Intraoperative Radiotherapy

Cooper is a ten-year-old Boxer who loves his family of raggedy, stuffed animals. He visits them every day, and tells them what is happening in his world. “He’s a riot,” says owner Nora LaBrocca. “He barks at his toys and tells them how the day is going.”

LaBrocca got Cooper when he was eight weeks old and describes him as a ‘dream dog’. “He doesn’t chew; he never had an accident; and he’s magic with people. Everyone loves him,” she says.

Last summer, LaBrocca found some blood on Cooper’s bed and checked him over. When she looked in his mouth, she found a bad tooth, so she took him to her veterinarian. After removing the tooth, Dr. Kevin Starnes was concerned that the gum wasn’t healing properly, so he sent a tissue sample to the OSU Veterinary Diagnostic Laboratory. The result was bad news: squamous cell carcinoma.

Dr. Starnes suggested LaBrocca take Cooper to the Oncology Service at the OSU Veterinary Teaching Hospital (VTH). Veterinary oncologist Shay Bracha confirmed that Cooper had a tumor in his upper jaw. Because the cancer was malignant, Dr. Bracha knew that Cooper’s best chance for survival would be to remove the tumor with a margin of 2 centimeters of surrounding tissue.  Unfortunately, that would require partial removal of the jaw itself. After describing this option to Cooper’s mom, she sadly decided not to proceed. “I thought I was saying ‘Goodbye’,” says La Brocca.

Stan Stearns founded the Gabriel Institute after his beloved Saint Bernard, Gabriel, died while being treated for osteosarcoma. The goal of the Gabriel Institute is to save both dogs and humans through support of cancer research. Fortunately for Cooper, one month before his diagnosis, the Gabriel Institute donated a $500,000 Intraoperative Radiotherapy System to the OSU Veterinary Teaching Hospital. It is the only system of its kind available at a veterinary hospital.

Conventional radiation treatment for tumors occurs post-surgery, and is administered through the skin over a period of many weeks. The Intraoperative Radiotherapy System provides one precise dose of radiation to a tumor cavity during surgery. The dose is created by accelerating electrons through a tube, onto a gold target where low-energy x-rays are generated and emitted evenly in all directions. Then the surgeon closes the incision.

The advantages of the system are fairly obvious: A much shorter treatment span of lower dose radiation to the area most likely to contain remaining cancer cells, while sparing healthy tissue from side effects.

Intraoperative radiation treatment has been used for several years in humans, primarily in the treatment of breast cancer. But there is a big payoff, for both humans and animals, in using a new therapy in a veterinary setting: animals respond more quickly. “We will learn a lot from these veterinary cases,” say Medical Physicist Kristina Tack, who set up the system. “Animals have shorter lifespans, and disease progression moves forward at a more rapid pace, so you can evaluate efficacy after only one year. Humans are not considered cured for five years.”

Collaboration between human and animal medicine is becoming more common, and the Intraoperative Radiotherapy System at OSU is a case in point. Every time the veterinary hospital uses the system to treat an animal, a board-certified Medical Physicist is required to be in the surgery suite to calculate dosage, accurately calibrate the device, and ensure the safety of staff and patient. Dr. Elizabeth Shiner, from Good Samaritan Hospital in Corvallis, has been an integral member of the OSU team.

“In all the ways that really count – safety, precision, and care – I don’t differentiate between my human and non-human patients.” says Shiner. “They both deserve quality care and my best effort.”

Shiner has found her collaboration with OSU to be both challenging and exciting. “The primary use of this device in the human setting has been for breast cancer treatment. We [the VTH] are treating a wide range of sites – to date, all of our cases have been in the oral or nasal cavity. This requires some out-of-the-box dose schemes, and design of custom shielding. We are truly blazing a new trail with our innovative use of this technology.”

So far, six patients, including a horse and a cat, have received intraoperative radiotherapy with good initial results. Cooper is nearly four months post-surgery and doing great. “We are so happy,” says La Brocca. “He could be gone right now, but instead he plays, barks, and bosses the family. He’s just a big love machine.”

New treatment of animals with cancer will provide information that can save human lives too.