CBD and THC in Cancer Symptom Management and Tumor Growth Inhibition

Currently, many U.S. states and several European countries allow the use of medical marijuana as an alternative or complementary method for managing cancer symptoms or the side effects of chemotherapy. In addition to the fact that cannabinoids found in the plant (specifically THC and CBD) can suppress pain, nausea, and physical discomfort in patients, some private studies and practical applications have shown that these substances may also inhibit the growth of cancer cells. Some research even notes that, when combined with radiation or chemotherapy, cannabinoids can destroy diseased cells without negatively affecting healthy tissues or the body’s biological processes.

Although most published and ongoing studies use isolated forms of these cannabinoids, the combination of THC and CBD has shown the greatest effectiveness due to the synergistic interaction between the compounds. Dr. Sean McAllister, in a recently published study, reported that even at low concentrations, a mixture of CBD and THC demonstrated a noticeable ability to slow the growth of cancer cell cultures. Overall, the combined effect of these substances was several times greater than their individual effects, both in strength and duration.

Additionally, Dr. McAllister’s colleagues note that the greatest effect in cancer therapy is seen when cannabis oils are used together with other treatment methods, particularly chemotherapy and radiation therapy.

Research into the chemical mechanisms of cannabinoid interaction has shown that CBD acts as a neuromodulator for the overall effect of THC on the body, which has a more pronounced psychoactive impact. Thus, when used together, one substance balances the effect of the other, enhancing the duration and strength of its therapeutic impact, slowing the breakdown of active compounds in the body, and significantly reducing the risk of negative side effects from THC, such as nervousness, panic, or nausea.

Currently, it is legal to purchase medications containing isolated CBD extract in the pharmaceutical markets of the European Union and the United States (with a proper prescription from a physician and government approval according to local regulations). As an exception containing THC, the popular product Sativex by GW Pharmaceuticals can be cited. This medication, used in the treatment of several chronic diseases and in palliative care, contains equal amounts of THC and CBD extracts, which significantly enhances its calming and pain-relieving effects. Accordingly, CBD in the mixture also balances the effect of THC, resulting in a notable absence of overdose incidents, which can occur with pure THC extracts. The product is sold as an oral spray.

Recent studies in cannabinoid pharmacology have also established that CBD can significantly slow the breakdown of psychoactive organic compounds in the body, which explains its ability to increase the strength and duration of THC’s effects when used together. It is important to note that this effect extends to many other psychoactive compounds. For this reason, CBD can also synergize with painkillers, enhancing their effect, and may cause negative reactions with certain antiepileptic drugs, leading to their excessive accumulation in body tissues.

Regarding the direct use of cannabinoids in cancer therapy, a 2014 study reported that a combination of cannabinoids and radiation therapy could significantly reduce the growth rate and induce the death of cancer cells. Animal experiments showed that, individually, both therapies had relatively minor effects on the growth of diseased cells. However, using radiation together with a cannabis extract containing equal proportions of THC and CBD was able to almost completely stop tumor growth in rats, in some cases even destroying clusters of malignant tissue.

Currently, several private studies report successful use of cannabis in combination with other therapies for treating various forms of cancer in laboratory animals and human volunteers. These include the following studies published in the last 10 years:

• Use of cannabis and temozolomide in the treatment of brain tumors (Torres, 2011)
• Use of THC extract and gemcitabine in the treatment of pancreatic cancer (Donadelli, 2011)
• Use of synthetic anandamide in combination with paclitaxel in the treatment of small intestine tumors (Miyato, 2009)
• Use of synthetic cannabinoid HU-210 together with 5-fluorouracil in the treatment of colon cancer (Gustafson, 2009)

The authors of these studies note that some forms of cancer cells may be resistant to certain types of therapy, including the use of THC or CBD. For this reason, to increase the overall effectiveness of treatment, it is better to use these substances in combination, in equal proportions. It is also important to combine or alternate cannabinoid therapy with other cancer treatment methods and to gradually increase the overall dosage of cannabinoids during treatment to prevent rapidly mutating cancer cells from adapting to new aggressive conditions.

It is worth highlighting the challenges of using cannabis in treating tumor forms whose mutations affect the function of important signaling molecules in the body, such as midkine and amphiregulin, which are responsible for transmitting nerve impulses from the body’s endocannabinoid receptors. When receptor signaling is blocked, such complications can nullify the therapeutic effect of THC and CBD. However, chemotherapy and radiation can affect malignant cells, making them vulnerable to cannabinoids again.

In short, while cannabis cannot be fully considered a cure for cancer, its usefulness in managing and treating certain forms of the disease should not be dismissed. When used together with other types of therapy, a mixture of THC and CBD can have a real effect on the growth and development of tumors, up to and including the death of malignant cells.