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.

Diagnosis, Prognosis and Treatment of Canine Cutaneous and Subcutaneous Mast Cell Tumors.

Mast cell tumors (MCTs) are hematopoietic neoplasms composed of mast cells. It is highly common in dogs and is extremely important in the veterinary oncology field. It represents the third most common tumor subtype, and is the most common malignant skin tumor in dogs, corresponding to 11% of skin cancer cases. The objective of this critical review was to present the report of the 2nd Consensus meeting on the Diagnosis, Prognosis, and Treatment of Canine Cutaneous and Subcutaneous Mast Cell Tumors, which was organized by the Brazilian Association of Veterinary Oncology (ABROVET) in August 2021. The most recent information on cutaneous and subcutaneous mast cell tumors in dogs is presented and discussed.

Canine visceral hemangiosarcoma treated with surgery alone or surgery and doxorubicin: 37 cases (2005-2014).

The purpose of this retrospective study was to determine survival times and prognostic factors of dogs with visceral hemangiosarcoma (HSA) treated with surgery alone or surgery and doxorubicin. Medical records from 2 hospitals from 2005 to 2014 were searched for dogs with histopathologically confirmed visceral HSA. Data relevant to patient demographics, tumor characteristics, and outcomes were abstracted. The most common primary organ affected was the spleen; however, primary tumor location had no influence on prognosis. Twenty-three dogs were treated with surgery alone, while 14 dogs were treated with surgery and doxorubicin. There was a significant difference in survival times between dogs treated with surgery alone and with surgery followed by doxorubicin (66 days versus 274 days). Dogs with stage I tumors (196 days) had a longer median survival time (MST) than dogs with stage II (117 days) and stage III (23 days) disease. The overall MST was 179 days with a 1-year survival rate of 29.2%.

Hémangiosarcome viscéral canin traité par la chirurgie seule et la doxorubicine : 37 cas (2005­2014). Le but de cette étude rétrospective consistait à déterminer les temps de survie et les facteurs de pronostic des chiens atteints d'un hémangiosarcome (HSE) viscéral traités à l'aide de la chirurgie seule ou de la chirurgie et de la doxorubicine. Les dossiers médicaux de deux cliniques de 2005 à 2014 ont été fouillés pour trouver des chiens avec un HSE viscéral confirmé par histopathologie. Les données pertinentes pour les données démographiques du patient, les caractéristiques de la tumeur et les résultats ont été extraits des dossiers. L'organe primaire le plus couramment affecté était la rate. Cependant, l'emplacement primaire de la tumeur n'avait aucune influence sur le pronostic. Vingt-trois chiens ont été traités par la chirurgie seule, tandis que 14 chiens ont été traités par la chirurgie et la doxorubicine. Il y avait une différence importante dans les temps de survie entre les chiens traités par la chirurgie seule et la chirurgie suivie de la doxorubicine (66 jours contre 274 jours). Les chiens ayant des tumeurs de stade I (196 jours) avaient un temps de survie médian (TSM) plus long que les chiens atteints d'une maladie de stade II (117 jours) et de stade III (23 jours). Le TSM général était de 179 jours avec un taux de survie après 1 an de 29,2 %.(Traduit par Isabelle Vallières).

Combination of Bleomycin and Cytosine Arabinoside Chemotherapy for Relapsed Canine Lymphoma.

A retrospective study was performed to evaluate response rate, time to progression, and toxicity of a bleomycin and cytosine arabinoside (Bleo/Cytarabine) combination protocol for dogs with relapsed lymphoma (LSA). Dogs diagnosed with LSA and previously treated with chemotherapy were included in the study. A total of 20 dogs met the inclusion criteria, and 19 were evaluable for response. Bleomycin was administered subcutaneously on days 1 and 8 and cytosine arabinoside was administered subcutaneously on days 1-5 of a 21-day cycle. The median number of chemotherapy drugs given prior to the administration of Bleo/Cytarabine was 8.5. A total of 23 cycles of Bleo/Cytarabine were administered. The overall response rate was 36.8% (7 of 19 dogs had a partial response). The median time to progression was 15 days. Three dogs developed grade 3 thrombocytopenia and one dog had a grade 4 neutropenia. Bleo/Cytarabine had minor activity when used as a rescue therapy for pretreated LSA patients.

Comparative Aspects of Canine Melanoma.

Melanomas are malignant neoplasms originating from melanocytes. They occur in most animal species, but the dog is considered the best animal model for the disease. Melanomas in dogs are most frequently found in the buccal cavity, but the skin, eyes, and digits are other common locations for these neoplasms. The aim of this review is to report etiological, epidemiological, pathological, and molecular aspects of melanomas in dogs. Furthermore, the particular biological behaviors of these tumors in the different body locations are shown. Insights into the therapeutic approaches are described. Surgery, chemotherapy, radiotherapy, immunotherapy, and the outcomes after these treatments are presented. New therapeutic perspectives are also depicted. All efforts are geared toward better characterization and control of malignant melanomas in dogs, for the benefit of these companion animals, and also in an attempt to benefit the treatment of human melanomas.