Osteosarcoma in dogs Analysis of patients between 1960 and 2012 in the Netherlands

Abstract

Osteosarcoma is the most common primary bone tumor in dogs and forms metastases to mostly the lungs in early course of the disease. Diagnosis is made by biopsy and histologic evaluation. There are a lot of different treatment protocols with different therapy modalities (e.g. surgery, chemotherapy, radiotherapy, medical management). There are several negative prognostic factors for osteosarcoma. This is a retrospective case study to determine prognostic factors for the survival time and metastasis free interval in dogs with osteosarcoma. 298 dogs presented at different clinics in the Netherlands with histologically confirmed osteosarcoma are used. The individual data of the patients are inserted into a database. The survival time and metastasis free interval of different groups is compared with the Kaplan-Meier curve and logrank test. The significant differences with the Kaplan-Meier analysis are investigated with the cox proportional hazard regression model. The metastasis free interval is significant negative influenced in the univariate analysis by breed, axial localization, localization in the proximal humerus, leukocytosis and high neutrophil counts, no treatment and marginal resection. Localization in the distal tibia has a significant positive influence on the metastasis free interval in the univariate analysis. In the multivariate analysis only localization in the humerus, neutrophil count and preoperative presence of metastasis significantly influence the metastasis free interval. The survival time is significant negative influenced with the Kaplan-Meier method by localization in the axial skeleton, in the proximal humerus and localization in the middle, high leucocytes and neutrophils, the presence of metastasis and incomplete resection of the osteosarcoma. Localization in the distal radius, perform surgery, perform chemotherapy and the combination of amputation and chemotherapy have a significant positive influence on the survival time by the Kaplan-Meier method. In the cox regression analysis only neutrophil and thrombocyte count significantly influenced the survival time.