Frameless stereotactic radiotherapy alone and combined with temozolomide for presumed canine gliomas.

We evaluated stereotactic volume modulated arc radiotherapy (VMAT) for canine gliomas, alone (radiotherapy [RT]) and in combination with temozolomide (RT + TMZ), compared with palliation. Overall and disease-specific survival times were estimated. Thirty dogs were palliated, 22 dogs were treated with RT and 20 with RT + TMZ. Complete and partial responses were observed in 63.2% and 90.9% of patients in the RT and RT + TMZ arms, respectively, that were alive at 1 year. Median survival in the palliation arm was 94 days (95% conformity index [CI] 87÷101). Median survivals of the RT arm (383 days, 95% CI 276÷490) and RT+TMZ arm (420 days, 95% CI 280÷560) were not significantly different (P = .61). Positive correlation with survival was found both for the ratio between target and brain (relative) volume of the tumour of <5% (P = .013) and for a clinical presentation with normal mentation (P = .032). VMAT is feasible and effective for canine brain gliomas. Combining this therapy with TMZ did not elicit any additional improvement in survival time.

Volumetric-modulated arc stereotactic radiotherapy for canine adrenocortical tumours with vascular invasion.

OBJECTIVES: To evaluate the feasibility and efficacy of hypofractionated stereotactic volumetric-modulated arc radiotherapy in treating canine adrenal tumours with vascular invasion. METHODS: A single-arm clinical study was performed. The dogs underwent total body computed tomography, brain and abdomen magnetic resonance imaging and endocrine assay. Adrenal masses were classified as cortisol-secreting adrenal tumour or non-secreting adrenal tumour. Radiotherapy treatments were delivered by hypofractionated stereotactic volumetric-modulated arc radiotherapy via a linear accelerator. The overall survival was estimated by the Kaplan-Meier method. The overall response and radio-toxicity effects were determined. RESULTS: Nine dogs were enrolled. Three dogs were affected by cortisol-secreting adrenal tumours and the remaining dogs had non-secreting adrenal tumours. The prescribed doses ranged from 30 to 45 Gy in three or five consecutive daily fractions. The median overall survival time was 1030 days, and the overall mean reduction of the diameter and volume were ~32 and 30% respectively. The endocrine profile normalised in two dogs with cortisol-secreting adrenal tumours. Radio-toxicities were mild and self-limiting. Seven deaths were recorded during the follow-up period and two dogs were censored. CLINICAL SIGNIFICANCE: Hypofractionated stereotactic volumetric-modulated arc radiotherapy should be considered as a feasible and effective therapeutic option for adrenal tumours with vascular invasion.