How Cannabinoids May Help Treat Prostate Cancer | Research and Human Cases | Cannabis For Cancer
Prostate cancer is the second most common diagnosed type of cancer in men. While it is often slow-growing and not aggressive, this is not always the case, as over 35,000 people in the United States die from prostate cancer each year. Surprisingly, it is the fifth leading cause of death worldwide. Preclinical and human evidence suggests cannabinoids can make a difference.
One of the earliest studies on the anticancer effects of cannabinoids was in 1999, when researchers in Spain showed THC could induce apoptosis, or programmed cell death, in human prostate cancer cells. Interestingly, while THC activates CB1 and CB2 receptors, these were not shown to play a role in THC’s effects.
CBD has also been shown to induce apoptosis in prostate cancer cells. Quite interestingly, unlike THC, one study showed CBD’s ability to kill prostate cancer cells was dependent on interactions with CB1 and CB2 receptors.
A 2013 study by the prolific Italian cannabis researchers Luciano De Petrocellis and Vincenzo Di Marzo tested a wide variety of cannabinoids in two types of prostate cancer cells, androgen receptor-positive and negative. In addition to isolated cannabinoids, researchers tested “botanical drug substances” (BDS), which are whole-plant extracts.
The following charts list the IC50 values of many cannabinoids and extracts. There’s a lot going on in these charts, so some explanations are necessary. IC50 is the quantity required to reduce viability (number of living cells) by 50%, so lower numbers mean greater potency. Columns where the value is >25 means that the maximum concentration tested was not capable of inhibiting viability by 50%. Column A features cells tested with serum, and column B is cells tested without serum, with the latter conditions being more effective because the serum impaired cannabinoid activity.
The key observation is that all cannabinoids and whole-plant extracts tested exerted inhibitory activities against both androgen receptor-positive and negative prostate cancer cells. In most cases, the whole-plant extracts are more potent, but not always. For example, the IC50 value of CBD is lower than the IC50 value of CBD BDS, meaning CBD alone was better. However, for CBC (cannabichromene) and several cannabinoids below, the BDS was more potent. Feel free to pause the video to review these charts further, but overall it’s just good to know that most major cannabinoids inhibit growth of two major types of prostate cancer.
In animals, escalating doses of the whole-plant CBD extract were shown to have greater antitumor effects, with the 100mg/kg dose having virtually equivalent efficacy as 5mg/kg of the chemotherapy drug Taxotere. This is demonstrated by the yellow and green lines below, respectively. This result is also generally in agreement with other studies showing conventional chemotherapy drugs are more potent than cannabinoids, and thus why such high doses of cannabinoids are reportedly needed to achieve anticancer effects.
In 2023, an international team of researchers, including those with the University of Brescia in Italy and University of Portsmouth in the United Kingdom, showed that both CBD and cannabigerol (CBG) could induce apoptosis in in prostate cancer cells, including cells that had become resistant to treatment with the hormone therapy enzalutamide. A 1:1 ratio of both cannabinoids was shown to be an effective treatment in an animal model as well. The chart below shows that at 18 weeks, the percentage of pathological area – essentially, the amount of cancer present – is sharply reduced in the cannabinoid-treated mice compared to untreated mice.
I would now like to describe some real-life cases, including someone I worked with directly – Dennis Hill. His story became quite publicized and was even covered by Al Jazeera. He was diagnosed with prostate cancer, specifically Stage 3 adenocarcinoma, in February 2010. Here’s his original diagnosis document:
Dennis decided he wanted to avoid most conventional treatments, although he did use three injections of Lupron, an androgen antagonist that can slow cancer growth. In concert with that treatment, he ingested high doses of cannabis butter for 3 months before acquiring THC-rich extract, which he took for another 3 months. After this course, tests showed he was cancer free, as indicated by this follow-up report:
Dennis stayed healthy until 2018, when he was diagnosed with lung cancer at the age of 81. He decided he was ready to leave the world, and only used low doses of cannabis for palliative treatment, passing away on March 18, 2019. He was a truly great man, and I feel fortunate I was able to attend one of his meditation classes, where I continue to use the mantra he taught me to this day.
Another positive case was reported in the podcast Cannabis Health Radio. A man named Michael House was diagnosed with Stage IV metastatic prostate cancer, having spread to his pubic bone and lymph nodes. Doctors gave him 20-24 months to live with docetaxel chemotherapy and testosterone suppression. House used these treatments combined with supplements, diet change, and 400mg of CBD per day to eventually fully eliminate the cancer. Both his and Dennis’ cases are testaments to how cannabinoids can be safely integrated with forms of conventional treatment to produce greater-than-expected responses. While more research is needed, it is clear that cannabinoids can be safely integrated with conventional treatments in a responsible manner.
