabinoids rather than other forms of marijuana such as smoking, vaping or oral sprays. This is also an area that may need to be researched more.

Appetite and weight loss. Limited studies have demonstrated that THC stimulates appetite and helps to slow down weight loss in patients with advanced cancer. However, it was not considered more effective than conventional treatment.

Still, several states have approved the use of medical marijuana for the treatment of cancer-related anorexia (the medical term for loss of appetite) and/or cachexia (wasting away of the body resulting from severe chronic illness).

Important Notes About Medical Marijuana

Open and honest communication about any symptoms or pain can help your health care team to determine if medical marijuana or FDA-approved cannabinoid medication is a treatment option for you. Registered doctors and nurse practitioners can certify you to receive medical marijuana if they think it can be beneficial and is available in your area.

There are some vital considerations when it comes to marijuana use:

Marijuana legality. Each state has different laws dictating the legality of medical marijuana, including qualifying conditions and dispensing of medical marijuana. Medical marijuana and patient ID cards should not be used or transported out of state, given that the legal status of marijuana varies state to state. For up-to-date state and federal laws, visit https://www.ncsl.org/research/health/state-medical marijuana-laws.aspx.

Danger of smoking marijuana. Smoking marijuana allows active cannabinoids to enter the bloodstream directly through the lungs, but smoking has other health risks, similar to smoking cigarettes. Pills/capsules, edibles, vapes, oils, drops, topical creams or sprays are some of the alternative means of using medical marijuana. Their availability varies state to state.

Other marijuana side effects. Side effects include sleepiness, mood changes, decreased blood pressure and changes in heart rate. This can vary from person to person and should be discussed with your health care team.

Edited by Reggie Saldivar, MD., Supportive Care Service, Memorial Sloan Kettering Cancer Center