Marijuana and Cancer
Marijuana is the name given to the dried buds and leaves of varieties of the Cannabis sativa plant, which can grow wild in warm and tropical climates throughout the world and be cultivated commercially. It goes by many names, including pot, grass, cannabis, weed, hemp, hash, marihuana, ganja, and dozens of others.
Marijuana has been used in herbal remedies for centuries. Scientists have identified many biologically active components in marijuana. These are called cannabinoids. The two best studied components are the chemicals delta-9-tetrahydrocannabinol (often referred to as THC), and cannabidiol (CBD). Other cannabinoids are being studied.
At this time, the US Drug Enforcement Administration (DEA) lists marijuana and its cannabinoids as Schedule I controlled substances. This means that they cannot legally be prescribed, possessed, or sold under federal law. Whole or crude marijuana (including marijuana oil or hemp oil) is not approved by the US Food and Drug Administration (FDA) for any medical use. But the use of marijuana to treat some medical conditions is legal under state laws in many states.
Dronabinol, a pharmaceutical form of THC, and a man-made cannabinoid drug called nabilone are approved by the FDA to treat some conditions.
Different compounds in marijuana have different actions in the human body. For example, delta-9-tetrahydrocannabinol (THC) seems to cause the “high” reported by marijuana users, and also can help relieve pain and nausea, reduce inflammation, and can act as an antioxidant. Cannabidiol (CBD) can help treat seizures, can reduce anxiety and paranoia, and can counteract the “high” caused by THC.
Different cultivars (strains or types) and even different crops of marijuana plants can have varying amounts of these and other active compounds. This means that marijuana can have different effects based on the strain used.
The effects of marijuana also vary depending on how marijuana compounds enter the body. The most common ways to use marijuana are in food (edible marijuana) and by smoking or vaping it (inhaled marijuana):
- Edible marijuana: When taken by mouth, such as when it’s used in cooking oils, drinks (beer, tea, vodka, soda), baked goods (biscuits, brownies, cookies), and candy, the THC is absorbed poorly and can take hours to be absorbed. Once it’s absorbed, it’s processed by the liver, which produces a second psychoactive compound (a substance that acts on the brain and changes mood or consciousness) that affects the brain differently than THC. It’s important to know that the amount of THC in foods that have had marijuana added to them is often unknown and getting too much THC might cause symptoms of overdose.
- Inhaled marijuana: When marijuana is smoked or vaporized, THC enters the bloodstream and goes to the brain quickly. The second psychoactive compound is produced in small amounts, and so has less effect. The effects of inhaled marijuana fade faster than marijuana taken by mouth.
How can marijuana affect symptoms of cancer?
A number of small studies of smoked marijuana found that it can be helpful in treating nausea and vomiting from cancer chemotherapy.
A few studies have found that inhaled (smoked or vaporized) marijuana can be helpful treatment of neuropathic pain (pain caused by damaged nerves).
Smoked marijuana has also helped improve food intake in HIV patients in studies.
There are no studies in people of the effects of marijuana oil or hemp oil.
Studies have long shown that people who took marijuana extracts in clinical trials tended to need less pain medicine.
More recently, scientists reported that THC and other cannabinoids such as CBD slow growth and/or cause death in certain types of cancer cells growing in lab dishes. Some animal studies also suggest certain cannabinoids may slow growth and reduce spread of some forms of cancer.
There have been some early clinical trials of cannabinoids in treating cancer in humans and more studies are planned. While the studies so far have shown that cannabinoids can be safe in treating cancer, they do not show that they help control or cure the disease.
Relying on marijuana alone as treatment while avoiding or delaying conventional medical care for cancer may have serious health consequences.
Possible harms of marijuana
Marijuana can also pose some harms to users. While the most common effect of marijuana is a feeling of euphoria (“high”), it also can lower the user’s control over movement, cause disorientation, and sometimes cause unpleasant thoughts or feelings of anxiety and paranoia.
Smoked marijuana delivers THC and other cannabinoids to the body, but it also delivers harmful substances to users and those close by, including many of the same substances found in tobacco smoke.
