EVALUATION OF DOGS AND CATS WITH TUMORS OF THE EAR CANAL - 145 CASES (1978-1992)

Objective-To characterize the frequency, clinical signs, biologic beha vior, and response to treatment of tumors of the ear canal in dogs and cats. Design-Retrospective analysis of medical records. Animals-Medic al records of 81 dogs (48 malignant tumors, 33 benign tumors) and 64 c ats (56 malignant tumors, 8 benign tumors). Procedure-Data were analyz ed for cats and dogs with malignant tumors, and risk factors were anal yzed for their potential impact on survival time. Results-Malignant tu mor types most commonly reported included ceruminous gland adenocarcin oma, squamous cell carcinoma, and carcinoma of undetermined origin. Me dian survival time of dogs with malignant aural tumors was > 58 months , whereas that of cats was 11.7 months. A poor prognosis was indicated by extensive tumor involvement (dogs) and by neurologic signs at lime of diagnosis, diagnosis of squamous cell carcinoma or carcinoma of un determined origin, and invasion into lymphatics or blood vessels (cats ). Clinical Implications-Malignant tumors of the ear canal in dogs and cats have a propensity for local invasion, but lend not to metastasiz e. Squamous cell carcinoma and carcinoma of undetermined origin were t he most locally aggressive tumors. Malignant tumors of the ear canal a re best managed by aggressive surgical excision. Radiotherapy may be u seful when tumors cannot be completely removed.