One of the earliest studies to examine cannabinoids against breast cancer was in 2010, when Spanish researchers showed THC could combat the HER2+ type (also known as ErbB2). In animals, THC caused cell death (known as apoptosis), reduced the growth of blood vessels to tumors, and decreased spread to lungs. In the chart here, THC was compared with the control group as well a synthetic cannabinoid called JWH-133, which activates the CB2 cannabinoid receptor in a similar way as THC. As demonstrated, mice in both cannabinoid groups had significantly smaller tumor volume. Also notably, whereas 41% of the control group had 4 or more tumors, 0% of cannabinoid-treated animals had that many.
 

The other major cannabinoid, CBD, has also demonstrates activity against breast cancer cells, with a 2011 study indicating it could induce apoptosis in 4 different cell lines, two being estrogen receptor-positive and the others being estrogen receptor-negative. In agreement with other studies, the experiments here pointed to the dose-dependent nature of CBD, with higher doses leading to more cancer cell death.

Another important CBD study was conducted in 2011 by Dr. Sean McAllister of California Pacific Medical Center, where he demonstrated CBD could reduce tumor volume in animals. Part of CBD’s mechanism was downregulating a gene called ID-1, which is involved in tumor growth. As the charts demonstrate, CBD treatment resulted in lower primary tumor volume and weight, reduced number of lung metastases, and less volume in the metastatic regions.

A particularly extensive study was carried out in 2018 by noted researchers Cristina Sanchez and Manuel Guzman’s team in Spain. The goal was to determine if a whole-plant cannabis extract, known as the cannabis drug preparation (CDP), was superior to isolated cannabinoids. The role of terpenes were also examined, as well as which types of breast cancer the cannabinoids were effective against. The main findings were:

• THC and the CDP effectively reduced viability, or number of living cells, of three breast cancer types – ER+/PR+ (T47D cells), HER2+ (HCC1954), and Triple-negative (MDA-MB-231 and SUM159) cells

• The top 5 terpenes in the CDP were not responsible for the extracts’ enhanced efficacy, pointing to the importance of lesser terpenes, other cannabinoids, or other compounds entirely

• The CDP worked by itself and synergized with various chemotherapeutic agents in three different animal experiments

Interestingly, for the ER+/PR+ and HER2+ cells, the CDP was superior to THC at each dose. However, for the triple-negative cells, the highest doses tested of THC and the CDP had essentially equivalent efficacy. More importantly, the animal studies all showed the CDP was vastly superior to THC alone, and that it generally worked together with chemotherapy to enhance efficacy.

Each mouse study conducted was similar, with an inactive vehicle (white), THC alone (green), the CDP alone (blue), a chemotherapy drug (orange), and the chemotherapy drug combined with the CDP (red). This first chart is for ER+/PR+ generated tumors, and the drug used was tamoxifen. In this case, THC was little more effective than the vehicle, while the CDP was essentially equivalent to tamoxifen. The combination of both was most effective.

The HER2+ mouse study was quite similar, although in this case, the CDP, chemotherapy, and combination efficacies were all very similar. Again, THC alone didn’t do much.

Finally, with the triple-negative mouse study, the chemotherapy alone or chemotherapy + CDP combination was significantly better than the CDP alone.

While results can’t be directly extrapolated to humans, this and other evidence strongly favors the superiority of whole-plant cannabis extracts over isolates.

Several patients have reported experiencing anticancer effects from high doses of cannabinoids. Kat Kytle was diagnosed with Stage IV metastatic triple-negative breast cancer around August 2014, with a prognosis of 18 months to 2 years given the cancer’s extent. She declined chemotherapy and used CBD and THC in numerous forms, including topically, infused oils, and a suppository extract. These treatments alone controlled the cancer for a time. It is unclear if Kate stopped using cannabis at some point, but in any case, she was then diagnosed with HER2+ breast cancer in July 2015. At this point, antibody therapy drugs were added to her protocol, and the tumors were nearly eliminated.
 

Tammy Levent is a Florida resident whose cancer battle was covered by a local affiliate of NBC. She was diagnosed with breast cancer in May 2015, and after a lumpectomy removed some of the cancer, she refused further conventional treatment. She then began using apparently THC-rich extract, and in 2016 was cancer free. Lisa Genovese, a nurse on Tammy’s medical team, stated “When I looked at Tammy’s blood work the tumor markers were all zero – and I couldn’t explain it.” Her physician, Dr. Eduardo Palanca, voiced support for more study into the anticancer effects of cannabis, and noted that existing preclinical research already supports THC’s potential.
 

