The University of Wisconsin School of Medicine and Public Health (UWSMPH) Department of Medical Physics has partnered with the UW School of Veterinary Medicine (UWSVM) to launch a first-of-its-kind study of FLASH radiation therapy efficacy in pet dogs with osteosarcoma, an aggressive bone cancer that commonly leads to leg amputation.
The trial was designed collaboratively by Nate Van Asselt, DVM (UWSVM Radiation Oncology), Professors Brian Pogue (Medical Physics) and Albert Van der Kogel (Human Oncology), and doctoral student William Thomas (Medical Physics). It also has additional support in veterinary care and radiation dosimetry through several other staff and faculty in both schools.
The goal is to assess if FLASH treatment spares normal tissue more than conventional radiation treatment. Many studies, including those at UW—Madison, have shown that FLASH treatment in mice can reduce skin damage from radiation while allowing for equivalent tumor damage.
Patient dogs for this trial are recruited when they present with limb osteosarcoma, and they are randomized into the study to receive either conventional or FLASH radiotherapy. Osteosarcoma is a highly aggressive cancer of the bone, common in medium to large dogs, usually leading to amputation of the leg to minimize further spread of the disease. The trial is recruiting dogs from across Wisconsin through a referral system, and all treatments are provided for free to the owners for this study.
For this study, the team is using a specially designed FLASH linear accelerator located in the Medical Sciences Center, with careful radiation dose measurement and system commissioning by medical physics students and staff. FLASH treatment is achieved by ultra-high dose rate irradiation, where the radiation is delivered over 1000x faster than in conventional radiation therapy.
FLASH radiotherapy has been the topic of interest in many radiotherapy centers worldwide over the past decade, but to date no center has done a prospective randomized study testing the efficacy of normal tissue sparing in large animals or humans. There have been safety trials of humans and veterinary animals, but head-to-head randomized trials have not occurred yet. The goal of this study is to determine if the sparing seen in mice and rat studies translates to higher-order species. A positive finding could be a critical step towards human translation.
Funding for this work has come from the UW Carbone Cancer Center and the National Cancer Institute, along with a research partnership loan of linac use from IntraOp Medical, Inc.
Contact: Catherine Showers – cnshowers@wisc.edu