PERIOPERATIVE INTRATUMORAL ADMINISTRATION OF CISPLATIN FOR TREATMENT OF CUTANEOUS TUMORS IN EQUIDAE

Twenty-seven horses (and 1 mule) with 32 histologically confirmed cuta neous tumors were studied to evaluate the effects of intratumoral inje ction of cisplatin initiated at the time of surgery. As a result of su rgery, 9 of the wounds were closed primarily (5 sarcoids, 4 carcinomas ) and 23 were left open to granulate (16 sarcoids, 6 carcinomas, 1 ham artoma). Chemotherapy consisted of 4 treatment sessions of intratumora l injection of cisplatin in purified sesame oil at 2-week intervals. T he first treatment session was administered intraoperatively. A contro lled-release formulation of cisplatin in sesame oil was used to limit drug egress from the injection site. Dosage was 1 mg of cisplatin/ cm( 3) of tissue. The mean relapse-free interval was 41 +/- 3.7 months. Th e estimates of overall relapse-free survival rates were 92 +/- 5% at 1 year and 77 +/- 11% at 4 years. Cisplatin-related local toxicosis was minimal and wound healing war not compromised. Intratumoral injection of cisplatin appears safe and effective when administered in the peri operative period for selected tumours in equidae.