Adverse events and outcomes in dogs with appendicular osteosarcoma treated with limb amputation and a single subcutaneous infusion of carboplatin.

Objective: To evaluate adverse events and outcomes in dogs with appendicular osteosarcoma treated with limb amputation followed by a single SC infusion of carboplatin.

Animals: 45 client-owned dogs with appendicular osteosarcoma treated with limb amputation and SC infusion of carboplatin between January 1, 2006, and January 15, 2017.

Procedures: Medical records were reviewed, and data collected included signalment, tumor location, treatment, results of clinicopathologic analyses and diagnostic imaging, adverse effects of chemotherapy, metastasis-free interval, survival time, and communications with owners and referring veterinarians. Findings were evaluated with the Kaplan-Meier survival analysis and Mantel-Haenszel log-rank test.

Results: 45 dogs were identified that met the inclusion criteria (12 of the 45 dogs had been reported in a previous case series). No dogs had pulmonary metastases detectable by CT or radiography before treatment. All dogs completed the protocol as planned. Median survival time (MST) was 196 days; metastasis-free interval was 197 days. Three of the 45 (7%) dogs required hospitalization for gastrointestinal signs related to chemotherapy. There were no chemotherapy-related deaths.

Conclusions And Clinical Relevance: Results indicated that although treatment with SC infusion of carboplatin was well tolerated, the MST for dogs in the present study was similar to reported MSTs in dogs with appendicular osteosarcoma treated with limb amputation alone and was in the lower range of historically reported survival times for dogs receiving IV adjunctive chemotherapy. Therefore, we could not recommend this protocol of SC infusion of carboplatin but recommended that protocols with IV administration of carboplatin be used instead.