Is CBD Safe for People With Cancer?

September 22, 2020
ASCO Staff

Cannabidiol, also known as CBD, is one of many chemicals found in the cannabis plant. It has been touted in some online forums as an alternative treatment, and even a cure, for many illnesses, including cancer. And, some people with cancer say that CBD has helped them as a complementary therapy in managing their symptoms and side effects from standard cancer treatment.

Yet there’s very little research around CBD and its use in treating people with cancer. Here’s what to know about what CBD is and what science currently shows about whether it’s safe and effective for people with cancer to use.

What is CBD?

CBD is 1 of the hundreds of chemicals found in the flowering cannabis plant. CBD does not have the psychoactive, or mind-altering, effects of another chemical found in cannabis called tetrahydrocannabinol (THC). THC is the chemical that causes people to experience a “high.” CBD, on the other hand, is being used by some to help ease pain, anxiety, and sleep issues.

CBD comes from cannabis plants called hemp that are specifically grown with high levels of CBD and low levels of THC. Cannabis plants grown with high levels of THC are usually called marijuana. CBD comes from oil that is extracted from the cannabis plant. That oil can then be ingested as a liquid, a capsule, a gummy, or inhaled through vaping. It can also be added as an ingredient in such products as lotions and skin patches.

There is much about CBD that is still unknown. It has largely gone unstudied because, until 2018, it was considered a schedule I drug by the U.S. Drug Enforcement Administration (DEA). A schedule I drug is a drug that has been declared illegal by the DEA because of safety concerns over its potential for abuse and because there is no accepted medical use for it. Then, in September 2018, the DEA updated CBD’s status to become a schedule V drug. Schedule V drugs have a lower potential for abuse and are deemed to have some medical use.

There is currently 1 CBD treatment approved by the U.S. Food and Drug Administration (FDA) called Epidiolex, which is used to treat a rare and severe form of epilepsy in children. There are not currently any FDA-approved CBD medications for treating cancer or side effects of cancer treatments.

Can CBD help people with cancer?

Studies to answer this question are underway. Some scientists are studying whether CBD could relieve some of the side effects of cancer and its treatment, such as pain, insomnia, anxiety, or nausea. Other scientists are studying whether CBD could potentially slow or stop the growth of cancer.

To date, no large-scale studies have shown CBD to have benefits for the treatment of people with cancer. Most studies that have been done evaluating CBD as a cancer treatment were in mice or in human cells in the lab. For instance, there are some studies that have shown that CBD inhibits the growth of cancer cells in mice with lung cancer or colon cancer. Another study showed that CBD, together with THC, killed glioblastoma cancer cells in the lab. However, no studies have been conducted in people with cancer.

There have been some studies that show that CBD, alone or together with THC, may relieve pain, insomnia, or anxiety, but these studies were not specific to people with cancer. While no studies to date have shown that CBD eases these side effects specifically in people with cancer or people receiving cancer treatment, some people with cancer have reported benefits in taking CBD, such as helping with nausea, vomiting, depression, and other side effects. According to ASCO guidelines, your doctor may consider prescribing cannabinoids for chronic pain management if you live in a state where it is legal. However, ASCO guidelines state that there is not enough evidence to support the use of cannabinoids for preventing nausea and vomiting in people with cancer receiving radiation therapy or chemotherapy.

There are 2 synthetic cannabis medications, nabilone (Cesamet) and dronabinol (Marinol or Syndros), that are FDA-approved to treat nausea and vomiting related to chemotherapy. These medications are made in a laboratory.

Is CBD safe for people with cancer?

You may find stories online of people discussing the benefits of CBD as a cancer treatment or as relief for side effects. Please remember that such personal stories, while they may be well-meaning, are shared without scientific study and do not constitute evidence. The safety and efficacy of CBD for people with cancer still has to be proven in large, randomized, controlled clinical trials. 

It is also important to note that some studies have shown that CBD might interfere with how your body processes cancer drugs, called a drug interaction. This might make cancer treatments more toxic or make them less effective. More research is needed on these effects, too. For these reasons, always tell your oncologist if you’re thinking about using CBD before you take it.

You may also be wondering if CBD is legal in your area. Some states allow the sale and possession of cannabis, including CBD and THC, for medical and recreational use. Others have stricter regulations, so state-by-state laws should always be learned before transporting CBD across state lines. Things are more complicated at the federal level. In 2018, the U.S. government recognized that hemp can be grown and manufactured legally as part of the Farm Act. Hemp can be used to make things like rope and clothing, in addition to CBD oil. In other words, hemp is no longer a controlled substance, which means it is not regulated by the government. This means that consumers have to evaluate the safety and quality of CBD products on their own. Some CBD, for example, may have much higher levels of THC than what is labeled.

The bottom line is this: Always talk to your doctor first if you’re thinking about using CBD. Because the research does not yet support the use of CBD in helping people with cancer, it’s important to raise the topic with your doctor before taking it. There are several clinical trials underway studying the use of CBD in cancer care, and you and your oncologist can talk through the possible benefits and risks of you joining a research study to help find answers to some of the questions about CBD, including whether it may reduce side effects or improve quality of life.

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