Treatment developed for canine malignant melanoma

2/4/2008 5:33 AM
By: Ivanhoe Broadcast News

Malignant melanoma is an aggressive form of cancer that can be found in humans and dogs.

In humans, it is often associated with the sun. But in dogs, it is often found in the mouth and is called canine malignant melanoma.

Owners may notice difficulty chewing or a strange odor in their dog's mouth. Canine melanoma is the most common type of oral cancer in dogs and can account for almost 5 percent of all cancers that veterinarians diagnose.

It can also appear in the nail bed, foot pad or other areas. It can happen in any breed of dog but is more common in those with dark pigmented skin. The outlook is not good for dogs whose cancer is diagnosed late or has spread. The prognosis is usually only a one- to five-month life expectancy.

Dogs are often treated with surgery and radiation. Studies have shown that this type of melanoma is often not responsive to chemotherapy treatment.

Researchers from The Animal Medical Center in New York and the Memorial Sloan-Kettering Cancer Center collaborated on a treatment for canine malignant melanoma. They developed a type of vaccine that can kill this aggressive type of cancer in dogs. They hope this will pave the way for human treatments.

The vaccine is DNA-based, and dogs given the vaccine create antibodies against the proteins coded for by the DNA. This creates antibodies against the cancer as well, so the body kills off cancer cells in the dog.

Studies have shown that dogs that receive surgery or radiation as well as the vaccine live three-times longer than expected, and some dogs survived another three years. The vaccine is also being tested in humans.

"Both humans and dogs develop this cancer in exactly the same way. The disease occurs spontaneously through an interaction of genes with the environment," says Jedd Wolchok, M.D., Ph.D., an oncologist on the Clinical Immunology Service at Memorial Sloan-Kettering Cancer Center. "By conducting trials in humans and in animals that live in the same surroundings as humans, there can be a synergy that we hope will result in improved cancer treatment for all."

In 2007, the USDA approved the use of this vaccine for the use in dogs with canine melanoma. The treatment is only available from veterinarian oncologists. The vaccine is given via a new Canine Transdermal Device, which delivers the vaccine without the use of a needle. It is given four times, two weeks apart.

A booster vaccine is given every six months after treatment. The cost of the vaccine is around $1,000, but dogs also undergo surgery or radiation, so the cost for total treatment can run $4,000-$5,000.