February 7, 2010
Every once in a while, a new product becomes available in veterinary medicine that really makes a difference. Last year, a product was approved by the US Dept. of Agriculture to treat canine oral melanoma. I find this product particularly interesting because it is actually a vaccine against cancer.
However, instead of being a vaccine to prevent a disease, this vaccine is used therapeutically, after the pet already has developed a melanoma. There is some consideration being given to use of this product as a preventive vaccine, but trying to determine which dogs are likely to get a melanoma is nearly impossible. So, who would you vaccinate?
Canine oral melanoma is a tumor that forms in the mouth of dogs. It tends to be very aggressive and quickly invades local bone and soft tissue. Unfortunately, by the time pet owners are aware that there is something growing in their dog’s mouth, the tumor is quite advanced. Major surgery is usually required to remove as much of the tumor as possible. Radiation is then recommended to “attack” the cancer that could not be removed by surgery. Some chemotherapy regimens have been shown to slow down tumor growth, but most dogs with melanoma only live one to five months after diagnosis, even with conventional therapy.
The canine melanoma vaccine teaches the dog’s immune system to recognize the presence of a melanoma tumor protein called tyrosinase. The stimulated immune system then attacks the tumor cells as if they were any other foreign material that doesn’t belong in the body. Pretty neat huh?
But, it isn’t perfect. Dogs with oral melanoma still need to have surgery and or radiation to reduce the tumor to the smallest size possible. Then the vaccine can be given in four doses at two-week intervals. After that it is boosted every 6 months.
In a recent study, dogs receiving the vaccine in conjunction with surgery and/or radiation lived on average 389 days. The dogs that only got surgery and/or radiation lived 60-150 days. So, you can see that the vaccine really helped extend the lives of these dogs.
Whenever a dog gets any kind of cancer, it can be truly devastating for everyone involved. But, this vaccine is an example of promising new hope for dogs. As the developers continue to improve this technology, they will also begin to look at similar technology for multiple types of tumors. It will be interesting to see if other types of cancer respond in a similar manner.