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How dogs and cats are helping to solve a medical mystery

Dog, as well as being man's best friend, is the only other creature on Earth known to die from cancer of the prostate.

Which is why Bernie is in intensive care. His giant head resting on his paws, the massive Bernese mountain dog is recovering from the removal of a blockage that was making it difficult to relieve himself.

The doctors feared that it was prostate cancer. The biopsy will prove them right.

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Around the corner in the oncology ward, a mixed terrier named Dakota is getting over a blast of radiation to treat a nasal tumour and a sarcoma on the hip.

Down the hall, Milou, a snow-white Great Pyrenees, roams around, albeit gingerly because of a large tumour on her right, front paw, waiting to have the CT scan that will determine how far her bone cancer has spread.

Elsewhere, a cat with a suspected brain tumour is having an MRI. A golden cocker spaniel, which arrived two weeks ago from Korea, is being prepped in the oncology ward for treatment for cancer in its ear canal. And radiation therapist Kim Stewart has just finished treating a 150-pound, pot-bellied pig.

At first blush, it looks like an episode of Celebrity Pets featuring overly sentimental people willing and able to drop serious money on high-tech medical care for Spot and Rover.

Doctors and health-care professionals who research and treat cancer in pets are familiar with criticism from those who can't fathom why resources are directed at animals, when there's so much more to do in the fight against cancer in humans.

But the oncologists and their support team at Guelph are well past the sneers and jeers, primarily because they have been able to prove the bond between pet and owner has an added dimension: Patients of the Animal Cancer Centre at the University of Guelph's world-renowned Veterinary College also are taking part in scientific research.

I know some people don't understand giving money to a research program for animals... But in my mind, it's all one biology as far as cancer is concerned. Elizabeth Stone, dean of the Ontario Veterinary College

They are helping to develop new treatments for animals that, in turn, are expected to result in breakthroughs in human care - a contribution so vital that it is in large part responsible for the $20-million expansion of the centre that should be finished next year.

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For years, cancer research was the work of rodents. Mice and rats received injections to induce tumours that were then used to evaluate potential therapies. But there was a big problem: Rarely did something successful with a lab rat work well when tried on a human.

Frustrated, comparative oncologists - the collective medical (human) oncologists, veterinary oncologists, academics and pharmaceutical companies who have been studying cancer in different species for 30 years - began to pay more attention to pets, especially dogs.

"If it wasn't such a struggle, if cancer research was efficiently done, and wasn't so expensive, there might not be this need," says Tony Mutsaers, a veterinary oncologist at the centre who is also finishing his PhD in medical biophysics at the Sunnybrook Health Sciences Centre in Toronto, an hour's drive to the east.

"But the dog is now viewed by many as a plausible stepping stone."


That's within the research community, of course. "One of the things that continues to amaze me is how many people don't realize that animals get cancer, even physicians," says Elizabeth Stone, dean of the veterinary college, which began training vets in 1862 and boasts graduates such as W.G. Ballard, of pet-food fame.

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"Just the fact that we call our facility the Animal Cancer Centre hopefully will make people realize, yes, animals get cancer. And, yes, their physiology isn't that different from the No. 1 species."

And so they have veterinary oncologists such as Paul Woods and Sarah Boston to care for them and they receive the same consideration human patients do.

Ms. Stewart, the radiation therapist, worked in a human cancer ward before transferring to the centre. She takes photos of her clients to post on her "wall of stars" - a cheerful gallery of dogs, cats, horses, ferrets, the odd pig and even a bunny.

The waiting room may resemble a zoo at times, but the vast majority of the patients are cats and dogs, whose sheer numbers provide a vast research pool.

Consider the facts: Canada has roughly eight million dogs and cats. One in four dogs will develop cancer, as will one in eight cats.

As well, naturally occurring cancers in dogs (unlike the cancers induced in mice) are biologically and clinically similar to those in humans - such as non-Hodgkin's lymphoma, melanoma and soft-tissue sarcoma.

In addition to lethal prostate cancer shared by dogs and people, the type of breast cancer that affects dogs spreads to bones, just as it does in women. And the most frequent canine bone cancer, osteo- sarcoma, is the same one that strikes people such as Terry Fox and Ted Kennedy Jr. in their teens.

In fact, it was Stephen Withrow, an internationally acclaimed scientist and professor at the College of Veterinary Medicine and Biomedical Sciences at Colorado State University, who made an important breakthrough working with dogs afflicted with osteosarcoma. He and his team developed a revolutionary limb-sparing technique that has been widely adapted for use on humans, significantly increasing the likelihood that children diagnosed with osteosarcoma will be cured.

Canine cancers, Dr. Mutsaers adds, also mimic those of humans in another way - metastasis, the often life-threat- ening spread of cancer cells to distant sites throughout the body.

As well, canine tumours - like those in a dog's owner - are influenced by the same key factors: age, nutrition, sex, reproductive status and environmental exposure.

"They're eating the same food. They're breathing the same air," says Geoff Wood, an associate professor of pathobiology at the college. "They're not contained in a germ-free environment. They have exposure to everything that we're exposed to. Physiologically, they're more like a human than mice are."

And, as in human cancer, canine cancer patients are treated with surgery, radiation and chemotherapy.

Dr. Wood, who heads a cancer-research program that uses both mice and dogs, says a turning point came with the public release in 2004 of the canine genome, which gave researchers the genetic arsenal they needed to "understand cancer in dogs, the same way we understand cancer in humans."

