Lomustine for treatment of canine transmissible venereal tumor/Eficacia da lomustina no tratamento do tumor venereo transmissivel canino

Canine transmissible venereal tumor (TVTC) is a highly casuistic transmissible neoplasm in Brazil. Chemotherapy with vincristine sulfate is considered the treatment of choice, but the need for weekly applications and hematological monitoring, in addition to costs, are obstacles to owners' adhesion to the treatment. Lomustine is an alkylating class antineoplastic agent, and because it is administered orally, it is a more practical and less costly treatment option for the owners of animals with neoplasms sensitive to the drug. This study evaluated the therapeutic efficacy of lomustine in dogs affected by TVTC. Twelve dogs with cytopathological diagnosis of natural genital TVTC were selected. The dogs were submitted to the experimental protocol with lomustine administration at doses of 70 to 85 mg/[m.sup.2] orally every 21 days, totaling a maximum of two administration cycles. The animals were reevaluated every 7 days until a maximum of+49 days after the first dose of lomustine, to monitor the regression of neoplastic lesions through measurements. Among the 12 dogs submitted to the lomustine protocol, 8/12 achieved complete remission of the neoplasm and were considered cured (66.6%), 1/12 had partial response to treatment (8.33%) and 3/12 had stable disease (25%). Important adverse effects such as severe neutrophilic leukopenia were detected in 3/12 dogs (25%). The clinical study indicated that lomustine may be a treatment option for TVTC. Key words: neoplasm, chemotherapy, alkylants, lomustine, venereal tumour, dogs. O tumor venereo transmissivel canino (TVTC) e uma neoplasia transmissivel de elevada casuistica no Brasil. A quimioterapia com sulfato de vincristina e considerada o tratamento de escolha, mas a necessidade de aplicacoes semanais e acompanhamento hematologico, alem dos custos, sao obstaculos a adesao dos proprietaries ao tratamento. A lomustina e um antineoplasico da classe dos agentes alquilantes e, por ser administrado por via oral., representa um opcao de tratamento mais pratica e menos onerosa para os proprietaries de animais com neoplasias. O objetivo deste estudo foi avaliar a eficacia terapeutica da lomustina em caes acometidos por TVTC. Foram selecionados 12 caes com diagnostico citopatologico de TVTC genital de ocorrencia natural. Os caes foram submetidos ao protocolo experimental com administracao de lomustina nas doses de 70 a 85 mg/[m.sup.2] por via oral a cada 21 dias, totalizando no maximo dois ciclos de administracao. Os animais f