Abstract
Treatment of epithelial sinonasal tumors in cats is not commonly reported. Palliative radiation protocols have been described more often than definitive-intent protocols. In this multi-institutional retrospective study, we included 27 cats treated with single-modality radiotherapy. Cats were irradiated using 10 daily fractions of 4.2Gy. Three cats (11.1%) experienced a complete clinical response and 17 (63%) had a partial clinical response. Stable clinical disease was noted in three cats (11.1%). Four cats (14.8%) showed progression within 3 months following treatment. The median time to progression for all cases was 269 days (95% CI: 225;314). The proportion of cats free of progression at 1 and 2 years was 24% (95%CI: 22%;26%) and 5% (95%CI: 5%;6%), respectively. None of the prognostic factors evaluated were predictive of outcome (anemia, tumor volume at the time of staging, modified Adams stage, intracranial involvement, facial deformity, epistaxis, inappetence or weight loss). Median overall survival (OS) for all deaths was 452 days (95%CI: 334;571). The proportion of cats alive at 1 and 2 years was 57% (95%CI: 37%;77%) and 27% (95%CI: 25%;29%), respectively. Surprisingly, cats with epistaxis had a longer median OS of 828 days (95%CI: 356;1301) compared to 296 days (95%CI: 85;508) in cats without epistaxis, (p=0.04, Breslow). Radiation therapy used as a single modality for the treatment of feline sinonasal carcinoma improved clinical signs and was well tolerated.