Comparison of two different vinblastine dosages for treatment of cutaneous mast cell tumor in dogs

Background: Mast cell tumors (MCT) are among the most common malignant cutaneous neoplasm in dogs with variable biologic behavior and remain a therapeutic challenge in high-grade cases. Surgery remains the primary treatment for canine MCT; however, chemotherapy and radiation therapy are commonly used to treat aggressive cases. The combination of vinblastine (VBL) at a dose of 2 mg/m² and prednisone is the classically described protocol for MCT treatment. Studies have shown the safety of higher VBL doses for dogs with MCT, but there is a lack of information regarding dose intensity and outcome as a goal after chemotherapy. This study aimed to evaluate the impact of a higher dose of VBL on MCT treatment outcome. Materials, Methods & Results: This was an observational and comparative study conducted in two different Veterinary Teaching Hospitals. Client-owned dogs with histopathological diagnosis of grade II or III MCT were selected and underwent at least four chemotherapy sessions with VBL and prednisone. The experimental group (EG) consisted of 18 dogs that received a dose of 3 mg/m² VBL treated in one institution. The control group (CG) included 31 dogs that received a dose of 2 mg/m² VBL treated at the other institution. All dogs treated in both groups had a clinical and complete blood count (CBC) evaluation performed previous the start of chemotherapy (T0) and before each weekly treatment (T1, T2, T3, and T4). After treatment, dogs in both groups were followed-up for the recurrence rate and overall survival time after diagnosis. There was no significant difference in clinical variables between EG and CG. During treatment, dogs of EG showed a significant reduction in erythrocyte, hemoglobin, and hematocrit values between T0 and T1, T2, T3, and T4 (P < 0.001). Comparatively, the CG showed significant reduction in hemoglobin (P = 0.02) and total leucocytes (P = 0.001) values in the same period. Despite these findings, these hematological...

Outcome of adjuvant chemotherapy with lomustine, vinblastine and chlorambucil on management of canine mast cell tumour of high to intermediate risk / Resultado da quimioterapia adjuvante com lomustina, vimblastina e clorambucil no manejo do mastocitoma canino de risco alto a intermediário

In spite of the many available protocols, the use of chemotherapy for the management of canine mast cell tumours (MCT) remains empirical, and there is lack of criteria for the choice of protocol and definition of patients who may benefit from treatment. The objective of this study was to evaluate the outcome of dogs with MCT after adjuvant chemotherapy according to the risk of recurrence or metastasis proposed on the literature. This prospective study included 89 followed up dogs with prognosis assesment including clinical, histological, immunohistochemical and genetic features of canine MCT. Patients were grouped according to risk of recurrence and metastasis and recommended treatment with lomustine followed by chlorambucil if considered at high-risk, or vinblastine followed by chlorambucil if a patient was at intermediate risk. Outcome was defined by disease-free interval (DFI) and overall survival (OS) estimated by Kaplan-Meier curve. Adjuvant lomustine was useful for control of canine MCT of high-risk of recurrence or metastasis, but only when sequentially associated to chlorambucil with a DFI of 686 days and not reached OS. There was no difference in outcome in the intermediate-risk group despite choosen treatment. Patients at intermediate-to-low risk may not require adjuvant treatments, even in the absence of free surgical margins.(AU)

Apesar dos inúmeros protocolos disponíveis, o uso da quimioterapia permanece empírico para o mastocitoma canino e faltam critérios para escolha do protocolo e da definição dos pacientes que poderiam se beneficiar do tratamento. O objetivo deste estudo foi avaliar o resultado de cães com mastocitoma após a quimioterapia adjuvante, de acordo com o risco de recorrência ou metástase proposto na literatura. Este estudo prospectivo incluiu 89 cães com acompanhamento clínico e avaliação prognóstica, incluindo características clínicas, histológicas, imuno-histoquímicas e genéticas dos mastocitomas. Os pacientes foram agrupados segundo o risco de recorrência ou metástase, sendo recomendado tratamento com lomustina seguida de clorambucila, se considerados sob alto risco, ou vimblastina seguida de clorambucila, se estivessem sob risco intermediário. O resultado final foi definido pelo intervalo livre de doença (ILD) e pela sobrevida global (SG), estimados pela curva de Kaplan-Meier. Na adjuvância, a lomustina foi útil no controle do mastocitoma canino de alto risco, mas apenas quando associada ao clorambucila, com um ILD de 686 dias, sem atingir a mediana para SG. Não houve diferença no grupo de risco intermediário, independentemente do tratamento escolhido. Pacientes de risco intermediário podem não necessitar de tratamentos adjuvantes, mesmo na ausência de margens cirúrgicas livres.(AU)

