Texas A&M performs first-ever stereotactic body radiation therapy on a bear
Judge Sue “Lady” Sloan, one of Baylor University’s two live animal mascots, is the first American black bear to be treated with stereotactic body radiation therapy using the TomoTherapy system.
When a benign mass called a thymoma was found in Lady’s chest in summer 2019, veterinary specialists at Texas A&M College of Veterinary Medicine & Biomedical Sciences’ (CVM’s) Veterinary Medical Teaching Hospital (VMTH) teamed up to deliver a course of treatment found at only one other veterinary school in the U.S.
This treatment, which uses many beams of high-energy photons to deliver large doses of radiation to the tumor and spare surrounding tissues, has the potential to stop the tumor’s growth while also preserving the bear’s quality of life.
“The good news for Lady is that she’s completely asymptomatic; she has no clinical signs of the mass, which means that we caught it early,” said Dr. Lauren Smith, the CVM’s clinical assistant professor and radiation oncologist.
“Early detection is key with cancer. Being able to intervene at an early point is why we have a very positive outlook for her.”
Lady was diagnosed during a routine checkup with CVM’s professor emerita Dr. Sharman Hoppes. Only two other cases of thymomas in bears exist in veterinary literature.
When plans for treatment began, Dr. J. Jill Heatley, a zoological medicine specialist who joined the case later that summer, recruited Dr. Smith to figure out the best way to deliver precise, effective treatment to Lady’s tumor, which was already larger than a softball.
“What makes TomoTherapy unique is that we treat these tumors in a slice-by-slice fashion. We get millions of opportunities to get a dose into the tumor while avoiding normal tissues; it allows us to have much better and more conformal plans and much tighter doses of distributions to the tumor itself,” said Dr. Smith.
“Where TomoTherapy shines in cancer treatment across the world is treating tumors with complex shapes and geometries. Lady’s tumor is sitting right up in front of the heart and between the lungs, so we’re trying to get really high ablative doses to kill this tumor while it’s sitting in between those fairly sensitive, important structures.”
TomoTherapy offers another benefit in that it has onboard CT imaging capabilities. During Lady’s three doses of treatment, the CT scanner was used to make sure she was in the exact same position every day.
With her radiation complete, Lady will return to her home at the Bill and Eva Williams Bear Habitat in Waco, Tex.
Original story by Megan Myers, Texas A&M College of Veterinary Medicine & Biomedical Science.