Objective To assess the effectiveness of topical mitomycin C application as an alternative adjunctive therapy to CO2 laser ablation in the treatment of equine ocular squamous cell carcinoma.

Design A retrospective clinical study of eight client owned horses in which 10 affected eyes were treated for ocular squamous cell carcinoma over a 17 month period. (March 2003 to

Procedure Each horse was given a general anaesthetic to allow CO2 laser ablation of the lesion(s). Mitomycin C at a concentration of 0.4 mg/mL was then applied intraoperatively to the affected areas for 1 or 5 minutes. Postoperatively a triple antibiotic eye ointment was applied to the eye twice daily and each horse was treated with systemic non-steroidal anti-inflammatory drugs for 7 days.

Results Recurrence following treatment was noted in three eyes. Two of these were retreated and no further signs developed. The remaining eye was enucleated at the request of the owner. Overall 90% of treated eyes appeared free of tumour a minimum of 11 months post treatment.

Conclusion In this case series mitomycin C appeared to offer a valid alternative to other adjunctive therapies currently employed in the treatment of equine ocular squamous cell carcinoma.