Current Concepts in the Treatment of Bovine Ocular Squamous Cell Tumors

Abstract

Usually 10 per cent or fewer of the ocular squamous cell tumors in a Hereford cow herd are true carcinomas. Around 30 per cent of the benign tumors regress spontaneously, and squamous cell carcinomas may arise ab initio without progressing from a grossly visible "precursor" lesion. Differential gross and cytologic features assist in making accurate diagnoses of the disease and determining the treatment. Radiation therapy, immunotherapy, surgery, and, in particular, cryosurgery have been employed successfully in the treatment of bovine ocular squamous cell tumors. RF current-induced hyperthermia is an easily performed, highly effective method for treating small squamous cell tumors, causing regression in over 90 per cent of the cases; surgical removal of similar tumors causes regression in only 46 per cent of the cases. A management protocol for controlling losses due to ocular squamous cell tumors in a Hereford or Simmental cow herd includes: Periodic observation of all susceptible cattle. Hyperthermic treatment of all small tumors; orbital exenteration in cases of large, noninvasive carcinomas on the globe or palpebrae; shipment to slaughter of animals with invasive or metastatic disease. Genetic control through careful record keeping and culling.