IRRADIATION OF NONLYMPHOPROLIFERATIVE NEOPLASMS OF THE NASAL CAVITY AND PARANASAL SINUSES IN 16 CATS

Sixteen cats with malignant tumors (10 carcinomas, 6 sarcomas) of the nasal cavity and paranasal sinuses were treated with curative intent b y radiotherapy. Clinical staging was based on radiographic findings, u sing the tumor, node, metastasis classification system of the World He alth Organization. Irradiation was done with a telecobalt-60 unit (13 cats) and an orthovoltage unit (3 cats). Fourteen cats weve treated wi th irradiation alone, and 2 cats had incomplete surgical resections pr ior to radiotherapy. Treatment dose was 48 Gy (minimum tumor dose), ad ministered by use of 4 cy per fraction on a Monday/Wednesday/Friday ba sis over 4 weeks. Survival times after treatment ranged from 1 to 36 m onths. The 1- and 2-year overall survival rates were 44.3 and 16.6%, r espectively. Histologic type and clinical stage did not have prognosti c value. Most acute radiation reactions were mild and self-limiting. C hronic ocular complications were seen in 3 cats. These treatment respo nses compared favorably with those previously described in dogs and ca ts with intranasal neoplasms treated with teletherapy and provided a p erspective for comparison of new treatment methods.