Clinical features, diagnosis, and survival analysis of dogs with glioma.

Background: Gliomas in dogs remain poorly understood. Objectives: To characterize the clinicopathologic findings, diagnostic imaging features and survival of a large sample of dogs with glioma using the Comparative Brain Tumor Consortium diagnostic classification. Animals: Ninety‐one dogs with histopathological diagnosis of glioma. Methods: Multicentric retrospective case series. Signalment, clinicopathologic findings, diagnostic imaging characteristics, treatment, and outcome were used. Tumors were reclassified according to the new canine glioma diagnostic scheme. Results: No associations were found between clinicopathologic findings or survival and tumor type or grade. However, definitive treatments provided significantly (P =.03) improved median survival time (84 days; 95% confidence interval [CI], 45‐190) compared to palliative treatment (26 days; 95% CI, 11‐54). On magnetic resonance imaging (MRI), oligodendrogliomas were associated with smooth margins and T1‐weighted hypointensity compared to astrocytomas (odds ratio [OR], 42.5; 95% CI, 2.42‐744.97; P =.04; OR, 45.5; 95% CI, 5.78‐333.33; P <.001, respectively) and undefined gliomas (OR, 84; 95% CI, 3.43‐999.99; P =.02; OR, 32.3; 95% CI, 2.51‐500.00; P =.008, respectively) and were more commonly in contact with the ventricles than astrocytomas (OR, 7.47; 95% CI, 1.03‐53.95; P =.049). Tumor spread to neighboring brain structures was associated with high‐grade glioma (OR, 6.02; 95% CI, 1.06‐34.48; P =.04). Conclusions and Clinical Importance: Dogs with gliomas have poor outcomes, but risk factors identified in survival analysis inform prognosis and the newly identified MRI characteristics could refine diagnosis of tumor type and grade. [ABSTRACT FROM AUTHOR]