Long-term management of mandibular osteosarcoma in a dog using toceranib after hemimandibulectomy

A 6-year-old castrated male golden retriever dog weighing 32.6 kg was presented for chemotherapy after hemimandibulectomy due to mandibular osteosarcoma. Considering the incomplete surgical excision and metastatic potential, adjuvant chemotherapy was considered. Oral toceranib (2.76 mg/kg, PO, q48h) was initiated after a nodule was palpated at the surgical site 4 wk following hemimandibulectomy. During treatment, the drug dose was decreased due to mildly increased creatinine levels. However, after 1 mo, the dose was increased because creatinine had decreased to previous values. The animal experienced vomiting and diarrhea 7 mo after toceranib initiation; therefore, the drug was stopped for 1 wk. After that point, except for mild neutropenia, no other clinicopathological abnormalities, clinical signs, recurrence, or metastasis occurred. The toceranib therapy provided a durable disease-free interval in this case. Therefore, oral toceranib therapy can be an option for adjuvant chemotherapy for canine mandibular osteosarcoma. Key clinical message: In this case, which was characterized by the overexpression of various receptor tyrosine kinase genes, oral toceranib administration provided a durable disease-free interval in a dog. Further studies are warranted to evaluate the general application of toceranib for the management of canine mandibular osteosarcoma.