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Can Medical Marijuana or CBD Help With Prostate Cancer?

Medically Reviewed by Sabrina Felson, MD on June 10, 2022

Medical marijuana is often used to treat conditions such as chronic pain, Parkinson’s disease, multiple sclerosis, epilepsy, and Crohn’s disease. Though it's been studied, there’s not a lot known about whether it can help treat cancer, particularly prostate cancer. Here’s what science does show.

THC vs. CBD: What’s the Difference?

The major components of marijuana are THC (tetrahydrocannabinol) and CBD (cannabidiol). These are known as cannabinoids. THC is what gets you high. CBD does not get you high. Rather, it gives you a mellow, comfortable feeling.

Can Medical Marijuana Treat Prostate Cancer?

There are very well established treatments for prostate cancer that include testosterone blockers, radiation, and surgery as well as other medications. Cannabinoids have been shown to have some activity against prostate cancer in the lab and in mice. But it is not recommended for prostate cancer treatment.

Like other chemicals, these cannabinoids can bind to a part of a cell known as a cell receptor and then influence the cell’s behavior. Cell receptors that bind to cannabinoids fall into two categories:

  • CB1. These receptors are mostly found in the brain and responsible for the potentially pain-relieving properties of marijuana.
  • CB2. These receptors are in the cells of the immune system and blood-forming organs, and may also be in other tissues. When scientists stimulate these receptors with cannabinoids, they’ve been able to kill cancer cells from a variety of human tumors, including brain cancer, lymphomas, and breast cancer.

Research suggests that these cannabinoids help regulate cell growth. They also seem to prevent the growth of cancer cells by making them less likely to survive, grow, spread, and stick to other cancer cells. This means that they may be able to treat many different kinds of cancer, including prostate cancer.

It’s thought that marijuana specifically targets tumor cells but doesn’t really target non-tumor cells. This means that it may be less toxic to the body than other forms of treatment, like chemotherapy.

Research also shows that prostate cancer cells have higher levels of both CB1 and CB2 receptors than normal cells. This means that these cancer cells might be more attracted to cannabinoids than normal cells. Laboratory studies have shown that when these cells are treated with cannabinoids, three things happen:

  1. The cells are more likely to die.
  2. Androgen receptor activity on the prostate cancer cell surface decreases. This is important because prostate cancer is fueled by androgens, which are male hormones.
  3. THC and CBD discourage the formation of tumor blood vessels, which prostate cancer cells need to feed and grow.

One Spanish study found that when cannabinoids were added to three different types of human prostate cancer cells, they slowed the growth of all of them. In fact, the cannabinoids that targeted CB2 were able to kill prostate cancer cells by triggering apoptosis, aka cell death by suicide.

The researchers then transplanted one type of human prostate cancer cell, an aggressive form of cancer known as PC-3, into mice. They divided the mice into three groups: one treated with salt water, one with a cannabinoid, and the third with the same cannabinoid plus a chemical that blocked its effects on CB2. The mice who received the cannabinoid alone experienced a significant reduction in tumor growth compared to the other two groups.

These studies have only looked at prostate cancer cells grown in laboratories or in mice. There are no studies looking at how cannabinoids work in humans, so we don't know if they would work the same way in people. It’s also unclear exactly how cannabinoids prevent prostate cancer cells from getting bigger or dividing.

Can I Use Medical Marijuana to Relieve Symptoms From Prostate Cancer Treatment?

Research shows that medical marijuana may help with:

  • Cancer-related pain. It can help with severe pain, especially if it’s used with opioids. The combination may decrease pain signals in the brain as well as inflammation.
  • Neuropathy. This is a feeling of weakness, numbness, tingling, or burning in the hands or feet due to nerve damage. It’s a common side effect of chemotherapy. Animal studies show that cannabinoids can help relieve some of the symptoms, but human studies are mixed.
  • Nausea and vomiting. Dronabinol and nabilone are synthetic cannabinoids the FDA approved for the treatment of chemotherapy-induced nausea and vomiting. There isn’t research on other forms of marijuana such as smoking, vaping, or CBD oil.
  • Weight loss. Some research shows that THC may help ramp up appetite and slow down weight loss in people with advanced cancer.

Is It Safe to Use Medical Marijuana or CBD Oil With Prostate Cancer?

There are some risks. These include:

  • Loss of control over movement, disorientation, and feelings of anxiety or paranoia.
  • Smoking marijuana carries health risks since it contains many of the same substances found in tobacco smoke.
  • Unpredictability. Marijuana plants come in different strains with different levels of active compounds. This makes it harder to predict how you’ll respond to it.

How Can You Get CBD and Medical Marijuana?

You may also have heard of CBD oil. It’s sold everywhere from your grocery store to vitamin shops. It doesn’t contain THC, the ingredient in marijuana that gets you high. CBD is usually sold as an oil, but you can also find it as an extract, a vaporized liquid, edibles like gummies, in foods, in drinks, and in beauty products. Remember, CBD is not regulated by the FDA, so it’s also hard to know how much CBD you’re getting. One study of 84 CBD products found that more than a quarter contained more CBD than was on the label, and some products even contained THC.

The only medical marijuana product approved by the FDA is a prescription oil called Epidiolex to treat epilepsy. There’s no research to suggest it can treat prostate cancer or relieve cancer treatment-related symptoms. It also may cause side effects like:

  • Dry mouth
  • Diarrhea
  • Loss of appetite
  • Fatigue

It may also interact with other medications you take, like blood thinners. Talk to your doctor to make sure you don’t have any medical conditions that make using it unsafe.

If you’re considering using medical marijuana, check your state regulations. If it’s legal, you should be able to purchase it at a medical dispensary.

Show Sources

SOURCES:

Harvard Health Publishing: “Pot for the Prostate,” “CBD Products Are Everywhere, but Do They Work?”

International Journal of Molecular Sciences: “Cannabinoids and Prostate Cancer: A Systematic Review of Animal Studies.”

British Journal of Pharmacology: “Non-THC Cannabinoids Inhibit Prostate Carcinoma Grown in Vitro and in Vivo: Pro-apoptotic Effects and Underlying Mechanisms.”

British Journal of Cancer: “Inhibition of Human Tumor Prostate PC-3 Cell Growth by Cannabinoids R(+)-Methanandamide and JWH-015: Involvement of CB2.”

American Cancer Society: “Marijuana and Cancer.”

Mayo Clinic: “What Are the Benefits of CBD – and Is it Safe to Use?”

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