Laser Surgery as A Sole Treatment of Histologically Confirmed Equine Sarcoids: Outcome and Risk Factors for Recurrence

Abstract

AimsTo evaluate laser surgery as a sole treatment for sarcoid resection; and determine risk factors for recurrence.MethodsHorses included had diode laser surgery to remove ≥1 sarcoid. No previous/concurrent veterinary treatment was administered. Diagnosis was confirmed by histology in all cases. Clinical data were retrieved from the hospital database. Follow‐up information was obtained by telephone questionnaire.ResultsFollow‐up data are currently available for 290 sarcoids, in 73 horses, over 177 horse‐years. Overall recurrence rate was 1.31 sarcoids per 10 horse‐years (95% CI 0.80–2.02). For horses with 1–5 sarcoids, recurrence rate was 0.95 sarcoids per 10 horse‐years (95% CI 0.52–1.62). For each additional sarcoid removed, that horse was 1.24 (odds ratio) as likely to have at least one sarcoid recur (95% CI 1.03–1.50; P<0.001). Initial univariable analyses on this preliminary dataset revealed no risk associated with age, breed, sarcoid location (grouped as lower limb; upper limb/ventral abdomen; body; head and neck), sarcoid size or month of removal (all P>0.05). Horses with mixed‐type sarcoids were more likely to have recurrence than horses with sarcoids of other types (P = 0.007). Time‐to‐recurrence (mean 7.6 months, 99% CI 3.2–11.9) was significantly shorter than follow‐up time for horses without recurrence (mean 30.0 months, 99% CI 19.8–32.1; P<0.001).ConclusionsIf a horse has 5 or less sarcoids removed by laser surgery alone, recurrence will occur in <1 horse every 10 horse‐years. Risk factors for recurrence include number of sarcoids and mixed‐type sarcoid. Recurrence is most likely within 12 months of original surgery. Full time‐to‐event regression analysis is intended.Practical significanceThese preliminary findings indicate laser removal of sarcoids as a sole treatment method carries a high success rate. These results provide evidence‐based support for decision making in equine practice, where sarcoids are the most commonly encountered skin tumour.Ethical animal researchNot required by this Congress: retrospective clinical study. Sources of funding: Polly Compston is supported by the Margaret Giffen Trust. Competing interests: None.