A 3-year-old neutered male mixed-breed cat was presented with a mass on the rostral mandible, which was histopathologically diagnosed as a sarcoma. Complete resection with bilateral rostral mandibulectomy was performed, and the postoperative histopathological analysis confirmed the diagnosis of an osteosarcoma. Adjuvant chemotherapy with carboplatin was administered six times. The prognosis was satisfactory, with no recurrence or metastasis after 3 years postoperatively.

In human medicine, anticancer drug contamination in hospitals is a major issue. While anticancer drugs are also used to treat dogs and cats, its associated contamination in veterinary practice remains unclear. This study investigated environmental contamination with anticancer drugs in two veterinary hospitals （a university hospital and a private hospital）. Cyclophosphamide residues were assessed using multiple wipe tests. In the university hospital, the wipe tests were repeated one year and six months after the previous survey to evaluate the effectiveness of implementing occupational exposure countermeasures and rules for anticancer drug handling. Such measures included wearing personal protective equipment, using a closed system drug transfer device （CSTD）, and regular cleaning of surfaces with anticancer drug decomposition solution. In the university hospital, cyclophosphamide was detected primarily in the isolator, but also in multiple locations outside the isolator. In the private hospital, regular cleaning with an anticancer drug-decomposing solution reduced contamination. Following the introduction of occupational exposure countermeasures, the wipe test revealed cyclophosphamide residues only within the isolator, and in a significantly lower amount than the previous test. Our findings show that implementing preventive measures, such as the use of CSTDs and hospital rules for anticancer drug handlings, reduce environmental contamination in veterinary hospitals.