Abstract
We report a combination therapy of volume reduction surgery and postoperative hypofractionated radiotherapy of an osteosarcoma in the nasal cavity of a dog. A6-year-old, castrated Great Pyrenees was brought to our hospital with a main complaint of bleeding from the left nasal cavity.As X-ray examination showed increased impermeability in the left nasal cavity, computed tomography (CT) and biopsy were performed.Histopathologically the disease was diagnosed as an osteosarcorma, and the severity of the disease was classified as T1N0M0 according to the TNM Classification by the WHO, because no distant metastasis was seen.After a volume reduction was surgically performed on day 24, megavoltage radiation therapy was conducted at 36 Gy/6 times/3 weeks. CT of the head and chest performed on days 188 and 259 showed no tumor recurrence or distant metastases to the lung.Necrotic nasal bone fragments were removed on day 416, and a nasal mucosa biopsy was done at the same time.The biopsy revealed recurrence of the osteosarcoma.As infiltration into the caudal side of the left maxillary canine tooth became noticeable, local thermal ablation was performed on day 869.Masses in the lung and spleen, however, were found on day 969, and the dog died on day 1012.The patient had survived for a total of 33 months.
