Canine cancer draws research efforts from human, veterinary sides

CORVALLIS, ORE. — Canine cancer is presenting new opportunities for veterinary and medical researchers to develop new treatment strategies.

Specifically, two universities launched a collaborative canine cancer project at Corvallis-based Oregon State University (OSU) and Portland-based Oregon Health & Sciences University. They are aiming to blend customized chemotherapy and surgery for the treatment of canine cancer. These combined efforts mark the first such endeavor of its kind, according to the universities. Part of the project involved a 9-year-old Golden Retriever that was diagnosed with hemangiosarcoma and was brought to OSU's College of Veterinary Medicine.

There, Stuart Helfand, DVM, a professor of veterinary medicine, cultured the dog's cancer cells and experimented with a few new drugs to see their effects on the cells.

The dog was being treated for the unique characteristics of its tumor. The customized treatment approach is an evolving method, he says.

In addition to his work on this hemangiosarcoma case, Helfand is collaborating with Bernard Séguin, DVM, Dipl. ACVS, a surgeon and an assistant professor of veterinary medicine, on treating canine osteosarcoma. Seguin spoke with DVM Newsmagazine on his work with Helfand and their joint efforts with human medicine.

"In our research on osteosarcoma, the dog is an excellent model to understand and study what goes on in humans. Whatever gains we make in dogs can be really helpful to explain what goes on in children," Séguin explains.

"The great value of working together is the access it provides us to resources that would otherwise be difficult, perhaps even impossible, to access. For one, funding on the human side is so much greater than on the veterinary side. It would be very difficult for us to think we could achieve the same level of research just from a financial aspect," Séguin says.

"Also, what is even more exciting is the synergy between the two teams. We can come together and develop protocols, while each bringing our own perspective to the table," he adds.

Some of the cancer research being conducted by Helfand, Séguin and colleagues is based on analyzing compounds called tyrosine kinase inhibitors. The veterinary experts are working with researchers on the human side who worked to develop the first tyrosine kinase inhibitor, which influenced the course of treatment of chronic myelogenous leukemia in people a decade ago. The goal is to investigate how other TKIs may help treat hemangiosarcoma in dogs.

Thus far, test of the Golden Retriever's cells found the cells to be responsive to dasatinib, a TKI that was not approved for veterinary use. So, researchers are attempting to use low doses of the TKI at first to measure the dog's tolerance.

Getting the human and veterinary sides to join forces was largely attributed to the legwork of Charles Keller, MD, who is in pediatric oncology at OHSU, and was looking to collaborate with veterinarians. According to Séguin, Keller really understands the value of the research done in veterinary medicine and can still be very ethical about it.

"What I admire about him," Séguin says, "is that it's never been, 'We're going to do whatever it takes at the cost of dogs,' — it's always been, 'We'll do what's right for dogs, and we'll hopefully be able to use that for humans.' "

So far, Séguin says he's encouraged by the results with regard to chemotherapy and use of surgery to treat canine cancer.

"It's incredibly promising for the time being, but it is too early to know if it's going to change how we treat the disease, because the results are not mature enough. We're not at a point where we're changing the standard of care, especially since most of our research to date has been in vitro."

The message to veterinarians who are treating osteosarcoma or even hemangiosarcoma in dogs: "Don't give up yet," Séguin says.

While researchers have made progress for dogs with osteosarcoma in removing the tumor and saving limb function, he says there's no standard for limb sparing yet.

Overall, he says, the take-home messages are simple: Limb sparing is becoming more successful than it was in the past because newer technology allows veterinarians to perform limb sparing with greater success.

Secondly, there are a number of drugs that have been developed by pharmaceutical companies that may change how veterinarians treat osteosarcoma and other cancers.

Lastly, he says, "the future is bright. We're going to crack the nut one of these days. We won't give up. Personalized medicine seems to be the way veterinary medicine, especially regarding cancer, will be practiced in the future."

For example, in cases of osteosarcoma, he says, "Basically it is naive of us to think that every dog or every human with the same disease should have the same drugs and will have the same response. We've learned by now that osteosarcoma is very different from one patient to another, and likewise, that patients will respond differently to each drug."