Reducing Recurrence in Equine Corneolimbal SCC: Outcomes of Adjunctive Cisplatin Biodegradable Bead Therapy

(1) Context: Squamous cell carcinoma (SCC) is the most prevalent ocular neoplasm in horses, with a reported 45% recurrence rate when managed by surgery alone. (2) Objective: To evaluate the effect of adjunctive cisplatin biodegradable beads (CBBs) on recurrence rates of equine corneolimbal squamous cell carcinoma (SCC) and to document associated adverse effects. (3) Methods: Seventeen cases of histopathologically confirmed corneolimbal SCC in horses were retrospectively identified. Masses were surgically excised by keratectomy and/or conjunctivectomy under general anesthesia, followed by implantation of CBBs beneath conjunctival flaps at approximately 1 cm intervals around the excised area. Horses were monitored through owner follow-ups for up to five years postoperatively. (4) Results: Three horses (17.64%) experienced local mass recurrence within one year of treatment, and one horse (8.33%) relapsed approximately two years post-treatment. Minor local adverse effects-including chemosis (36%), hyperemia (64%), localized yellow discoloration (55%), and granular tissue formation (36%)-resolved within one to two months after surgery. Two horses developed bead-associated uveitis requiring closer ophthalmic monitoring. Vision was preserved in all but one relapsing case. (5) Conclusions: These findings suggest that adjunctive use of cisplatin biodegradable beads during surgical excision of equine corneolimbal SCC may significantly reduce recurrence rates and is generally well tolerated.