When Kitty Smith, of Christiansburg, Virginia, learned her 9-year-old cocker spaniel, Maddi Lynn Grace, had been diagnosed with a soft tissue sarcoma on her left front leg earlier this year, she knew right away that she would take her beloved companion to the Virginia-Maryland College of Veterinary Medicine at Virginia Tech for treatment.
Smith's swift decision was informed by prior experience with the high-quality specialty care at the college’s Veterinary Teaching Hospital.
During her initial visit with a veterinary oncologist at the hospital, Smith learned of a new clinical research study investigating focused ultrasound therapy in the treatment of dogs diagnosed with solid tumors. She was offered the opportunity to enroll Maddi as the first patient in the study. After talking it over with her family, Smith decided to sign up and in late March, Maddi underwent treatment.
“I wanted whatever needed to happen to save her life at that point,” said Smith, who first brought Maddi home at 6 weeks old. “I felt so fortunate that my Maddi was chosen to be the first dog treated in the study. It made me so happy to know that she may be helping other dogs with this disease and also that the treatment may be used to help humans.”
Now, a few weeks after treatment, Maddi’s follow-up appointments have indicated that she is cancer-free.
Through the one-year study, funded by the Focused Ultrasound Foundation, veterinary researchers hope to determine whether high-intensity focused ultrasound (HIFU) — a technology that uses ultrasonic energy guided by real-time imaging to treat tissue without incisions or radiation — can effectively stimulate an anti-tumor immune response in dogs. The technology has been used successfully in humans, and now the college is one of the first two U.S. veterinary schools partnering with the foundation to test it in dogs.
“Because many types of tumors that affect people also occur naturally in dogs, focused ultrasound could not only augment the traditional approach to cancer in dogs but also advance our understanding of human cancer,” said Jeffrey Ruth, clinical assistant professor of radiology, who is leading the study.
“Traditionally, animals have served as models in comparative studies before expanding innovative therapies to human trials,” said Neal F. Kassell, a physician who is chairman of the Focused Ultrasound Foundation. “With the foundation’s new veterinary program, we are starting a virtuous cycle where veterinarians will have new, innovative therapies to offer clients, and we can apply the experience obtained using focused ultrasound in pets to accelerate the adoption of the technology for human applications.”
Solid tumors, including soft tissue sarcomas, carcinomas, and mast cell tumors, are some of the most common tumors in dogs. While surgery is the standard and most effective therapy, complete tumor removal is not always possible and depends on tumor size and location. In this situation, other options include limb amputation, radiation therapy, and chemotherapy. Because of the limitations and potential side effects of these treatments, immunotherapy — treatment that stimulates a patient's own immune system to fight cancer — is an active area of research.
“These canine tumors tend to occur on the limbs and may recur if they are not entirely removed. As a result, often amputation is required,” said Ruth. “It is our hope that focused ultrasound will add to current treatment options by providing a way to non-invasively destroy tumors and to disrupt tumor cell membranes and stimulate a dog’s own immune system to fight the cancer.”
Standard treatment procedures for solid tumors include bloodwork, a CT scan, and surgery. “For dogs enrolled in the study, in addition to receiving the standard treatment, they will also have the ultrasound treatment of the tumor a few days before surgery,” said Ruth. “When the tumor is removed, we examine it to see if there was an influx of white blood cells, which would indicate ultrasound was successful in stimulating the patient’s own immune response.”
Other comparative oncology studies — those involving naturally occurring cancers in veterinary patients to advance the diagnosis and treatment of cancer in pets and people — underway at the college are exploring immunotherapy in the treatment of spontaneous brain tumors (gliomas) and liver tumors in dogs.
In addition to principal investigator Ruth, other veterinary college investigators on the HIFU study team include co-principal investigators Nick Dervisis, assistant professor of oncology; Irving Coy Allen, assistant professor of inflammatory disease; Gregory Daniel, interim dean of the college and professor of radiology; Otto Lanz, professor of small animal surgery; and Kevin Lahmers, associate professor of anatomic pathology.