Prognostic factors for surgical treatment of soft-tissue sarcomas in dogs: 75 cases (1986-1996)

OBJECTIVE: To determine results of surgery for treatment of soft-tissue sarcomas in dogs and to identify prognostic variables that can be used to predict outcome. DESIGN: Retrospective case series. ANIMALS: Dogs with soft-tissue sarcomas that had surgical treatment only. PROCEDURE: Records were examined for clinically relevant data. Histologic samples were reviewed. Follow-up information was obtained by physical examination or telephone conversations with referring veterinarians or owners. RESULTS: 75 dogs with soft-tissue sarcomas of the trunk and extremities were identified. Median age was 10.6 years. Malignant peripheral nerve sheath tumors were of a significantly lower grade than other tumors. Tumors recurred locally in 11 of 75 (15%) dogs. Evaluation for lack of tumor cells at surgical margins was prognostic for local recurrence. Metastatic disease developed in 13 of 75 (17%) dogs. Tumor mitotic rate was prognostic for development of metastasis. Twenty-five of 75 (33%) dogs died of tumor-related causes. Percentage of tumor necrosis and tumor mitotic rate were prognostic for survival time. Median survival time was 1,416 days. CLINICAL IMPLICATIONS: On the basis of a low local recurrence rate and high median survival time, wide excision of tumor margins or radical surgery appeared to be an effective means for managing soft-tissue sarcomas of the trunk and extremities. Analysis of histologic characteristics for prognosis supported use of preoperative biopsy. Surgical margins should be evaluated, and early use of aggressive surgery is indicated in the management of soft-tissue sarcomas in dogs.