Because marijuana plants come in different strains with different levels of active compounds, it can make each user’s experience very hard to predict. The effects can also differ based on how deeply and for how long the user inhales. Likewise, the effects of ingesting marijuana orally can vary between people. Also, some chronic users can develop an unhealthy dependence on marijuana.
There are 2 chemically pure drugs based on marijuana compounds that have been approved in the US for medical use.
- Dronabinol (Marinol®) is a gelatin capsule containing delta-9-tetrahydrocannabinol (THC) that’s approved by the US Food and Drug Administration (FDA) to treat nausea and vomiting caused by cancer chemotherapy as well as weight loss and poor appetite in patients with AIDS.
- Nabilone (Cesamet®) is a synthetic cannabinoid that acts much like THC. It can be taken by mouth to treat nausea and vomiting caused by cancer chemotherapy when other drugs have not worked.
Nabiximols is a cannabinoid drug still under study in the US. It’s a mouth spray made up of a whole-plant extract with THC and cannabidiol (CBD) in an almost one to one mix. It’s available in Canada and parts of Europe to treat pain linked to cancer, as well as muscle spasms and pain from multiple sclerosis (MS). It’s not approved in the US at this time, but it’s being tested in clinical trials to see if it can help a number of conditions.
How can cannabinoid drugs affect symptoms of cancer?
Based on a number of studies, dronabinol can be helpful for reducing nausea and vomiting linked to chemotherapy.
Dronabinol has also been found to help improve food intake and prevent weight loss in patients with HIV. In studies of cancer patients, though, it wasn’t better than placebo or another drug (megestrol acetate).
Nabiximols has shown promise for helping people with cancer pain that’s unrelieved by strong pain medicines, but it hasn’t been found to be helpful in every study done. Research is still being done on this drug.
Side effects of cannabinoid drugs
Like many other drugs, the prescription cannabinoids, dronabinol and nabilone, can cause side effects and complications.
Some people have trouble with increased heart rate, decreased blood pressure (especially when standing up), dizziness or lightheadedness, and fainting. These drugs can cause drowsiness as well as mood changes or a feeling of being “high” that some people find uncomfortable. They can also worsen depression, mania, or other mental illness. Some patients taking nabilone in studies reported hallucinations. The drugs may increase some effects of sedatives, sleeping pills, or alcohol, such as sleepiness and poor coordination. Patients have also reported problems with dry mouth and trouble with recent memory.
Older patients may have more problems with side effects and are usually started on lower doses.
People who have had emotional illnesses, paranoia, or hallucinations may find their symptoms are worse when taking cannabinoid drugs.
Talk to your doctor about what you should expect when taking one of these drugs. It’s a good idea to have someone with you when you first start taking one of these drugs and after any dose changes.
What does the American Cancer Society say about the use of marijuana in people with cancer?
The American Cancer Society supports the need for more scientific research on cannabinoids for cancer patients, and recognizes the need for better and more effective therapies that can overcome the often debilitating side effects of cancer and its treatment. The Society also believes that the classification of marijuana as a Schedule I controlled substance by the US Drug Enforcement Administration imposes numerous conditions on researchers and deters scientific study of cannabinoids. Federal officials should examine options consistent with federal law for enabling more scientific study on marijuana.
Medical decisions about pain and symptom management should be made between the patient and his or her doctor, balancing evidence of benefit and harm to the patient, the patient’s preferences and values, and any laws and regulations that may apply.
The American Cancer Society Cancer Action Network (ACS CAN), the Society’s advocacy affiliate, has not taken a position on legalization of marijuana for medical purposes because of the need for more scientific research on marijuana’s potential benefits and harms. However, ACS CAN opposes the smoking or vaping of marijuana and other cannabinoids in public places because the carcinogens in marijuana smoke pose numerous health hazards to the patient and others in the patient’s presence.
Learn how marijuana and drugs derived from the marijuana plant can affect cancer-related symptoms.
Cbd oil for cancer
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.
Cannabidiol (CBD) has become a buzzword within the cancer community. But while some people with cancer have found CBD to be helpful in managing side effects, research does not yet support CBD’s use for cancer treatment. Here, find out what CBD is, how it is being studied in people with cancer, and whether it is safe, effective, and legal.