BackgroundSialocele is a collection of saliva that has leaked from a damaged salivary gland or duct and is surrounded by granulation tissue. Surgery is the recognized first‐line treatment. Recurrence rate after surgery is 5–14%. Salivary gland tissue is very sensitive to radiation therapy (RT).Hypothesis/ObjectivesRadiation therapy will be useful for the treatment of sialocele. The aims were to characterize response rate and clinical course of dogs with sialocele treated with RT and to determine a starting dose for clinical use.AnimalsEleven dogs with sialocele.MethodsRetrospective study of response and outcome after RT.ResultsAll dogs had cervical sialocele. Seven dogs (63.6%) were treated with 3 weekly fractions of 4 Gray (Gy); (total dose, 12 Gy). Three dogs (27.3%) received 4 fractions of 4 Gy (16 Gy) and 1 dog received 5 fractions of 4 Gy (20 Gy) on a Monday‐Wednesday‐Friday schedule. Six dogs (54%) achieved a complete response (CR), and 5 dogs (45%) achieved a partial response (PR). Three dogs had progression of their sialocele 2, 3, and 9 months after RT; all three had received 12 Gy initially and 2 received 2 additional fractions of 4 Gy (cumulative total dose, 20 Gy) and subsequently achieved remission for >2 years.Conclusions and Clinical ImportanceRadiation therapy is useful for the treatment of recurrent sialocele refractory to surgical management and a minimum total dose of 16 or 20 Gy in 4 Gy fractions appears effective.

Thirty dogs with spontaneous tumors were irradiated with proton therapy using a novel spot scanning technique to evaluate the safety and efficacy of the system, and to study the acute and late radiation reactions. Nasal tumors, soft tissue sarcomas, and miscellaneous tumors of the head were treated with a median total dose of 52.5 Gy given in 3.5 Gy fractions. Acute effects, late effects, tumor response, and outcome were analyzed. No unexpected radiation reactions were seen, however two dogs did develop in-field osteosarcoma, and one dog developed in-field bone necrosis. Complete response to therapy was seen in 40% (12/30), partial response in 47% (14/30), and no response in 13% (4/30). Median survival for all dogs was 385 days (range of 14-4583 days). Dogs with nasal cavity tumors had a median survival of 385 days (range of 131-1851 days) and dogs with soft tissue sarcomas had a median survival time of 612 days (range of 65-4588 days). Treatment outcome was similar to historical controls. This new proton spot scanning technique proved to be safe and reliable.

Zusammenfassung: Gegenstand: Zur Evaluation der Wirkung der Strahlentherapie bei großen hypophysären Tumoren und hypophysär bedingtem Hyperadrenokortizismus bei Hunden wurde eine prospektive Studie durchgeführt. Material und Methode: Sieben Hunde wurden nur strahlentherapeutisch behandelt, während sechs andere nach der Strahlentherapie eine medikamentöse Behandlung erhielten. Der Effekt der Strahlentherapie auf die Tumorgröße und die hormonelle Funktion der Hypophyse wurden mithilfe von CT-Kontrollen und ACTH-Stimulationstests beurteilt. Ergebnisse: Eine Verbesserung der neurologischen Symptome trat bei allen Hunden ein. Die Kortisolproduktion musste jedoch mit Medikamenten unterdrückt werden. Eine deutliche Reduktion der Tumorgröße zeigte sich bei den CT-Kontrollen. Die Patienten tolerierten die Bestrahlung der Hypophysentumoren gut. Wesentliche Nebenwirkungen wurden nicht beobachtet. Schlussfolgerung und klinische Relevanz: Strahlentherapie in Kombination mit systemischer Behandlung des Hyperadrenokortizismus zeigte sich effektiv in der Therapie von hypophysären Tumoren bei Hunden.