By By Don Vaughan

In late 2023, Klydee, an 11-year-old female terrier mix owned by Jeanne Maeda and Lori Tsuhako of Honolulu, Hawaii, developed a bulging right eye and worsening vision that ultimately led to blindness. Klydee was evaluated by a surgical oncologist in Honolulu, who identified a mass at the back of her right eye, arising from nervous tissue.

Klydee's tumor was initially removed, but tumor cells were left behind. Because radiation therapy is not available in Hawaii, the dog was subsequently referred for radiation therapy at the UC Davis School of Veterinary Medicine's Comparative Cancer Center.

When Klydee was evaluated by the radiation oncology team, a second tumor in her brain was found, and there were concerns her initial tumor was regrowing in the front of her brain, causing multiple lesions. The neurosurgery team was brought in to remove her cancerous tissue. It was a delicate procedure because her tumors were in critical areas of the brain and the risk of complications was high.

Neurosurgeons Ji-Hey Lim, DVM, PhD, DACVIM (Neurology), Adrien Dupanloup, DVM, DACVIM (Neurology), and Vishal Murthy, DVM, DACVIM (Neurology), who specialize in complicated brain surgeries, turned to a new, state-of-the-art surgical microscope, a gift from the Meadowview Foundation, to save the patient. The microscope provides much higher magnification and lets doctors view areas that were previously all but impossible to see through an endoscope, enabling less invasive tumor removal and cleaner margins.

"Margin identification is one of our main goals when treating dogs and cats with brain tumors; it is also the center of our research program with this microscope," writes Dr. Dupanloup in the Fall 2025 issue of UC Davis' CCAH Update.¹ "We are exploring how to achieve the smallest margin and increase our chance to get all of the mass."

The surgery was a success, and Klydee returned home after completing a course of radiation therapy to try to keep the tumor from recurring with zero brain deficits. The dog continues to do well today.

A growing facility

Klydee is just one of the nearly 3,000 animals reportedly brought to UC Davis annually for the diagnosis and treatment of cancer. In recent years, the UC Davis Comparative Cancer Center has added a wide array of innovative equipment and oncology specialists.

The facility was established in 2007 as an offshoot of the earlier Cancer Biology in Animals program, and integrated expertise from the School of Veterinary Medicine and the UC Davis NCI Designated Comprehensive Cancer Center, which received its designation in 2012. The Comprehensive Cancer Center is unique in that it was the first program in the U.S. to focus on cancer research across species. The veterinary cancer center currently utilizes 18,000 sf of clinical/research/administration space. This will reportedly increase to 36,000 sf by the end of the decade, when other clinical services currently in that space move to new facilities.

Treating animals with cancer is the center's primary mission, but as its name suggests, its work extends far beyond that, according to Michael Kent, DVM, MAS, DACVIM (Oncology), DACVR (Radiation Oncology), DECVDI (Radiation Oncology), director of the Center for Companion Animal Health and Co-Program Leader of the Comparative Oncology Program.

"UC Davis is a Comprehensive Cancer Center, which is a designation given out by the National Cancer Institute (NCI) to select human cancer centers around the country," Dr. Kent says. "The Comparative Oncology Program is part of that as one of its science programs, and one of our goals is to see what we can learn in animals to help advance human cancer treatment."

The veterinary program puts an emphasis on translational research and offers pathway programs to encourage students to pursue oncology research.
"Through our DVM Ph. D program, students can receive an Institutional National Research Award from the NIH, which supports those building a career in comparative oncology," Kent says. "We train residents in medical oncology, radiation oncology, and surgical oncology, as well as related fields such as dental and oral surgery and neurology. The different services all work together to provide comprehensive patient care. We also work closely with our diagnostic imaging people at our All Species Imaging Center."

The All Species Imaging Center was established in September 2025 and is located adjacent to the UC Davis William R. Pritchard Veterinary Medical Teaching Hospital (VMTH). It includes four diagnostic imaging suites, two control rooms, a patient holding room, a radiologist's interpreting room, and office space for technical staff. The four imaging suites are dedicated to small animal computed tomography, high-field magnetic resonance imaging for both small and large animals, positron emission tomography/CT for both small and large animals, and a dedicated large bore equine CT.