At the 11th National Clinical Conference on Cannabis Therapeutics in May 2017, Dr. Sean McAllister, who conducted the CBD/ID-1 gene study mentioned earlier in this video, discussed his research and shared a fascinating patient case that had been sent to him. The patient used THC and CBD alongside chemotherapy to achieve dramatic reduction of metastatic breast cancer in just 4 months. As the images show, the regression is quite striking and was apparently unexpected with chemotherapy alone. As of this video’s production it is now 2025, and I am less than a week away from attending the 16th incarnation of this same conference.
 

Lin Coxon, a resident of Derbyshire, England, was diagnosed with breast cancer on June 28, 2017. She had a 33mm breast tumor and metastasis to lymph nodes. While awaiting chemotherapy, scheduled in August, she began taking CBD oil to see it would help. By July 24, she could no longer feel the tumor, leading her to get another scan. This revealed the tumor had shrunk to 11mm, and the lymph node metastasis had also decreased tremendously. She then deferred chemotherapy, and using just CBD, beat back the cancer.
In 2020, a smaller amount of cancer returned. Lin tried chemotherapy this time, but couldn’t tolerate it and barely used any. She also had surgery, where a small 1mm nodule of cancer was removed from her breast, along with 5 lymph nodes, of which only 1 was cancerous. Overall, these treatments combined with CBD oil beat the cancer yet again, and as of 2022 Lin was completely cancer free.
 

A report from the Oklahoma station News9 shared Rhonda Gossett’s story of fighting cancer with conventional therapies and cannabis. She initially used just conventional therapies and surgery for metastatic breast cancer, which were successful and kept it at bay for several years. After it returned more aggressively, and conventional therapies were ineffective, Rhonda was told nothing more could be done. At this point, she went to Colorado to use THC oil. Rhonda said she started feeling better soon after starting it, and within a few weeks, scans were showing reductions in her brain metastases. The therapy successfully eliminated the cancer, apparently on its own, within 2 years.
 

Sharon Letts, an accomplished cannabis journalist, was diagnosed with lobular carcinoma breast cancer in 2012. She started on THC extract shortly after diagnosis, which quickly led to symptomatic relief including better sleep. After two and a half months, Sharon was cancer free, having not used any surgery, chemotherapy, or radiation. As of 2025, she is still doing very well. Sharon has had quite a remarkable life, and the picture here shows her with actor and current cannabis farmer Jim Belushi.
 

As the science and human cases demonstrate, cannabis shows immense potential for treating breast cancer. Patients deserve access to cannabis medicines now, and research is more than warranted to prove efficacy at the scale needed to make cannabis a formal anticancer treatment.

The post How Cannabinoids May Help Treat Breast Cancer | Research and Human Cases | Cannabis For Cancer appeared first on The Cannabis for Cancer Declaration.

A 2010 study by German researchers showed that CBD could reduce invasion of both cervical cancer and lung cancer cell lines. The anti-invasive effects were mediated by the cannabinoid receptors CB1 and CB2, as well as another receptor called TRPV1. Since invasion and subsequent metastasis is usually the most dangerous element of cancer development, this property of CBD is quite important.

In addition to inhibiting invasion, research also shows CBD can directly kill cervical cancer cells. A 2016 study by researchers with North-west University in South Africa showed CBD induced a form of programmed cell death called apoptosis. This was also a rare instance where CBD alone was more effective than a whole-plant extract, although overall research tends to suggest that in humans, whole extracts with the full range of cannabinoids and terpenes are more effective.

In 2023, researchers with a different South African school, University of Johannesburg, showed that CBD could work together with a conventional treatment called photodynamic therapy to cause apoptosis in cervical cancer cells. After treating cells with both therapies, only 13% remained viable, with 7% in early apoptosis and 64% in a late stage of the process. In addition to cell death, researchers stated the combined treatment could limit cervical cancer spread.

THC has also been shown to reduce invasion of cervical cancer, with a 2008 study finding that this cannabinoid along with a stable version of the endocannabinoid anandamide decreased cell invasion.

As the previous study indicated, our own endocannabinoids appear to play a role in cervical cancer suppression. This is supported by a 2004 study from the University Hospital in Switzerland, where anandamide induced apoptosis in three different types of cervical cancer cells. In the graph here, the top line with square boxes are healthy cells, and the other three lines are cancer cells. The fact that anandamide is effective makes it at least a little more likely that plant-derived cannabinoids would work in humans.

A woman named Shona Leigh had her story shared on the Australian news website The Courier Mail. She was diagnosed with Stage II cervical cancer in October 2013, and decided to try apparently THC-rich cannabis extract as the only treatment. Shona monitored her progress every six weeks, and by September 2014 had clean test results. She then ceased cannabis use, but four months later, large lumps appeared in her breast. It’s unclear whether this was cancer or not; however, Shona re-started using a cannabis-infused coconut oil, and within 2 weeks, the lumps were gone.

More extensive research is needed for how cannabinoids can help cervical cancer patients. One day, cannabis may be recommended by physicians alongside conventional cancer treatments as a mainstream integrative option.

