Radiation therapy of ceruminous gland carcinomas in dogs and cats

Nine dogs and 9 cats with ceruminous gland carcinoma were evaluated to determine whether they would receive radiation therapy. Tissue samples were reviewed to confirm the diagnosis and to assess completeness of resection in animals that had undergone surgery. Seven animals were excluded because surgical excision was determined histologically to have been complete (5) or because the owners did not wish to pursue treatment, because of advanced disease (2). The remaining 6 cats and 5 dogs, 6 of which had previously undergone surgery, were included in the study. The radiation therapy dose was 48 Gy, given in 12 fractions over 4 weeks. The product-limit estimate of mean progression-free survival time was 39.5 months. The estimate of 1-year progression-free survival rate was 56%. The tumor recurred in 4 animals, and metastases were observed in 3 animals. Radiation therapy was found to be safe and effective.