Breakthrough in Equine Sarcoid Treatment: Focused Ultrasound Technology

Veterinary researchers at Virginia Tech are making strides in treating sarcoids—the most prevalent and challenging skin tumors in horses—through a novel application of focused ultrasound technology known as histotripsy. This collaborative effort between biomedical engineering and veterinary medicine could reshape the treatment possibilities for equine patients.

Dr. Sophie Bogers, an assistant professor of large animal surgery at the Virginia-Maryland College of Veterinary Medicine, emphasizes there's no one-size-fits-all method for tackling sarcoids, an issue that often leads to invasive procedures or chemotherapy. “We need a better solution,” she asserts, highlighting the urgency for more effective treatment options.

At Virginia Tech, Eli Vlaisavljevich’s lab is pioneering histotripsy, which employs focused ultrasound to generate a bubble cloud that disrupts tumor tissues. Their joint project with veterinarians aims to design a device tailored for safe application on horses. A significant test occurred recently with a 9-year-old Hanoverian mare named Pea, who responded well to the treatment.

A Persistent Challenge for Horse Owners

Sarcoids can be particularly frustrating for horse owners, as recurrent tumors can appear in delicate areas like the eyelid or girth, leading to extensive management issues that may include multiple surgeries and costly care over years. Dr. Bogers notes that in severe cases, owners have even considered euthanasia due to the overwhelming burden these tumors can produce.

These tumors arise when the bovine papillomavirus interacts with a horse's genetic predisposition, resulting in various forms, including the described fibroblastic sarcoid, which can manifest as unsightly lesions. Standard treatments often require surgical removal complemented by chemotherapy; however, the location and size of certain sarcoids make them difficult to treat effectively.

The Role of Ultrasound in Treatment

The histotripsy technique has its roots in human medicine, developed at the University of Michigan before making its way to Virginia Tech, where it has received recognition as one of the Focused Ultrasound Centers of Excellence globally. Dr. Joanne Tuohy, a surgical oncology professor, brings her experience with histotripsy in treating canine cancers into the equine sphere, making it a logical target for further exploration.

Equine veterinarians are already well-versed in ultrasound technology, which adds an extra level of comfort for practitioners looking to adapt this procedure for horses. Dr. Bogers envisions a portable device that could be brought directly to the horse as soon as a sarcoid is detected, transforming the current approach that often leads to delays. “Prompt treatment may reduce the chances of complications and enhance overall animal welfare,” she states.

To adapt histotripsy for horse use, the research team has innovated a solid coupling pad designed to transfer sound waves effectively to a standing horse, overcoming challenges presented by conventional methods that require water baths.

Pea's Pioneering Treatment

Pea came into the study unexpectedly when her owner, Kelly Kuykendall, learned of the clinical trial through her veterinarian. “It was fortunate timing,” Kuykendall recalls. Pea's tumor required immediate attention, and enrollment in the trial offered an opportunity for treatment without the cost burden typically associated with surgical procedures.

After traveling from North Carolina for the treatment, Pea underwent histotripsy while awake, an unprecedented step in this study. “I was amazed to learn Pea was the first horse to be treated in this manner,” Kuykendall shared, expressing her excitement about contributing to the advancement of veterinary science.

Dr. Bogers confirmed that the team was able to successfully excise the tumor and utilize both handheld and robotic systems to verify treatment effectiveness.

Next Steps in the Research

The initial outcomes from Pea's case are encouraging; however, Dr. Bogers remains cautious, requiring the participation of four additional horses to solidify these findings. She actively invites veterinarians to collaborate in identifying suitable candidates for the trial. “We're open to traveling to collaborate on-site for training in the surgical techniques in exchange for access to tumor specimens for research,” she expressed.

Reflecting on her experience, Kuykendall urges other horse owners to act quickly when discovering sarcoids. “Participating in this study is mutually beneficial, enhancing the lives of horses while pushing veterinary knowledge forward,” she said, emphasizing the win-win nature of such initiatives.

Enrollment and Eligibility for the Trial

Horses may qualify for enrollment in the trial if:

• They present with a fibroblastic or nodular-type sarcoid (not occult/flat); and
• They have not received treatment within the past six months or have a recurring sarcoid post-treatment.

Compensation could cover consults, surgical fees, and up to $1,500 in hospital costs. Horses that do not qualify for the live treatment option may still be considered for an ex vivo analysis, where tumor tissue is removed for research instead.

For more information and potential enrollment, contact Large Animal Services at the Veterinary Teaching Hospital via phone at 540-231-4621, and be prepared to provide photographs detailing the tumor's location on the horse's body.