Squamous cell carcinoma (SCC) is the most common neoplasm, or cancer, of the equine eye. | Photo: Courtesy Dr. Dennis Brooks

There are no guarantees that treatment will circumvent future health issues, particularly when it comes to squamous cell carcinoma (SCC)—the most common ocular neoplasia (tumor) in horses. For many health conditions, veterinarians can use research study data to provide estimates of how likely a horse’s condition will return. But for SCC, that range is wide.

“Studies reported recurrence rates of 25% to 67%,” said Nicole Scherrer, DVM, at the 2018 American Association of Equine Practitioners Convention, held Dec. 1-5 in San Francisco, California. “We didn’t have a good number to give clients.”

Scherrer is a clinical assistant professor of ophthalmology at the University of Pennsylvania School of Veterinary Medicine (Penn Vet) New Bolton Center, in Kennett Square. Seeking to narrow recurrence estimate windows and identify which factors make it more likely, she conducted a retrospective study on 36 horses treated for eyelid SCC at Penn Vet from April 2002 through January 2018