Diagnosis, Prognosis, and Treatment of Canine Hemangiosarcoma: A Review Based on a Consensus Organized by the Brazilian Association of Veterinary Oncology, ABROVET
Authors: De Nardi Andrigo Barboza , de Oliveira Massoco Salles Gomes Cristina , Fonseca-Alves Carlos Eduardo , de Paiva Felipe Noleto , Linhares Laís Calazans Menescal , Carra Gabriel João Unger , dos Santos Horta Rodrigo , Ruiz Sueiro Felipe Augusto , Jark Paulo Cesar , Nishiya Adriana Tomoko , de Carvalho Vasconcellos Carmen Helena , Ubukata Rodrigo , Batschinski Karen , Sobral Renata Afonso , Fernandes Simone Crestoni , Biondi Luiz Roberto , De Francisco Strefezzi Ricardo , Matera Julia Maria , Rangel Marcelo Monte Mor , dos Anjos Denner Santos , Brunner Carlos Henrique Maciel , Laufer-Amorim Renee , Cadrobbi Karine Germano , Cirillo Juliana Vieira , Martins Mauro Caldas , de Paula Reis Filho Nazilton , Silva Lessa Diego Fernando , Portela Roberta , Scarpa Carneiro Carolina , Ricci Lucas Sílvia Regina , Fukumasu Heidge , Feliciano Marcus Antônio Rossi , Gomes Quitzan Juliany , Dagli Maria Lucia Zaidan 
Published: March 2023

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.