The post How Cannabinoids May Help Treat Cervical Cancer | Research and Human Cases | Cannabis For Cancer appeared first on The Cannabis for Cancer Declaration.

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.

The post How Cannabinoids May Help Treat Prostate Cancer | Research and Human Cases | Cannabis For Cancer appeared first on The Cannabis for Cancer Declaration.

Don’t believe cannabis can really fight cancer? Learn why it works here!

Most people readily accept that cannabis can help treat symptoms related to cancer or the side effects of conventional treatments. It is well understood that cannabis improves appetite, reduces nausea and vomiting, mitigates pain, and facilitates sleep. But there is a far greater resistance to the notion that cannabis can produce direct anticancer effects in humans.

This resistance is completely understandable, and frankly, the proper initial reaction to have. It’s bold to claim that anything not FDA-approved can fight cancer. Conventional treatments, like chemotherapy, radiation, surgery, or immunotherapy, have undergone extensive double-blind, placebo-controlled trials to prove their safety and efficacy. In addition to these conventional treatments, many alternative interventions exist, including other herbs, foods, machines, or even spiritually-based treatments. When patients forego FDA-approved approaches for alternative treatments that don’t work, they may die where otherwise they would have survived. Therefore, it’s completely reasonable to be skeptical of anything outside the mainstream. However, I’m here to tell you that cannabis is special, and by the end of this video, you’ll at least agree it deserves to be researched more intensely.

Before starting, I must be clear that it is not advisable for any patient to skip conventional treatment and use cannabis instead. Despite the strength of the evidence, there is no way at this time to know who will respond to cannabis therapy. It’s not perfect and doesn’t work for everyone. Thankfully, evidence suggests cannabis can be safely integrated with conventional treatments, and potentially even make them work better. The only exception is with immunotherapy, where evidence indicates cannabis may impair its effectiveness. In patients who are using immunotherapy, the general consensus is for patients to not use cannabis, or at least use it at the lowest possible doses for symptomatic relief, unless the immunotherapy proves ineffective on its own.

Cannabis is composed of hundreds of compounds, the primary therapeutic ones being cannabinoids, terpenes, and flavonoids. These three classes of compounds have been shown to kill cancer cells in preclinical studies, although the focus of this video is on cannabinoids. The most studied plant cannabinoids, called phytocannabinoids, are tetrahydrocannabinol (THC) and cannabidiol (CBD). Both have been consistently demonstrated to directly kill or inhibit virtually every type of cancer cell they’ve been tested against, including brain, bone, breast, cervical, colorectal, prostate, pancreatic, liver, gastric, ovarian, and skin cancer cells, as well as rarer forms like cholangiocarcinoma, rhabdomyosarcoma, and Kaposi sarcoma.

In many, but not all, of these studies, the cannabinoids have demonstrated selective action, only killing the cancer cells while leaving healthy cells alone.

Beyond cells, many animal models with mice and rats have demonstrated that cannabinoids shrink experimentally-generated tumors, including these examples.

Glioma brain tumors

Bone Cancer/Osteosarcoma

Breast Cancer

Cholangiocarcinoma (i) control, (ii) 15 mg/kg THC, (iii) 30 mg/kg THC, (iv) 20 mg/kg CBN, and (v) 40 mg/kg CBN

Gastric Cancer

Liver Cancer

Lung Cancer

Pancreatic Cancer

and Melanoma

Many people would stop here and consider this all a compelling argument. However, none of this is actually all that impressive in isolation, as lots of natural compounds kill cancer cells, even selectively, and shrink tumors in animals.

The first major point that sets phytocannabinoids apart is the fact that endogenous cannabinoids, produced by all mammals and known as endocannabinoids, also kill or inhibit cancer cells through similar mechanisms as the phytocannabinoids. These endocannabinoids bind with cannabinoid receptors on the surface of cells throughout the entire body to produce physiological effects largely related to the maintenance of homeostasis, or internal balance. CB1 receptors are found primarily in the central nervous system, while CB2 receptors are predominantly in the immune system, but one or both receptor types are found in most major organs. For example, CB1 receptors in the brain help regulate neurotransmission, primarily by inhibiting excessive stimulation of neurons, while CB2 receptors help prevent inflammation from getting out of control.

Many studies demonstrate that THC and CBD kill cancer cells by activating CB1 and/or CB2 receptors, as well as other receptors like TRPV1 and PPAR-gamma. Anandamide has also been shown to kill numerous types of cancer cells in the same ways, primarily via CB1 and TRPV1 activation. Moreso, many types of cancer cells express higher levels of cannabinoid receptors than their healthy counterparts. Researchers have posited that this is a potential self-defense mechanism against cancer development – if a healthy cell becomes cancerous, it expresses more cannabinoid receptors to make itself more susceptible to the effects of anandamide, allowing itself to be killed for the good of the organism. If this is the case, it makes sense that phytocannabinoids would be quite an effective cancer treatment, since they would be tapping into an inherent cancer-defense system we already have. For example, in pancreatic cancer, researchers stated, “Cannabinoid receptors are known to be expressed in pancreatic cells, with a higher expression reported in pancreatic cancer patients. Therefore, pharmacological targeting of the endocannabinoid system might offer therapeutic benefits in pancreatic cancer”.

