A retrospective comparison of surgical removal and subsequent CO2 laser ablation versus topical administration of mitomycin C as therapy for equine corneolimbal squamous cell carcinoma

A retrospective comparison of surgical removal and subsequent CO2 laser ablation versus topical administration of mitomycin C as therapy for equine corneolimbal squamous cell carcinoma:

Abstract

Objective  To compare the complications and nonrecurrence rate following topical mitomycin C (MMC) therapy vs. CO₂ laser ablation for treating equine corneolimbal squamous cell carcinoma (SCC).

Study design  Retrospective study.

Sample population  Twenty-five horses with corneolimbal SCC.

Procedures  Medical records of horses undergoing surgical tumor resection followed by either topical MMC therapy (0.04%) or CO₂ laser ablation between the years of 2004 and 2010 were reviewed. Recurrence and complications were compared between groups and within MMC subgroups defined by the time at which treatment was initiated relative to surgery.

Results  Therapy with topical MMC resulted in a nonrecurrence rate comparable to that achieved with CO₂ laser ablation (82.4% vs. 85.7%, respectively). Initiation of MMC following epithelialization of the surgical site a mean of 15 days postoperatively did not result in increased recurrence rates relative to treatment in the immediate postoperative period. Vision- or globe-threatening complications tended to occur with greater frequency in horses receiving topical MMC in the immediate postoperative period (5 of 6 major complications) relative to following epithelialization of the surgical site (1 of 6 major complications).

Conclusions  Horses receiving adjunctive topical MMC therapy were no more likely to experience tumor recurrence than were horses undergoing CO₂ laser ablation in the horses in this study. Initiation of two to three rounds of MMC following epithelialization of the surgical site results in fewer major complications and achieves comparable disease resolution relative to treatment in the immediate postoperative period.