A new study, published in the journal Frontiers in Veterinary Science, has found that cannabidiol (CBD) can be an effective anti-cancer agent for dogs.
Researchers from the University of Chile reviewed eight pre-clinical studies and found that CBD can prevent, stop, or significantly reduce the growth of cells in conditions such as lymphoma, prostate cancer and breast cancer.
The studies showed that CBD can inhibit cancer cell growth and division and cause cancer cells to die by making changes to the cells’ internal communication networks.
“Overall, these findings highlight the potential of CBD as an anticancer agent across different cancer types,” the researchers said.
Cancer in dogs is reportedly up to five times more common in dogs than it is in humans, with between 1000 and 2500 new annual cases of cancer per 100,000 dogs compared to 500 cases per 100,000 humans. More than four million new cases of canine cancer are reported every year in the United States alone.
The endocannabinoid system (ECS) is an important bodily system found in most animals, including mammals, similar to the immune and nervous systems, which helps maintain homeostasis within the body, amongst other roles. Receptors which form part of the ECS, such as the CB1 and CB2 receptors, are known to interact with cannabinoids, including THC and CBD.
Previous research has linked a dysregulated ECS with the growth of cancers in both humans and mammals, and has shown that CBD could have anti-cancer properties. It is these links that prompted scientists in the current study to investigate how effective CBD may be at treating cancer in dogs.
Researchers used statistical analysis to evaluate eight studies that they considered relevant. All the studies were pre-clinical, with all but one conducted in vitro, with the remaining study using a mouse model.
The studies examined how CBD affected cells of different types of cancer; these were: lymphoma, mammary carcinoma, osteosarcoma, glioma, urothelial carcinoma, and prostate carcinoma.
The evidence from the studies demonstrated that CBD can be effective at slowing down and fighting cancerous cells, although researchers were unsure which dose and delivery method were most effective.
“Overall, the selected studies reported an antiproliferative effect of CBD, both in vitro and in vivo, highlighting its potential for treating different types of cancer in dogs. However, there is currently no consensus regarding the most appropriate formulation, as the reviewed studies have not evaluated standardized CBD formulations,” the author wrote.
Other findings from the review gave a mixed picture of how effective CBD can be when used in conjunction with other cancer-fighting therapies such as chemotherapy. Some of the reviewed studies found CBD to help, some found that it could interfere with treatment, and some found that it did both.
“These findings indicate that CBD does not induce uniform effects across different chemotherapeutic agents, as it may induce either synergistic or antagonistic interactions depending on concentration and cell type. However, because these studies used different cell lines and chemotherapeutic agents, direct comparisons cannot be made, and further studies are needed to confirm the reproducibility of these findings,” the authors wrote.
The study concludes by agreeing that CBD can have similar anti-cancer qualities in canines as it can in humans, and that additional studies are required to make firmer confirmations of the current findings.
“From this review, the authors identified a need for additional studies evaluating the effects of CBD in canine cancer, including in vitro studies to confirm the reproducibility of the results obtained to date, as well as investigations in other cancer types in which CBD has shown effects, such as lung and colorectal cancer,” the study said.
“Furthermore, standardizing CBD concentrations and CBD extract formulations is necessary to enable comparisons across studies and facilitate the reliable translation of findings into clinical trials. Additionally, given that safety studies in dogs have shown that CBD is well-tolerated and presents a favorable safety profile, it is feasible to consider future clinical studies to evaluate its antitumor efficacy in dogs.”
