Diagnosis, Prognosis, and Treatment of Canine Hemangiosarcoma: A Review Based on a Consensus Organized by the Brazilian Association of Veterinary Oncology, ABROVET.

Hemangiosarcoma is a mesenchymal neoplasm originating in the endothelial cells of blood vessels; they can be classified as non-visceral and visceral types. Non-visceral hemangiosarcomas can affect the skin, subcutaneous tissues, and muscle tissues; visceral hemangiosarcomas can affect the spleen, liver, heart, lungs, kidneys, oral cavity, bones, bladder, uterus, tongue, and retroperitoneum. Among domestic species, dogs are most affected by cutaneous HSA. Cutaneous HSA represents approximately 14% of all HSA diagnosed in this species and less than 5% of dermal tumors, according to North American studies. However, Brazilian epidemiological data demonstrate a higher prevalence, which may represent 27 to 80% of all canine HSAs and 13.9% of all skin neoplasms diagnosed in this species. Cutaneous HSA most commonly affects middle-aged to elderly dogs (between 8 and 15 years old), with no gender predisposition for either the actinic or non-actinic forms. The higher prevalence of cutaneous HSA in some canine breeds is related to lower protection from solar radiation, as low skin pigmentation and hair coverage lead to greater sun exposure. Actinic changes, such as solar dermatosis, are frequent in these patients, confirming the influence of solar radiation on the development of this neoplasm. There are multiple clinical manifestations of hemangiosarcoma in canines. The diagnostic approach and staging classification of cutaneous HSAs are similar between the different subtypes. The definitive diagnosis is obtained through histopathological analysis of incisional or excisional biopsies. Cytology can be used as a presurgical screening test; however, it has little diagnostic utility in cases of HSA because there is a high risk of blood contamination and sample hemodilution. Surgery is generally the treatment of choice for dogs with localized non-visceral HSA without evidence of metastatic disease. Recently, electrochemotherapy (ECT) has emerged as an alternative therapy for the local ablative treatment of different neoplastic types; the use of radiotherapy for the treatment of dogs with cutaneous HSA is uncommon. There is greater consensus in the literature regarding the indications for adjuvant chemotherapy in subcutaneous and muscular HSA; doxorubicin is the most frequently used antineoplastic agent for subcutaneous and muscular subtypes and can be administered alone or in combination with other drugs. Other therapies include antiangiogenic therapy, photodynamic therapy, the association of chemotherapy with the metronomic dose, targeted therapies, and natural products. The benefits of these therapies are presented and discussed. In general, the prognosis of splenic and cardiac HSA is unfavorable. As a challenging neoplasm, studies of new protocols and treatment modalities are necessary to control this aggressive disease.

Tratamento quimioterápico das neoplasias mamárias em cadelas e gatas / Chemotherapeutic treatment of mammary neoplasms in female dogs and cats

A neoplasia mamária é um tumor freqüentemente observado na rotina da clínica veterinária. A ocorrência desta neoplasia está relacionada principalmente a fatores hormonais. O diagnóstico desta enfermidade é confirmado por biópsia excisional e exame histopatológico. Exame físico e radiografias torácicas devem ser realizados para pesquisa de metástase. Os tumores mamários devem ser avaliados quanto ao seu diâmetro, envolvimento de linfonodos regionais e presença de metástase. O tratamento de eleição é a excisão cirúrgica do tumor. A quimioterapia é um tratamento adjuvante, cuja finalidade é evitar recidivas locais e metástases, prolongando desta forma, a sobrevida do paciente. Para a escolha da droga quimioterápica, deve-se considerar: classificação histopatológica do tumor, classificação de acordo com o sistema TNM (tumor-nódulo-metástase), estado geral do animal e os efeitos colaterais que podem decorrer da aplicação dos fármacos, como mielossupressão e toxicidade gastrointestinal. Os principais quimioterápicos antineoplásicos empregados no tratamento das neoplasias mamárias são a doxorrubicina, a ciclofosfamida e o 5-Fluorouracil.

Mammary gland tumors are often observed in the practice of veterinary clinics. The occurrence of this tumor is specialy 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 lymphnodes 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-node-metastasis), 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.