VETINDEX

Periódicos Brasileiros em Medicina Veterinária e Zootecnia

Primary perianal malignant melanoma in a dog - combination therapy

Rossi, Ygor AmaralRibeiro, LeticiaMedeiros, Regina MendesSpugnini, EnricoAlves, Carlos Eduardo FonsecaDos Anjos, Denner Santos

Background: Melanocytic neoplasm can arise from melanocytes in any location of the body. Malignant melanoma (MM)has a poor prognosis in dogs and presence of lymphvascular invasion, distant metastasis, or mitotic activity present prognostic value. Primary melanoma affecting the gastrointestinal tract has been rarely reported in veterinary literature, thusthe prognosis affecting gastrointestinal tract is unknown. Electrochemotherapy (ECT) is an effective local treatment whichcombines chemotherapeutic drugs mainly bleomycin or cisplatin followed by the delivery of permeabilizing electricalpulses However, other hydrophilic drugs seem to present an increase cytotoxic effect such as carboplatin.Case: A 9-year-old mixed-breed neutered dog was referred to a private clinic with a mass in the perianal region diagnosedas perianal melanoma. No metastasis was observed on abdominal ultrasound nor chest x-ray (3 views). Clinical signs notedwere tenesmus, hemorrhagic discharge, weight loss and hyporexia. Considering the tumor volume (16.0 x 10.0 cm), a neoadjuvant ECT session was proposed. The authors opted for carboplatin (300 mg/m2, intravenously), administered over 20min and cisplatin intratumorally (1 mg/cm3, equivalent to 1 mL/1cm3 total volume 20 mL) administered in the upper partsof the mass that could be reached while avoiding drug leakage. After administration, sequences of eight biphasic pulses,(100 microseconds), with a voltage ranging from 650-1,000V/cm (pulse generator Onkodisruptor®) using a hexagonal/single pair and plate electrode were delivered. At day 30th, a partial response was observed accordingly to RECIST system,with tumor size of 5.0 x 5.0 cm (65.4 cm3). A second ECT session was performed with the same previous protocol, butwith a decreased dosage of carboplatin (240 mg/m2 consistent with 20% reduction) due to adverse effects in the first session, resulting in stable disease at day 60th (30 days after second ECT). Then...(AU)

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