Treatment of bovine and equine ocular squamous cell carcinoma by radiofrequency hyperthermia.

Forty-five ocular squamous cell carcinomas (SCC) in 17 cattle and 8 horses were treated by radiofrequency hyperthermia, resulting in 80% complete regression and 16% partial regression. Tumors were histologically diagnosed as SCC; 50% of the tumors were recurrent, having been treated previously by surgery, cryosurgery, radiation, or immunotherapy. After hyperthermic treatment, most animals were available for tumor measurement at 4 to 6 weeks and at 8 to 16 weeks, with a final observation period of 2 to 10 months for all. Complete regression occurred in 8 of 12 tumors given a second hyperthermic treatment. It was concluded that hyperthermia is an effective and easily applied treatment modality for ocular SCC in cattle and horses; however, it cannot be recommended for large tumors (larger than equal to 5 cm diameter) that have deep eyelid or conjunctival penetration.