Prognostic factors and survival following radiation therapy for canine nasal tumors: A single-institution retrospective study of 166 cases.

Abstract

Prognostic factors in dogs with nasal tumors include several variables. However, factors that can measure prognosis have not yet been identified due to considerable divergence among reports. To describe the computed tomography (CT) imaging, treatment, and outcomes of dogs with nasal tumors, as well as detect negative prognostic factors through the analysis of a substantial number of cases from a single institution. Furthermore, based on CT findings, this study aimed to identify independent prognostic factors for nasal tumors in dogs. A total of 166 client-owned dogs were diagnosed with nasal tumors at Gifu University Veterinary Hospital between 2015 and 2019. Data were retrospectively collected from the electronic medical records. Univariate analysis revealed a significant difference in survival time between adenocarcinoma and squamous cell carcinoma in 166 canine nasal tumors treated with megavoltage (MeV) radiation therapy at a single institution (p = .015). There was a significant difference in survival time between carcinoma and sarcoma (p = .04). Regarding CT imaging findings, significant differences in survival time were observed for frontal sinus invasion (p = .007), cribriform plate destruction (p < .001), and lymph node metastasis (p = .003). Multivariate Cox regression analysis was performed to assess frontal sinus invasion, cribriform plate destruction, histopathologic subtypes, and lymph node metastasis as negative prognostic factors; however, only cribriform plate destruction was a significant negative prognostic factor for survival time (p = .004). Multivariate Cox regression analysis showed that cribriform plate destruction was the main factor in predicting a negative prognosis among 166 canine nasal tumors treated with MeV radiation therapy at a single institution. Therefore, we propose a new 2-tier staging classification for canine nasal tumors with the presence or absence of cribriform plate destruction based on CT examination as the only evaluation factor.