Editor's Note: This article is part of TheHorse.com's ongoing coverage of topics presented at the British Equine Veterinary Association's 51st annual Congress, held Sept. 12-15 in Birmingham, U.K.
Canker, a destructive inflammatory disease of the hoof that generally originates in the frog, has always frustrated treating veterinarians. Typical treatments include superficial debridement, topical therapies such as the antimicrobial drug metronidazole, and good hygiene. However, because canker tends to recur, Veronika Apprich, DVM, from the Large Animal Surgery and Orthopedics department at the University of Veterinary Medicine in Vienna, Austria, and colleagues evaluated a new treatment method aimed at reducing hospitalization time and recurrence rate in affected horses. They presented their findings at the British Equine Veterinary Association's 51st annual Congress, held Sept. 12-15 in Birmingham, UK.
Although canker's etiology is still not clear, Apprich cites a recently published study (Brandt 2010) describing certain similarities between canker and equine sarcoids. In this study 25 horses diagnosed with canker also tested positive for bovine papillomavirus DNA, which can lead to sarcoid development. Based on these results, Apprich proposed a new and promising therapy option for canker: the common sarcoid treatment topical cisplatin chemotherapy.
To evaluate its effectiveness, Apprich treated three horses hospitalized at her clinic for canker first with surgical debridement of the canker tissue, then with the cisplatin chemotherapy two to three days later. She and colleagues continued to administer this topical treatment 10 times per day, every other day, until the surgical wounds were superficially keratinized (the outer, horny layer of the skin forms). In one horse the surgeon had to resect a small amount of recurring canker tissue after the fifth cisplatin administration. All three horses were discharged within two weeks after chemotherapy concluded.
During the seven- to 14-month follow-up period, only one horse developed a small recurrence of canker in one of his front hooves; the other two horses are currently relapse-free and have shown no side effects from the cisplatin.
"By now we have treated eight horses with this therapy, and one major advantage we see is a clear reduction in the hospitalization period (which previously was up to two to three months)," Apprich noted. "It also seems to be a safe and cost-efficient therapy compared to other treatment options, and in contrast to other treatments we see almost no recurrence during the healing period and a very low tendency to recur in the follow-up period."
She cautioned, however, that practitioners must take strict precautions with cisplatin to avoid skin and eye contact, and during treatment horses should be kept isolated from other patients. "So this therapy is only viable in a hospital setting," she said.
Also, similar to sarcoids, treatment efficacy appears to be lower for larger affected areas and horses that had previously undergone intensive treatment.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.