Successful definitive radiation treatment of refractory canine oral papillomatosis.

This case report describes a three-year-old male intact border collie diagnosed with canine papillomavirus type 1 (CPV-1+) oral papillomas resistant to standard-of-care. With time, he developed lesions consistent with squamous cell carcinoma. Malignant tumors were incompletely excised and treated with definitive external beam radiation therapy (45 Gy, 3 Gy × 15 daily). The remaining oral cavity received 27 Gy (1.8 Gy x 15 daily) to treat the disseminated oral papillomatosis. A temporary treatment delay of 2 weeks was instituted due to grade 3 mucositis. The patient remained in complete remission after 10 months from radiotherapy. No tumor recurrences were noted by the owners after >1 year from treatment.