"With these advanced scanners, we have been able to image areas of animals that we had never been able to scan before, such as the lumbar spine of horses and cows, the pelvis and stifles of horses, a full equine cervical spine, and the abdomen of a llama," says Mathieu Spriet, director of Imaging Services at the VMTH, in a release.²

The All Species Imaging Center is a major step forward, but the addition of state-of-the-art diagnostic technology began years earlier. In 2018, for example, the VMTH received a new PET/CT scanner, the Mini Explorer II. Designed to provide veterinarians with both anatomic and physiologic information, it reduces scan time as a result of a wider PET detector. Added benefits include shorter anesthesia time and a reduced injectable dose of radiopharmaceutical needed to acquire images.

"Imaging equipment is extremely important because it is used by every service in the hospital," says Jessica Lawrence, DVM, DACVIM (Oncology), DACVR (Radiation Oncology), DECVDI (Radiation Oncology), professor, Radiation Oncology. "Our thinking has been, what's best for the patient? How can we treat more patients? How do we make this less stressful for large species like horses? We're trying to get the best images possible, but with the best approaches for our patients."

Advanced equipment means little without a dedicated staff, and Kent and Lawrence are the first to acknowledge the importance of all who work at the Comparative Cancer Center.

"Equipment is important, but people more so," Lawrence says. "It's really the combination of advanced equipment and the facilities, as well as funding for their research, that attracts and retains top talent."

Indeed, research plays an essential role at the Comparative Cancer Center. Recent studies include:

• An exploration of alternative methods of administering gemcitabine in dogs that were having success in human medicine. Gemcitabine is FDA-approved for human use in the treatment of aggressive cancers but is relatively unexplored in veterinary medicine. Research in humans suggested longer fixed-dose-rate infusions are more effective than the quicker injections used in veterinary medicine. Evangelia Makrygiannis, DVM, DACVIM (Oncology), investigated 36 dogs treated with gemcitabine infusions at UC Davis between 2013 and 2022 and found that the longer fixed-dose regimen was well tolerated, with 25 percent of subjects achieving partial remission and three percent maintaining stable disease.
• Another study is looking into whether a dog's immune system can be tapped to battle metastatic cancer. 10 dogs have been enrolled in a program exploring the safety and efficacy of a novel canine PDL1 antibody, aiming to optimize dosing while evaluating the antibody's potential to improve survival outcomes in dogs with carcinomas or melanomas that have spread to the lungs.
• A third study, published in the journal GeroScience,³ looked at the role of genetics in the high cancer risk seen among golden retrievers. Its goal: locate genes associated with longer life. It found variants of the gene HER4, long known to be important in human cancers, were also associated with an increased lifespan of almost two years.

The UC Davis Comparative Cancer Center can see more veterinary oncology patients and diagnose them more effectively than ever before, but what does the future hold?

"I would like to continue our growth and build on our training," says Kent. "The DVM students who come through are going to be the next frontline practitioners, as well as the cancer specialists of the future, and that includes basic science, fundamental science, translational science, and clinicians. I want us to expand our ability to sponsor clinical trials and translational research, as well as basic fundamental science research, and build out what is truly the most comprehensive cancer program anywhere. That's how I see us moving forward."

Don Vaughan is an award-winning writer who frequently writes about veterinary topics. His work has appeared in Writer's Digest, The Saturday Evening Post, Cure Magazine, and Encyclopedia Britannica.

Reference

1. https://ccah.vetmed.ucdavis.edu/sites/g/files/dgvnsk4586/files/media/documents/CCAH_Update_Newsletter_Fall_25_Web.pdf
2. https://www.vetmed.ucdavis.edu/news/uc-davis-opens-all-species-imaging-center
3. A variant in the 5' UTR of ERBB4 is associated with lifespan in Golden Retrievers Geroscience 2024 Jun;46(3):2849-2862. doi: 10.1007/s11357-023-00968-2. Epub 2023 Oct 19.