While clinical trials are limited, one double-blind, placebo-controlled trial with glioblastoma patients found those treated with THC and CBD, along with chemotherapy, had median survival of 21.8 months, compared to 12.1 months in the placebo group that only received chemotherapy. It is unlikely this level of life extension could be achieved only from symptom relief, and anticancer effects probably played some role.

Other preclinical evidence for conditions besides cancer has translated radically well to humans. For example, many studies with cells and animals suggested CBD could reduce seizures, including the one here. By 2017, CBD’s antiseizure effects were formally proven to work in real patients, and the pharmaceutical CBD formula Epidiolex was soon approved by the FDA and placed in Schedule V of the Controlled Substances Act, the least restrictive category. The preclinical studies mainly used chemically-driven seizures, which are far less complex than the genetic defect-associated seizures Epidiolex is prescribed for. Therefore, the preclinical evidence for CBD and epilepsy translated to humans better than the evidence indicated.

This translational success bolsters the case for preclinical cancer effects working in humans as well.

Another reasonable concern is how cannabis could possibly be effective against numerous cancer types. As noted, dozens of preclinical studies with cells and animals show that cannabinoids, not to mention terpenes and flavonoids, kill or inhibit most major cancer types. Different receptors may be targeted in disparate cancer types, including CB1, CB2, TRPV1, TRPM8, PPAR-gamma, and GPR55 receptors. The downstream effects of receptor activation generally relate to chemical signaling pathways that lead to impaired reproduction of cancer cells and cell suicide, known as apoptosis.

Real-world evidence, case studies, and media-reported human evidence are also quite compelling. There are hundreds of public cases reported on news websites, social media groups, and local affiliates of stations like ABC, CBS, NBC, BBC, and Fox. In many of these cases, THC-rich and/or CBD-rich extracts were associated with remissions from terminally-diagnosed cancers, such as Rhonda Gossett [breast cancer], Ray Jennings [squamous cell carcinoma], Cecilia von Harz [kidney cancer], Taylor Rehmeyer [brain cancer], and Joy Smith [ovarian cancer].

Case reports published in journals hosted on PubMed also show evidence of anticancer effects in humans. For example:

A case of basal cell carcinoma from Dr. Franjo Grotenhermen, treated with THC extract as the sole therapy

Lung cancer, treated with only CBD oil as the sole therapy

Squamous cell carcinoma, with reversal of a rapidly-growing tumor once topical administration of THC/CBD oil (THC 5.24% + CBD 8.02%) started.

Leukemia, treated solely with THC-rich extract after conventional therapy failed

Another squamous cell carcinoma, treated solely with CBD oil

The chance that every anticancer response is not at all due to cannabis, despite the unusually supportive scientific and logical evidence, is simply impossible. There is no doubt cannabis can fight cancer in at least some cases. However, as noted in the introduction, cannabis does not work for everyone, conventional therapy should not be skipped, and there is still so much more to learn. It’s also almost certain that some anticancer effects attributed to cannabis really were actually caused by other factors. Nonetheless, current evidence more than justifies global access to cannabis medicine for all cancer patients. We also need more research to determine optimal protocols for different cancer types, as well as the full range of benefits and potential adverse effects.

In summary:

Plant cannabinoids like THC and CBD, along with endocannabinoids like anandamide, kill cancer cells through similar mechanisms

Many cancer cells express higher levels of cannabinoid receptors than healthy counterparts, with researchers suggesting this may make them more susceptible to anticancer effects of endocannabinoids

A double-blind, placebo-controlled trial showed THC and CBD extended the lives of glioblastoma patients, suggesting a direct anticancer effect

Other preclinical evidence with cells and animals, such as CBD treating epilepsy, has translated radically well to humans

Positive reports of cannabis producing anticancer effects in humans have been reported in mainstream and social media for the past 15 years

Positive case reports have been published in peer-reviewed journals demonstrating direct anticancer effects

It is imperative that more people learn of the uniquely strong support for cannabis as a cancer treatment, so please share this video with anyone you can. If you want to see more, dozens of scientific articles and over 200 human cases are summarized at FreeCannabisCancerBook.com. The evidence speaks for itself.

To help raise awareness, please consider purchasing and reviewing the equivalent Amazon version here.

The post Cannabis Fights Cancer! The Surprisingly Strong Preclinical, Human, and Logical Evidence appeared first on The Cannabis for Cancer Declaration.