Progress Continues in the Development of a New Treatment for Canine Bone Cancer

Osteosarcoma is the most common primary bone cancer diagnosed in dogs, usually affecting the limbs of large and giant-breed dogs and mixed breeds. Unfortunately, cancer spread to the lungs (metastasis) is common with this disease. Recommended treatment involves removing the tumor by amputating the affected limb or use of limb-sparing surgical techniques followed by chemotherapy.

These procedures do have high complication rates, and surgery may not be an option for dogs with additional health problems.

Histotripsy appears to be a well-tolerated and effective treatment for canine bone cancer.

With funding from the AKC Canine Health Foundation (CHF), investigators at Virginia-Maryland College of Veterinary Medicine are studying a new, non-surgical treatment option for canine osteosarcoma known as histotripsy. This treatment uses ultrasound waves to break-up tumor tissue in a precise location without heating up the tissues or causing harm to surrounding normal structures like skin, muscle, or nerves. Progress continues in developing this promising new treatment.

After designing and constructing a custom histotripsy treatment system for dogs, investigators tested it on bone tumor samples removed from client-owned dogs. Treatment in this study successfully disintegrated the tumor tissue without damaging surrounding skin or muscle.

Next, they completed a clinical trial, performing histotripsy on five client-owned dogs with suspected osteosarcoma. Participants received the experimental treatment followed by standard limb amputation. Real-time monitoring and post-operative microscopic examination of the tissues showed that histotripsy again destroyed the target tissue without affecting surrounding tissues. Participating dogs had no significant adverse effects during or after histotripsy.

One promising finding from these studies is that histotripsy can destroy tumor tissues of varied composition. Even though bone tumors are made of differing amounts of mineralized and softer tissues, histotripsy appears able to adequately destroy the tumor.

Even though bone tumors are made of differing amounts of mineralized and softer tissues, histotripsy appears able to adequately destroy the tumor.

There are still many questions to answer about histotripsy:

• Which imaging techniques work best for real-time treatment monitoring and assessing the response to treatment?
• What is the optimal histotripsy dose?
• What is the long-term safety and efficacy of this treatment?
• And finally, how does the immune system respond to tumor destruction by histotripsy—is it primed to fight cancer cells that have spread elsewhere in the body?

CHF and its donors remain committed to answering these questions to develop a non-invasive treatment option for canine bone cancer. Thus far, histotripsy appears to be a well-tolerated and effective treatment for canine osteosarcoma.

Learn more about CHF-funded canine bone cancer research at: akcchf.org/osteosarcomaRPA