Resumo (EN)
Mammary gland tumors are often observed in the practice of veterinary clinics. The occurrence of this tumor is speccialy related to hormonal factors. The diagnosis is confirmed by excisional biopsy and histopathologic evaluation. Physical examination and chest radiographs should be taken to evaluate possible metastasis. Mammary gland tumors must be evaluated for tumor size, regional lymph nodes involvement and presence of metastasis. The treatment of choice is surgical excision of the tumor. Chemotherapy is an adjuvant treatment, whose goal is to avoid local recurrence and metastasis, extending this way, the patient’s survival. To choice the chemotherapy drug, it must consider: tumor histopathologic classification, classification according to the TNM system (tumor-nodemetastasis), animal’s general health and the side effects that can occur from the use of the drugs, like myelossupression and gastrointestinal toxicity. The prime chemotherapy drugs used in the treatment of mammary gland tumors are doxorubicin, cyclophosphamide and 5-fluorouracil.