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

Gliomas in dogs remain poorly understood. 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. Ninety-one dogs with histopathological diagnosis of glioma. 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. 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). 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.