Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Chemotherapy Easier on Pets than on People

Pet Column for the week of October 9, 2000

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
By Carrie Gustavson
Information Specialist

Cancer therapy is a rapidly expanding discipline in veterinary medicine. For many forms of
cancer, chemotherapy is a treatment option to prolong the life of your pet. But we've all
heard of the very radical, toxic therapies often given to human cancer patients battling
cancer. So the first question on many people's mind is: why would I want to put my dog or
cat through that?

"There is a lot of taboo surrounding chemotherapy for pets," says Dr. Tim Fan, a
veterinarian who specializes in oncology at the University of Illinois Veterinary Teaching
Hospital in Urbana. "Many clients have seen a family member or friend with cancer go
through chemotherapy."

The problem is that this perception of chemotherapy is not very accurate when it comes to
animals. "Often people will make the decision not to treat their pet based on what they've
seen or heard about human treatment, before they learn about treatment for animals," says
Dr. Fan.

Animal chemotherapy is much milder than human chemotherapy. This is because human and
veterinary oncologists have very different goals for treatment, and therefore the intensities,
side effects, and outcomes are also very different.

"With humans, the intent is to cure the patient. This may mean aggressive chemotherapy,
radiation treatment, and radical surgery. It is a more aggressive protocol with much more
severe side effects," says Dr. Fan. And for humans, there are support measures, such as
bone marrow transplants, which are not yet available in veterinary medicine, so the
treatment can push the envelope to a dangerous level in order to attempt to cure the cancer.

"Most people will settle for a cure at any cost. That's why six months of chemotherapy with
all the intense side effects may be worth it," says Dr. Fan.

In animals, the difference is that, because the cancer is usually fairly advanced by the time it
is discovered, many times a cure is not possible. So instead of going for a cure,
veterinarians aim to extend the pet?s life while allowing the highest quality life possible. "The
emphasis is on how good we can make an animal feel while he is alive. We chose quality of
life over quantity," says Dr. Fan.

For example, veterinary oncologists typically combine three drugs for an effective therapy
versus the ten or so typical for humans. With such a protocol, veterinary oncologists can
achieve remission with minimal side effects and an excellent quality of life for their patients.

Often the drugs selected will have different modes of working and different side effects, so
no one system in the body is overwhelmed. Veterinarians have had good success rates with
the protocols designed for animals. The extra time people get to spend with their animals is
much appreciated, and they are pleased with the quality of life chemotherapy achieves for
their pets.

Pet owners need to consider the potential for success with chemotherapy versus no
treatment. "The most common tumor we see in dogs in lymphoma," says Dr. Fan.
"Lymphoma is extremely rewarding to treat with chemotherapy because the animals
respond really well. The average golden retriever with lymphoma will live 13 to 16 months
on combination chemotherapy with an excellent quality of life." Keep in mind that six
months or a year of remission in animals may be equivalent to a 2- to 7-year survival period
in a human.

Learning that a pet has cancer is very difficult. You are suddenly flooded with all sorts of
emotions and questions. And the choices to be made have no easy right or wrong answers.
The decision is a very personal one. "The decision to pursue chemotherapy has to be a joint
decision between you, your veterinarian, and all family members. Everyone should support
the decision and be there for the pet in the rare case of complications," says Dr. Fan.

Until a cure for cancer is found, veterinarians and human doctors must work with the tools
available to provide patients the highest quality of life for the longest possible time. If your
pet has cancer, chemotherapy is an option you should consider carefully. Discuss the details
of your pet's specific case with your local veterinarian.