Outcome predictors for dogs with bone cancer treated by carboplatin

Abstract

OBJECTIVE: To determine outcomes and prognostic factors for those outcomes in dogs with appendicular osteosarcoma treated with curative-intent surgery and adjuvant carboplatin. DESIGN: Retrospective case series. ANIMALS: 65 client-owned dogs with appendicular osteosarcoma and no evidence of gross metastatic disease at the time of diagnosis. PROCEDURES: Medical records of dogs that underwent limb amputation or distal ulnectomy and adjuvant carboplatin treatment for appendicular osteosarcoma were reviewed. Adverse effects of chemotherapy and findings regarding preoperative biopsy specimens and postoperative diagnostic imaging were recorded. Signalment, clinical history, and chemotherapy variables were evaluated for associations with outcome. Histologic grade and other variables were evaluated for association with outcome for 38 tumors that were retrospectively graded. RESULTS: The median disease-free interval was 137 days (95% confidence interval [CI], 112 to 177 days). Median survival time was 277 days (95% CI, 203 to 355 days). The 1-, 2-, and 3-year survival rates were 36%, 22%, and 19%, respectively. None of the chemotherapy variables were associated with outcome. Preoperative proteinuria was the only clinical variable associated with poor outcome. Histologic features of tumors associated with a poor outcome were intravascular invasion, mitotic index > 5 in 3 microscopic hpfs, and grade III classification. CONCLUSIONS AND CLINICAL RELEVANCE: Carboplatin administration was well tolerated and resulted in a disease-free interval and median survival time similar to those of other published protocols.