A better solution? Human cancer treatment used to eliminate sarcoids in horses
Ultrasound technique histotripsy has already been used on one mare in the US
A technique using ultrasound to destroy tumours that has been effective in people with cancer has been used to treat equine sarcoids.
The Virginia-Maryland College of Veterinary Medicine in the US has been conducting a live clinical trial using histotripsy.
The technique uses focused ultrasound waves to a targeted area. This creates microscopic “bubble clouds” from gases in tumour tissues; the bubbles form and collapse in microseconds, creating forces that destroy cancer cells.
Virginia Tech biomedical engineer Eli Vlaisavljevich’s lab has been refining it to target human liver, kidney and pancreatic tumours, and colleague Joanne Tuohy in the veterinary college has been using it to treat cancer in dogs.
Sophie Bogers, assistant professor of large animal surgery at the college, said horses seemed the obvious next step.
“There is no ‘one-fix-for-all’ solution for sarcoids,” she said. “Many of them require chemotherapy or invasive surgery. But I want a better solution.”
Histotripsy adapted for horses
Engineers and vets have been working together on a wearable device that could allow horses to be treated with histotripsy.
Never miss out on the latest happenings in the equestrian world
“This spring, their system got its first real test, on a horse named Pea, a nine-year-old Hanoverian mare who had a tumor on her belly,” a spokesperson for Virginia Tech said.
“Pea’s case was the first live test in the Virginia-Maryland College of Veterinary Medicine clinical trial trying to answer whether this sound-wave technology could treat sarcoids, the most common and hardest-to-beat skin tumor in horses.
“Researchers don’t yet know whether histotripsy can reliably keep a sarcoid from coming back, but they do know that at least one horse can tolerate the treatment standing and awake [under sedation], with no apparent ill effects.”
Pea is owned by Kelly Kuykendall, whose vet noticed the sarcoid and looked into pricing for surgical removal.
“Somehow it circled around to, oh my gosh, we have this study,” Kelly said. “My vet called me back within a couple of hours and said: ‘I’ve got great news. If you want to participate in a study, you can get this whole thing removed for free’.
“It’s super cool we get to help advance science and try to be at the top of new technologies.”
Kelly drove Pea from North Carolina; the mare stayed overnight and the team removed the sarcoid the next morning. By lunchtime she was on her way home.
“Everything was easy peasy,” said Kelly, who had not realised Pea would be the first horse treated while conscious.
“I said ‘That’s incredible’,” she said. “I wasn’t worried about that, just thrilled. I think it’s so cool we’re the first people coming in to do this.”
Destruction of the tumour was confirmed, which was “an early, encouraging sign, but not yet full proof the treatment works”. The team is now looking for more horses for this phase of the study.
Dr Bogers noted that sarcoids are the most common skin tumour in horses, notoriously hard to eliminate.
“In some cases for large sarcoids, people find the management of the sarcoid becomes too much, and they elect euthanasia,” she said.
“Fibroblastic sarcoid is basically a fleshy mass that horses get on their skin. The worst look like big red blobs. Left alone, they ulcerate, bleed, and attract flies.”
She pointed out that ultrasound is a tool vets use on horses “all the time”, and are comfortable with. She wants to produce a device small enough to be carried with vets and used the day a sarcoid is found, rather than months later.
“The more horses that have sarcoids treated early, the less management problem they’ll be, and the less morbidity from having these big lesions,” she said.
● To stay up to date with the latest equestrian news, subscribe to the Horse & Hound website
Eleanor is an experienced journalist who spent over eight years working for local and national newspapers before joining H&H as news editor in March 2016. Passionate about equine welfare and exposing the truth, Eleanor has reported on all aspects of the industry, from Brexit to anti-bullying campaigns, and from dressage rules to mules. Her sport of choice is showjumping, in which she competes her own horses, and she also enjoys reporting at local jumping shows through to international championships.