Brain cancer strikes French bulldogs disproportionately often, and a Frenchie named Devon is contributing to some very important research on this awful disease.
Dogs are the only other animals in whom brain cancer behaves just about the same way it does in human beings, which means that research on canine brain cancers can help provide diagnostic and treatment methods that may help people with brain cancer. Most primary brain tumors (those arising in the brain, as opposed to metastasizing there from some distant organ like breast or colon) arise from a type of cell in the brain called glial cells, ‘glia’ being the Greek word for glue. These glial cells form connective tissues that surround and support the brain’s nerve cells, and there are several types of glial cell tumors, or gliomas (such as astocytomas, oligodendrogliomas, and glioblastomas).
Although the incidence of primary brain tumors in dogs is not high, being about 14.5 per 100,000 for dogs in general, there are four breeds that account for more than half of those cases: Bulldogs, French Bulldogs, Boston Terriers and Boxers. The other 157 AKC breeds (plus mixed breeds) account for the rest. These pie charts illustrate this astonishing disparity between breeds.
A dog of one of those four breeds is 25 times as likely to develop brain cancer as any other dog.
So is anything being done about this?
Yes!
There are two lines of attack for this problem: improving diagnostic and treatment methods for affected dogs, and trying to understand the molecular and perhaps genetic basis for this so that in the future a test might be developed to determine what dogs are at risk of developing and perhaps of transmitting it to their offspring.
DIAGNOSIS AND TREATMENT: DEVON’S STORY
Brain cancer can cause many different types of symptoms, depending on where in the brain it is located. Those changes can be physical (head tilt, uncoordinated movements, loss of vision) or behavioral (circling, loss of learned behaviors, temperament problems). But the one symptom that generally tells the owner that there is a problem is when the dog develops seizures for which no other cause can be found (such as trauma, toxic exposure, metabolic problems). In an old dog of 8 to 10 years, seizures are assumed to be caused by brain cancer, and no further diagnostic procedures are done. Instead the seizures are controlled by drugs as well as possible and nature is allowed to take its course. In young dogs, 2 or 3 years old, sudden onset of seizures, once other causes are ruled out, in the past was just diagnosed as ‘idiopathic epilepsy,’ the word idiopathic meaning ‘unknown cause.’
Last November, Devon developed seizures at age 3 years. His owner Susan Bunyard had noticed behavioral changes for a while prior to the seizures, and at the suggestion of her vet, she took Devon to the University of California Vet School at Davis, where there is an excellent neurology department that is working closely with the Department of Neurosurgery at the University of California/San Francisco Medical School. Susan took Devon to UCD where an MRI scan of the brain revealed a tumor in the frontal lobe…. the area in the forehead region. A new diagnostic procedure was done in which a small hole was made in the skull right over the tumor as the vet watched guided his instruments with a CT scan. A very small needle was inserted into the tumor with the CT scan allowing it to be accurately positioned and some tissue was withdrawn for biopsy, which showed that the tumor was of a type called oligodendroglioma.
With no treatment, Devon’s life expectancy was estimated to be only a couple of months. However Susan learned that he was eligible for an experimental treatment program that might extend this considerably, as it had for other dogs. Given his young age and otherwise good medical condition, Susan decided to let Devon participate.
A small cylinder was surgically implanted in Devon’s head right next to the tumor with tiny needles extending from the cylinder into the tumor mass. A chemotherapy agent was loaded into the cylinder and slowly dispensed over time into the tumor. Brain tumors normally can’t be treated effectively with chemotherapy because the brain protects itself from unnatural substances in the bloodstream with a cellular “blood-brain barrier” which prevents the chemo from leaving the bloodstream and getting into the tumor tissue. This direct injection of the agent into the tumor is the way that researchers hope to get around this problem. It also avoids the unpleasant side effects that chemotherapy delivered by the bloodstream often causes, since the agent goes only into the tumor and not into any other tissues.
A follow-up MRI done several months later showed that not only had the tumor not grown, but that it was smaller than before. And the tissue around it which had looked abnormal before treatment looked normal on follow up. More importantly, Devon feels and acts well, except for the persisting seizures which are not expected to go away.
Devon was the 11th dog to receive this treatment, and because of his response to it five human beings have been accepted into the same program at the University of California at San Francisco Hospital. So whatever his future, Devon has already given much, and not just to dogs but to people as well.
Anyone whose dog is diagnosed with brain cancer must consider many different factors. In an old dog, the time gained might not be worth putting the dog through any sort of treatment other than trying to make it comfortable. Also, financial pressures are great as the cost of an MRI is high, and unless the owner has decided to pursue some treatment, it would be of little benefit to obtain an accurate diagnosis. But in a young and otherwise healthy dog, the owner may wish to consider treatment. Dr. Dickinson, who is one of the UC Davis vets caring for Devon, has written a letter for referring veterinarians that you can download HERE and give to your vet. It outlines the clinical trials currently going on at UC Davis so that if the vet has a patient that might benefit from it they can discuss it with the owner.
HOW YOU AND YOUR DOG CAN HELP
In addition to the diagnostic and treatment research being conducted, a second line of attack on this disease aims to identify any underlying genetic causes. Click here for information about this research which is being conducted at UCD by Dr. Danika Bannasch. In the brain cancer study, Dr. Bannasch needs blood samples from affected dogs with brain cancer as well as from older unaffected dogs; they do not have to be relatives.
For this research, blood samples are needed, and if tumor samples are available (either taken at surgery or postmortem) those would also be helpful. The researchers can pay for expenses of tumor tissue collection and shipping. Most vets are happy to draw blood free of charge for research projects, and shipping need not be overnight. For information about blood sample collection, preparation and shipping click here. And for the sample identification form to accompany samples, click here.
If your Frenchie should be diagnosed with or suspected of having a brain tumor, please consider helping with this important research.
