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.