Hyperthermia for treatment of ocular squamous cell tumors in cattle.

Fifty-six benign ocular squamous cell tumors and 20 squamous cell carcinomas were subjected to hyperthermia (50 C for 30 sec/cm2 of tumor surface) created by radio-frequency current from an electrothermal device. Of the 76 tumors, 60 (49 benign and 11 malignant) regressed completely following a single treatment. Among the remaining 16 tumors, 7 benign tumors and 2 squamous cell carcinomas regressed completely following a second treatment, whereas 5 carcinomas regressed partially and 2 carcinomas failed to respond after the second treatment, whereas 5 carcinomas regressed partially and 2 carcinomas failed to respond after the second treatment. Thus, 90.8% of the tumors regressed completely, and all of these sites were free of visible lesions 5 1/2 months after the initial treatment. Of 69 sites that were tumor-free at 5 1/2 months, 42 were available for observation at 1 year; all 42 sites were free of tumor. Squamous cell tumors developed subsequently at other ocular or adnexa