Onderzoekers kijken naar CBD voor veel voorkomende, moeilijk te behandelen tumorenfebruari 4, 2020
There’s a 3-year study underway at the University of Guelph’s Ontario Veterinary College (OVC) to explore the potential use of cannabis to treat canine bladder cancer — not so much the symptoms, but the disease itself.
A small team of researchers led by Prof. Sam Hocker of OVC’s Department of Clinical Studies are looking at what effect cannabidiol (CBD) has on cancer cells, as well as its effect on chemo and radiation therapies in dogs.
By learning more about the potential anti-cancer properties of CBD, the team hopes to highlight alternative therapies to help manage the disease, especially for a common but hard-to-treat form of bladder tumor called urothelial carcinoma (UC). According to a University of Guelph news release:
“Hocker will study the effects of CBD on bladder cancer cell lines. He hopes to learn whether the substance kills cancer cells and how it works, including whether the process involves endocannabinoid receptors occurring naturally in the body.”1
The study will focus on three different cell lines from canine bladder tumors. The researchers will apply CBD to the cell lines to determine if it can kill the cells alone (I take this to mean if it kills only cancer cells and not healthy cells) and whether it works better or worse with chemotherapy and/or radiation.2
“The goal of my particular studies is to just evaluate whether cannabis kills cancer cells and if so, by what mechanisms is it doing that,” Hocker told The Star. “So can we treat these dogs with bladder cancer with traditional chemotherapy or radiation therapy in conjunction with CBD and will it change the overall survival or will it extend that survival for this type of cancer dogs have?”3
I’ll be eagerly awaiting updates on this study, since we’ve barely scratched the surface of the potential healing properties of cannabidiol — especially for animals.
Historically, Canine Bladder Cancer Has Been Difficult to Identify
Bladder tumors in dogs, most of which are transitional cell carcinomas (TCC), cause symptoms such as blood in the urine, straining during urination and increased frequency of urination. Unfortunately, these symptoms are also common in urinary tract infections, and in fact, many dogs with bladder cancer may have urinary tract infections (UTI) as well.4
As a result, bladder cancer in dogs can be difficult to identify and is often misdiagnosed as a UTI. Treatment with antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) may temporarily improve symptoms, delaying diagnosis further. This is why most bladder cancer in dogs isn’t found until the disease has spread, and treatment options are limited.
Newly Available Noninvasive Urine Test Offers Early Detection
The good news is there’s a new urine test available that offers a noninvasive way to identify the disease early, even before symptoms develop. Certain dog breeds are at an increased risk of developing bladder cancer, including TCC and UC. This indicates there may be a genetic component involved in the development of the disease, and researchers have found a mutation in the canine BRAF gene in a large percentage of dogs with TCC and prostatic carcinoma (PC).
Bladder cancer sheds tumor cells in urine, and the new test is able to pick up the presence of the mutation with excellent results. According to a 2015 study, the test “identified the mutation in free catch urine samples from 83% of canine UC and PC patients, demonstrating its utility as a noninvasive means of diagnosis.”5
The test, known as the Cadet (CAncer DETection) BRAF Mutation Detection Assay, can detect the mutation at very low levels, as few as 10 TCC or UC cells in the urine, making it useful for early detection, months before clinical signs appear.6 The Cadet test became commercially available in July 2018, and there’s also a Cadet BRAF-Plus test, which detects another biomarker, bringing the sensitivity to more than 95%.
“A positive BRAF test result can substitute for tissue diagnosis (histology, cytology),” veterinary oncologist Dr. Sue Ettinger writes in an article for dvm360.
“If the BRAF mutation isn’t detected, the urine specimen is then assessed by the lab using a proprietary algorithm to determine whether it meets the criteria for analysis with Cadet BRAF-Plus. If eligible, the BRAF-Plus will be run, and no additional urine is required.”7
Because the test is noninvasive, it can be used not only as a diagnostic tool if symptoms are present but also as a screening tool for high-risk breeds. It can also be used to monitor outcomes in dogs undergoing treatment for bladder cancer. As Ettinger notes, the test is groundbreaking because earlier detection can result in lives saved:
“Clinical signs for UC are often subtle, nonspecific and confused for other lower urinary tract diseases. The Cadet BRAF test provides a noninvasive urine test for earliest detection of emerging UC — even before overt signs of the cancer become evident. Timely detection of UC allows owners to direct their resources toward effective treatment of the cancer itself, rather than the nonspecific clinical signs.”
One Important Way to Help Your Dog Avoid Bladder Cancer
A 2013 study conducted at Purdue University concluded that certain garden and lawn chemicals are linked to canine bladder cancer, including common herbicides containing 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxypropionic acid (MCPP) and/or dicamba.8
The dogs’ exposure to the chemicals occurred through ingestion, inhalation, and transdermally (through the skin). Breeds with a genetic predisposition for bladder cancer, including Beagles, Scottish Terriers, Shetland Sheepdogs, West Highland White Terriers, and Wire Hair Fox Terriers are at particularly high risk.
The study showed that most of the dogs from homes using the chemicals had herbicides in their urine. Since some dogs from homes that did not use the products also had herbicides in their urine, researchers concluded the wind could carry the chemicals up to 50 feet from the site where they were applied. My recommendations:
Don’t apply chemical pesticides or herbicides to your yard, and if you use a lawn care service, don’t allow them to use them. Also be aware that a neighbor’s lawn chemicals can potentially contaminate your property and pose a risk to your pet.
Avoid lawn care and other gardening products that contain insect growth regulators (IGRs). And be aware that the chemical pyriproxyfen, an IGR, is used in certain flea/tick spot-on treatments.
Don’t allow your pet access to any lawn unless you can confirm no pesticides or herbicides have been used.
If you think your pet has rolled around on chemically treated grass, bathe her as soon as possible. If you’ve walked your dog (or cat) in a grassy area that might be contaminated, giving her a foot soak as soon as you get home should flush away any chemical residue that may be clinging to her feet and lower legs.
Increase the number of baths and foot rinses spring through fall, when chemical application is highest along public highways, parks, schools, streets and public nature preserves.
If you live in a townhouse or community that applies chemicals to common areas, I recommend “detoxing” a patch of grass in your backyard by watering the chemicals down into the soil to reduce skin contact after application.
Keep your pet on a leash (and on the sidewalk) until you’ve walked to your pesticide-free destination, and consider a periodic detoxification protocol for your pet.