Long-term adjuvant metronomic chemotherapy in a dog with recurrent maxillofacial osteosarcoma

Abstract

Osteosarcoma (OSA) is the most common malignant bone tumour in dogs; however, OSA of the maxilla is uncommon compared to appendicular OSA. Oral melanoma also commonly occurs in dogs with frequent distant metastasis. The role of adjuvant chemotherapy has been questioned in maxillary OSA and melanoma. A 17-year-old English Cocker Spaniel was referred with a growing mass on the right maxilla and a right lower lip mass. Osteosarcoma was diagnosed after partial maxillectomy, and the right lower lip mass was diagnosed as oral melanoma. Metronomic chemotherapy (MC) was performed, and the number of doses was tapered due to side effects at 5 weeks after initiation of MC. After 130 weeks of MC, chemotherapy was suspended due to kidney disease. After the suspension of chemotherapy, findings suggesting recurrence and metastasis were detected. The dog suddenly died 193 weeks after surgery, which was 8-14 times longer than the expected survival time.To the best of our knowledge, this is the first case report of successful long-term combination therapy, including surgery and MC, in a dog with maxillary OSA and lip melanoma. Our results show that the survival time can be greatly extended if MC is performed with proper management.

Metronomic chemotherapy: bridging theory to clinical application in canine and feline oncology

“…Although they are not discussed in this article given the nature of the study (case report or case series) and/or the number of animals included (less than 5), there are descriptions of the use of MC in the treatment of cutaneous angiomatosis ( 108 ), intradural-extramedullary haemangioblastoma ( 109 ), malignant Leydig cell tumour ( 110 ), malignant mesenchymoma ( 111 ), maxillofacial osteossarcoma ( 112 ), omentum myxosarcoma ( 113 ), prostatic leiomyosarcoma ( 114 ) and tonsillar carcinomas ( 115 ) in dogs and abdominal ( 116 ) and urinary bladder ( 117 ) hemangiosarcomas in cats.…”