For two years, he has been designing a dog gene chip that he plans to use to compare the DNA of normal and diseased animals to uncover specific "markers" - bits of genetic material associated with disease genes. He expects to learn which genetic clusters are bad or benign in various patients - a technique that he hopes will lead to a better understanding of how human cancers progress.


Established in 2007 as part of the university's Institute for Comparative Cancer Investigation, (which promotes greater integration of research in basic cancer biology and veterinary medicine), the Animal Cancer Centre currently has a staff of six, but the $20-million expansion, largely financed by the OVC Pet Trust Fund, will allow it to grow greatly, with the addition of: a medical oncologist, surgical oncologist, radiation oncologist, internal medicine specialist, medical oncology resident, surgical oncology resident, radiation oncology resident, three interns, five technicians and an additional four veterinary students.

Currently the cancer ward has about 2,500 patient visits a year, more often from communities in Ontario, Quebec, upstate New York and the Maritimes than far-off Korea. When the new centre opens next year, Dr. Stone, the college dean, expects that the patient load will triple.

Even without the new quarters, the centre's profile is on the rise. It was recently invited to join a U.S. consortium of top veterinary-teaching hospitals put together by Chand Khanna, a graduate of the Western College of Veterinary Medicine in Saskatoon, who interned at Guelph and is now head of head of the Comparative Oncology Program at the U.S. National Cancer Institute in Maryland.

Dr. Khanna, who was born in Kenya and moved to Toronto at the age of 3, created the Comparative Oncology Trials Consortium to track canine cancer treatment specifically to help develop drugs destined for human use.

Dr. Mutsaers calls it "a wonderful collaborative effort."

"We can enroll 100 bone cancer dogs at a time, or 50 with melanoma," he explains.

"These numbers, and the biological nature of the questions that can be answered, has led regulatory agencies like the Food and Drug Administration, and large and small pharmaceutical companies, to start to consider what questions our research might answer."

The Guelph centre is the first Canadian institution invited to join the effort, which Dr. Khanna says he hopes will lead to important breakthroughs.

"The problem with the conventional approach is that it's a one-way path, which often answers a very small set of questions and leaves many unanswered," he says. "To move a cancer drug from inception to a pharmaceutical product can cost from $800-million (U.S.) to $1-billion (U.S.). And even then, very few get approved.

"We see comparative oncology as a way to simply add more information to the process. Information that is critically needed to successfully bring new cancer treatments to patients."


Research benefits or not, cancer treatment - whether that's radiation or chemotherapy - doesn't come cheap. And the cost varies based on the type of cancer, the size of the dog, and in the case of chemotherapy, the drugs that are used.

The typical cost of multi-agent chemotherapy for a dog that has lymphoma and weighs 25 to 30 kilograms ranges from $3,000 to $4,000 for 16 treatments.

Radiation therapy is even more costly: A dog with a nasal tumour requiring 20 to 24 treatments given daily and under general anesthesia for four or five weeks could cost $4,500 to $5,000.

Guelph resident Penny McDonald has been bringing in her dog, Max, for radiation and chemotherapy for osteosarcoma since January, and figures she has spent about $6,000 so far.

But, like most pet owners, she doesn't begrudge the expense. "As long as he's happy and not in any pain, I will keep doing the treatment," says Ms. McDonald, who has lost three dogs to cancer in as many years.

Max, who is a cross between a Bernese and a golden retriever, is turning 10 and takes painkillers and a bone-strengthening drug similar to that prescribed for women suffering from osteoporosis.

He is also part of a clinical trial conducted by Dr. Boston, who is a surgical oncologist, and has Max come in every three weeks to run on a "force plate" treadmill, which measures his gait and gives her an indication of whether the meds or the radiation need to be altered.

"I'm hoping Max is going to be around for at least a year," his owner says. "I've had dogs my whole life and I can't imagine being without one. Max can't make it up the stairs any more, so he and I both sleep in the family room."

Her first retriever, Jenny, died of lymphoma after having chemo for 13 months. Ms. McDonald lost another golden retriever, Ginger, last November to pancreatic cancer. She has spent roughly $10,000 on cancer treatment, and makes regular donations to the OVC Pet Trust Fund, which provides research grants as well primarily funding the cancer centre's expansion.

Dr. Stone admits that some people are amazed at what pet owners will spend but cautions those without a pet not to pass judgment.

"It's a very personal decision, and it depends on the bond between that individual and their pet. And I know some people don't understand giving money to a research program for animals, as opposed to one for human beings. But in my mind, it's all one biology as far as cancer is concerned," adds Dr. Stone, who also recently lost her dog, Majic, to cancer.

"It seems to me our cancer centre gives you two bangs for the same buck."


Finally, her wandering over, Milou, the Great Pyrenees, is prepped for her CT scan, and rolls by on a gurney already fast asleep.

Her cancer was diagnosed a year ago, and owner Hari Menon, whose wife drives Milou into Guelph from nearby Waterloo, was told their dog probably had another six months.

Mr. Menon calculates the visits have cost him $7,000 to $8,000. "We decided to let her have a good life," he explains, "and we'll keep doing the treatment as long as we can."

Postscript: "As long as we can" turned out to be not long at all because the CT scan did not go well, and Milou lost her battle.

But staff at the centre say they won't soon forget the gentle giant who was such a fixture for so many months - and to help them remember, Kim Stewart has given Milou's photo a place of prominence on her wall of stars.

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