Carbon dioxide laser photoablation adjunctive therapy following superficial lamellar keratectomy and bulbar conjunctivectomy for the treatment of corneolimbal squamous cell carcinoma in horses: a review of 24 cases

Objective To determine the complications and nonrecurrence rates following superficial lamellar keratectomy, bulbar conjunctivectomy, and adjunctive carbon dioxide (CO2) photoablation for corneolimbal squamous cell carcinoma (SCC) in the horse. Study design Retrospective study. Sample population Twenty-four horses with corneolimbal SCC. Procedure Medical records of horses diagnosed with corneolimbal SCC that was surgically excised and where CO2 photoablation was used as an adjunctive therapy from 2000 to 2007 were reviewed. Signalment, prior therapy, tumor location and size, complications, and recurrence of SCC were recorded. Results The Thoroughbred was the most commonly (25%) represented breed. Lesions were >10 mm in diameter in 70.8% of cases. Eight horses (33.3%) had neoplastic cells extending to the deep margin of the keratectomy. All horses were available for follow-up for an average +/- standard deviation of 40.7 +/- 25 months. Four horses (16.7%) developed a recurrence of SCC. Three of these four horses underwent repeat keratectomy and CO2 photoablation, one each, at 4 months, 1, and 2 years following the initial procedure. One horse underwent enucleation 8 months following the initial procedure. Conclusions and clinical relevance As an adjunctive therapy, CO2 photoablation was successful in 87.5% of the horses following a single procedure and in a total of 91.7% following a second therapeutic application. CO2 photoablation appears to be effective as an adjunctive therapy following removal of large corneolimbal SCC in the horse and in cases in which all tumor cells were not excised.