INTRALESIONAL SUSTAINED-RELEASE CHEMOTHERAPY WITH THERAPEUTIC IMPLANTS FOR TREATMENT OF CANINE SUN-INDUCED SQUAMOUS-CELL CARCINOMA

Squamous cell carcinoma (SCC) is the most frequently reported malignan t epithelial tumour in dogs. Canine sun-induced SCC represents a usefu l animal model to evaluate new therapeutic modalities for possible hum an applications. We evaluated the safety and efficacy of treating sun- induced SCC in dogs with intralesional sustained-released chemotherape utic gel implants that contained collagen, epinephrine (epi), and eith er 5-fluorouracil (5-FU) or cisplatin (CDDP). Dogs with large, single SCC or fields of multiple SCC were treated with 5-FU/epi gel for a min imum of three weekly injections. Dogs without a complete response were then treated with CDDP/epi gel for a minimum of three weekly treatmen ts. We treated from one to 11 primary, recurrent, or refractory SCC pe r dog (tumour size 0.2-92.4 cm(2); mean cumulative tumour area of 40.7 cm(2) per dog). All dogs had at least 50% reduction in cumulative tum our area after treatment with 5-FU/epi gel. More than half(seven of 13 ) had complete resolution of SCC after treatment with 5-FU/epi gel or CDDP/epi gel. Minimal local tissue reactions were noted; no systemic t oxicity occurred. Sustained-release chemotherapy using intralesional 5 -FU/epi gel and CDDP/epi gel therapeutic implants is effective in trea ting canine sun-induced SCC of the skin.