Learn more about medical marijuana

Cancer Side Effects and Medical Marijuana: What’s the Connection?

If you or a loved one has cancer, you’re probably considering every option for easing side effects of treatments like chemotherapy and radiation. Many ask about the connection between cancer side effects and medical marijuana.

While this plant has a reputation as a recreational drug, a growing body of research suggests that it may have potential health benefits, too. Here’s what to keep in mind.

Learn more about integrative oncology on the UPMC Hillman Cancer Center website.  

Medical Marijuana and Cancer Care

There are three recognized species of marijuana:

  • Sativa
  • Indica
  • Ruderalis

The different strains appear to have varying physiological and psychological effects. The plant also contains about a hundred different compounds, called cannabinoids, which appear to activate specific receptors throughout the human body.

The best known of these compounds is delta-9-tetrahydrocannabinol, or THC, which is believed to be responsible for cannabis’s psychoactive effects. Another compound, cannabidiol, is a nonpsychoactive cannabinoid that shows promise: Studies suggest that it helps protect against nerve-related pain, has antiseizure properties, and may inhibit the proliferation of cancer cells.

People with cancer may use cannabis for a variety of symptoms. The most robust evidence is in the areas of appetite, nausea and vomiting, and pain.

Appetite and Marijuana Use

In 1986, the Food and Drug Administration first licensed and approved dronabinol — a prescription drug that contains synthetic THC — to treat nausea and vomiting associated with chemotherapy.

Evidence to support the use of dronabinol, however, is mixed. One clinical trial by Cantonal Hospital in Switzerland looked at an extract of cannabis and dronabinol in 243 people with cancer-related anorexia-cachexia syndrome, and found that neither was better than a placebo pill at affecting appetite.

Another study, published in the Journal of Clinical Oncology, found that of 469 people with advanced cancer who received the drug megestrol acetate, dronabinol, or both, those who took megestrol had significantly greater increases in both weight and appetite. Combining dronabinol with megestrol seemed to offer no additional benefit compared with megestrol alone, suggesting that marijuana and cancer side effects might not always be linked.

Yet other research suggests that smoking real marijuana (rather than taking it as a synthetic medication) may improve appetite.

For instance, one study of six healthy men by Johns Hopkins University School of Medicine in the 1980s found that those who smoked marijuana that contained THC also consumed 40 percent more calories than their peers (hence, the munchies).

Marijuana for Nausea and Vomiting

The National Comprehensive Cancer Network recommends cannabinoids for the treatment of chemotherapy-related nausea and vomiting when conventional measures have failed. This advice is based on numerous studies that show THC is more effective than prescription antinausea drugs.

Marijuana for Pain Management

A growing body of evidence suggests that cannabinoids have pain-relieving effects. Research led by the University of Toronto indicates that they may relieve cancer pain as well as or better than other medicines, but there aren’t enough studies to draw definitive conclusions.

Because government regulations make it challenging for researchers to investigate the health effects of marijuana, the current clinical evidence for cannabis and cancer may not accurately reflect its potential real-life benefits.

RELATED: Coping with Chemo Side Effects

Cancer Treatment and Cannabis

Perhaps the most exciting area of current research involves the anticancer properties of cannabinoids. According to the National Cancer Institute, a number of studies suggest that these compounds can inhibit the growth of skin, uterine, breast, stomach, thyroid, colorectal, pancreatic, brain, and prostate cancer cells.

Unlike most conventional chemotherapy drugs, cannabinoids appear to kill tumor cells without adversely affecting surrounding normal cells. This could be great news for people interested in the link between cannabis and cancer.

Looking at the Big Picture on Medical Marijuana

Pharmaceuticals used for appetite, nausea, and pain, as well as insomnia, neuropathy, and fatigue often produce unwanted side effects. Cannabis may control symptoms with fewer adverse effects.

For many people, having one form of treatment that can target multiple symptoms at once is reason enough to consider cannabis.

It’s worth re-stating: The current clinical evidence for cannabis and cancer is limited, because marijuana has historically been considered illegal.

But many states, including Pennsylvania, are adopting medical marijuana legislation and processes. The use of medical marijuana is largely an uncharted area because many doctors, particularly those who treat cancer, are used to prescribing drugs with specific doses based on well-defined clinical trials.

In order to use medical marijuana, patients will need a recommendation from a doctor with a pre-defined diagnosis and condition. A dispensary will then provide the specific type of marijuana needed.

The Wellness and Integrative Oncology Program at UPMC Hillman Cancer Center

As the process unfolds in Pennsylvania, the Wellness and Integrative Oncology Program at UPMC Hillman Cancer Center (WIOP) is committed to providing patients for whom the benefits of using medicinal marijuana outweigh any potential risks with the clearest and most up to date information.

This includes qualifications, timelines, logistics, and updated research that will evolve from a legal status for medical marijuana.

At the WIOP, our philosophy is to guide patients as collaborative participants in whole-person care. With the exciting potential of cannabis in cancer care, we are poised for this situation with expertise and our patient’s best interest in mind.