Veterinarians Test New Hoof Cancer Treatment
At first, the veterinarians treated Drami’s hoof lesions as canker—a chronic frog infection. But Drami’s tumors recurred aggressively after each surgical treatment. Referral and subsequent evaluations led to a surprising diagnosis: cancer.

Hoof cancer is rare, but it certainly does occur. In Drami’s case, it was a 5-by-6 cm mass of squamous cell carcinoma (SCC) protruding from the front of a hind hoof, which was constantly bleeding. The 20-year-old mare was lame and depressed, her treating veterinarians said. But after two surgeries and electrochemotherapy, she is now in full remission.

“It’s been challenging, but it’s always such a great emotional feeling and reward to defeat such a terrible disease,” said Enrico Spugnini, DVM, PhD, equine oncologist at Biopulse, in Naples, and Equivet Roma Hospital, in Rome, Italy.

“In terms of welfare, it has been well worth the treatment the mare went through,” he said. “And since there’s such a severe lack of information on cancers in horses, we may also have potentially opened a new field of medical procedures in equine veterinary medicine through this experience.”

After surgical debulking of the tumor under general anesthesia, Spugnini and colleagues administered electrochemotherapy (using the drug bleomycin) directly into the cancer site, during the surgery.

Electrochemotherapy sends permeabilizing electric pulses into tumors or tumor beds while simultaneously administrating a chemotherapeutic agent. Spugnini has already used it to successfully increase chemotherapy’s efficacy on squamous cell carcinomas in cats, he said. He’s also tried it with good results in other nonhoof cancers in horses.

They repeated the surgery with electrochemotherapy one month later and then performed three follow-up monthly sessions of electrochemotherapy alone, Spugnini said. With each treatment, the mare appeared to feel better. A year later, she had marked improvement in both gait and emotional status, with no sign of a recurring tumor.

The few previous cases of squamous cell carcinoma in a hoof that have been reported in scientific journals show poor outcomes, he said. In fact, amputation is sometimes suggested as the best option. But for Drami, who would probably have difficulty adjusting to losing a limb at her advanced age, amputation was not an option.

The new approach combining surgery and electrochemotherapy proved successful and could be a new way to move forward with such cases, says Spugnini. While it might not return a horse to full athletic potential, it can still greatly improve his quality of life.

“The owner, a fellow veterinarian, was deeply attached to this horse and was prepared to find a solution to keep her alive and well,” he said.

The study, “Isolated limb perfusion electrochemotherapy for the treatment of an advanced squamous cell carcinoma of the hoof in a mare,” was published in the Open Veterinary Journal.