The use of piroxicam as an adjuntive treatment for squamous cell carcinoma in the third eyelid of a horse

The aim of this study was to evaluate the use of piroxicam as an adjuntive treatment for squamous cell carcinoma in a horse. In September 2007, a 10-year-old Thoroughbred gelding weighing 555 kg was seen by private ophthalmologist for showing abundant mucoid secretion, conjunctival hyperemia and granulation tissue on the third eyelid of the left eye. The patient was initially treated with antibiotics and anti-inflammatory drugs. A biopsy of the granulation tissue on the third eyelid was taken. The laboratory reported a non tumoral epithelial hiperplasia. After ten days of treatment, the size of the tumor slightly decreased, but after two weeks the horse showed no further improvement, so surgical treatment was elected. The third eyelid of the left eye was excised completely and the tumor was submitted for histopathological examination. The laboratory reported a squamous cell carcinoma. Postsurgical treatment included topical antibiotics and anti-inflammatory drugs, and piroxicam (80 mg PO SID). Ten months after surgery was performed, the horse showed no complications or signs of recurrence. Squamous cell carcinoma has been reported as the second most common tumor in horses. Non-steroidal anti-inflammatory drugs are potent inhibitors of the cyclooxygenases (COX). It has been demonstrated that COX-2 is overexpressed in several epithelial tumors; therefore, inhibitors of COX-2 can induce apoptosis of tumor cells and inhibit angiogenesis..