Palliative radiation therapy for solid tumors in dogs: 103 cases (2007-2011).

Objective: To evaluate the clinical response, adverse effects, and outcomes associated with palliative radiation therapy (PRT) in dogs with various solid tumor types at various body locations.

Design: Retrospective case series.

Animals: 103 dogs with solid tumors.

Procedures: Medical records for dogs with solid tumors treated with PRT between July 2007 and January 2011 at a veterinary teaching hospital were reviewed. Data collected included signalment, tumor type and location, initial staging results, PRT protocol, other tumor-specific treatments, patient and tumor response, outcome, and acute and chronic adverse effects. Median progression-free survival time, median survival time (MST), and other descriptive statistics were calculated.

Results: Types of tumors treated included carcinoma, sarcoma, melanoma, primary bone tumor, mast cell tumor, and ameloblastoma. For all dogs, the overall tumor and clinical response rates to PRT were 75% and 77%, respectively, and the MST was 134 days, but those responses varied substantially among tumor types. Dogs that developed a positive clinical response or maintained stable disease after PRT had a significantly longer MST than did dogs with progressive disease. Tumor location was not significantly associated with median progression-free survival time or MST. Most dogs tolerated the PRT well. Acute and chronic adverse effects were observed in 57 and 8 dogs, respectively, but were generally self-limiting.

Conclusions And Clinical Relevance: Results indicated that dogs with various types of solid tumors that received PRT had objective beneficial responses and an improvement in quality of life that was positively associated with survival time.