Intracranial neoplasia occurs more frequently in dogs than in humans (14.5 per year per 100,000 canine populations at risk compared with 4-5 per 100,000 humans) (Frenier 1990, Kornegay 1986). Canine glioma reportedly occurs most commonly in brachycephalic breeds such as Boxers and Boston terriers (Snyder 2006). No sex predilection has been reported and brain tumors are recognized with greater incidence in animals over six years of age. Gliomas can arise in most any location in the brain, but are morecommonly supratentorial. We and others have found many similarities between human and canine GBM such as: overexpression of the epidermal growth factor receptor and mutation of the p53 tumor suppressor gene, extensive invasion into normal brain, peritumoral edema and necrosis, hemorrhage, compression, herniation, and obstructive hydrocephalus. Similar to that in humans, the prognosis for dogs with brain tumors in general is poor regardless of therapeutic intervention. However, much less is known aboutcanine glioma treatment outcomes because only a small number of studies with few dogs have been reported. The median survival time for dogs with glioma that did not receive any type of treatment ranges between 6 and 13 days (Foster 1988, Heidner 1991), and between 60 and 80 days in dogs that receive palliative therapy only (Turrel 1986, LaRue 2001). Radiation therapy may have increased survival time in one dog with glioma (176 days) as compared to corticosteroid therapy in three dogs with glioma (18, 40and 64 days) (Turrel 1986). We calculated the survival data for 9 dogs recently diagnosed with glioma based on MRI characteristics of an intra-axial mass at our institution. The median survival time of these dogs that did not receive any therapy other than corticosteroids and anticonvulsants was 29 days, range 1-128 days.
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