Veterinary Medicine

Man's best friend aids cancer researchers in designing new treatments

January 22, 2010

The Animal Cancer Center at CSU was one of the first centers selected to join the National Cancer Institute's Comparative Oncology Trials Consortium, a first-of-its-kind partnership that allows veterinary oncologists to work collaboratively on novel cancer therapeutics and techniques.

Improve treatments for human cancers

Meredith Razey, an oncology nurse with the Animal Cancer Center, takes care of a canine patient at the Veterinary Teaching Hospital.

Pet dogs with spontaneously occurring cancer may provide researchers with important information on how to improve diagnoses and design more effective treatments for human cancers, a new research report from the National Cancer Center suggests.

Results from studies using dogs rather than laboratory mice have proven to be more useful in developing new cancer drugs and other treatments because naturally occurring tumors in dogs are biologically and clinically similar to those in human patients, NCI scientists found.

Ladder of research testing

“As you travel up the ladder of research testing – beginning with the petri dish, and then testing ideas in mice – it’s a giant leap from mice to humans,” said Dr. Stephen Withrow, director of the Animal Cancer Center at Colorado State University.

“Put the dog in the middle, though, between mice and people, and your chances of a home run are increased.”

According to estimates from the NCI, as many as 6 million new diagnoses of cancer occur in dogs in the United States each year, with almost as many in cats. Just as in human disease, canine tumors are influenced by:

  • age
  • nutrition
  • sex
  • reproductive status
  • environmental exposure

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

Pet owners often highly motivated to advance cancer research

With canine patients, pet owners are often willing to try new cancer treatments or enroll their pets in investigational trials if they think it will be effective in treating the disease. Many pet owners are also highly motivated by the opportunity to make a contribution to the advancement of cancer research, which has helped to increase opportunities in comparative oncology.

Comparative oncology is the study and treatment of animals with naturally occurring cancers, which is translated to the biology of human cancer. This concept is not new. Over the past 30 years, researchers have increasingly used this approach to improve the understanding and treatment of several human cancers, such as lymphoma, melanoma, bone cancer (osteosarcoma), and many others. 

Share findings

Professor Stephen J. Withrow, director of the Animal Cancer Center and a University Distinguished Professor, shown with a human and a canine cancer survivor.

However, advances were slowed because there was no infrastructure set up to allow human and veterinary oncologists, drug developers, and basic scientists to share their research findings with one another. Now, that has changed.

The National Cancer Institute’s Comparative Oncology Program, working with the nation’s best veterinary schools, has formed the Comparative Oncology Trials Consortium, or COTC. The COTC is a group of selectively chosen veterinary oncology centers located within veterinary teaching hospitals in the U.S. that work collaboratively on cancer research.

Each veterinary hospital member has met rigorous guidelines related to staffing and equipment, including a dedicated clinical trials coordinator, tumor tissue banking capability, sophisticated imaging equipment, and experience in electronic data reporting.

Animal Cancer Center a pioneer

The Animal Cancer Center at CSU was one of the first centers selected to join the COTC; a working partnership that Withrow described as the “first-of-its-kind that allows veterinary oncologists in the best veterinary schools in the country to work collaboratively on novel therapeutics and techniques.”

Any one of these studies, Withrow points out, could lead to important breakthroughs for human and veterinary medicine.

Working closely with the NCI’s Comparative Oncology Program, the consortium can design and execute clinical trials in dogs with naturally occurring cancers, then share results with all members. NCI scientists said that an important advantage to using clinical trials in pet dogs is that they are not constrained by the same rigid guidelines applied to human oncology trials.

This more “unstructured” approach allows novel, investigational drugs or treatments to be offered to canine cancer patients. Dr. Susan Lana, chief of clinical oncology service at the CSU Animal Cancer Center, agrees that there are many advantages to running canine clinical trials.

More comfortable trying new things

“Unlike in human oncology medicine, there is often no ‘standard of care’ for many cancers we see in animals,” Lana explained. “For example, in the final phase of a trial, scientists are comparing the standard of care treatment that already exists for that particular disease to something new being studied. That ‘something new’ has to be more effective, cost less, or be less toxic for it to move forward. In dogs, if there is no standard of care for that disease, clinicians as well as owners feel a lot more comfortable trying new things because what is currently available does not work.”

As an example, Lana cited a common canine cancer, hemangiosarcoma, which originates in the tissues lining blood vessels and the spleen, and is highly malignant.

“Since it can spread almost anywhere in the body, it has a poor prognosis and very short survival times,” Lana said. “What we have currently doesn’t work very well, so anything that we are studying that has good science behind it – whether it’s in mice or in the petri dish – is seen as something worth trying.”

Shorten time it takes to move forward 

Withrow and Lana explained that the normal discovery process can take years to go from bench to bedside – or kennelside, in the case of canine cancer. Study findings in mice did not always successfully translate to human disease because of the tremendous physiological differences. Many features of human cancer do not appear in the mouse model, including long periods of latency, genomic instability, and differences in tumor cells.

“The goals of the consortia are to answer specific questions related to new treatments,” Lana said. “So, our canine patients are providing information that could shorten the time it takes to move forward, to perhaps find that treatment that will extend a cancer patient’s life – human or canine.”

Excerpt from story originally published in the College of Veterinary Medicine and Biomedical SciencesAnimal Cancer Center News, Winter 2010.