Outcome of adjuvant chemotherapy with lomustine, vinblastine and chlorambucil on management of canine mast cell tumour of high to intermediate risk / Resultado da quimioterapia adjuvante com lomustina, vimblastina e clorambucil no manejo do mastocitoma canino de risco alto a intermediário

In spite of the many available protocols, the use of chemotherapy for the management of canine mast cell tumours (MCT) remains empirical, and there is lack of criteria for the choice of protocol and definition of patients who may benefit from treatment. The objective of this study was to evaluate the outcome of dogs with MCT after adjuvant chemotherapy according to the risk of recurrence or metastasis proposed on the literature. This prospective study included 89 followed up dogs with prognosis assesment including clinical, histological, immunohistochemical and genetic features of canine MCT. Patients were grouped according to risk of recurrence and metastasis and recommended treatment with lomustine followed by chlorambucil if considered at high-risk, or vinblastine followed by chlorambucil if a patient was at intermediate risk. Outcome was defined by disease-free interval (DFI) and overall survival (OS) estimated by Kaplan-Meier curve. Adjuvant lomustine was useful for control of canine MCT of high-risk of recurrence or metastasis, but only when sequentially associated to chlorambucil with a DFI of 686 days and not reached OS. There was no difference in outcome in the intermediate-risk group despite choosen treatment. Patients at intermediate-to-low risk may not require adjuvant treatments, even in the absence of free surgical margins.(AU)

Apesar dos inúmeros protocolos disponíveis, o uso da quimioterapia permanece empírico para o mastocitoma canino e faltam critérios para escolha do protocolo e da definição dos pacientes que poderiam se beneficiar do tratamento. O objetivo deste estudo foi avaliar o resultado de cães com mastocitoma após a quimioterapia adjuvante, de acordo com o risco de recorrência ou metástase proposto na literatura. Este estudo prospectivo incluiu 89 cães com acompanhamento clínico e avaliação prognóstica, incluindo características clínicas, histológicas, imuno-histoquímicas e genéticas dos mastocitomas. Os pacientes foram agrupados segundo o risco de recorrência ou metástase, sendo recomendado tratamento com lomustina seguida de clorambucila, se considerados sob alto risco, ou vimblastina seguida de clorambucila, se estivessem sob risco intermediário. O resultado final foi definido pelo intervalo livre de doença (ILD) e pela sobrevida global (SG), estimados pela curva de Kaplan-Meier. Na adjuvância, a lomustina foi útil no controle do mastocitoma canino de alto risco, mas apenas quando associada ao clorambucila, com um ILD de 686 dias, sem atingir a mediana para SG. Não houve diferença no grupo de risco intermediário, independentemente do tratamento escolhido. Pacientes de risco intermediário podem não necessitar de tratamentos adjuvantes, mesmo na ausência de margens cirúrgicas livres.(AU)

Tratamento de tumor venéreo transmissível extragenital resistente à vincristina: quimioterapia antineoplásica e cirurgia reconstrutiva / Treatment of transmissible venereal extragenital tumor vincristine resistant: antineoplastic chemotherapy and reconstructive surgery

O Tumor Venéreo Transmissível (TVT) é uma neoplasia transmitida por células transplantáveis, com localização predominantemente venérea, podendo ainda ser encontrado em regiões extragenitais. Os agentes quimioterápicos são a opção mais utilizada no tratamento do TVT, sendo o sulfato de vincristina a droga de eleição e o sulfato de vimblastina uma alternativa de tratamento. O objetivo deste trabalho é relatar o tratamento de um caso de TVT nasal sem comprometimento genital, com destruição de tecidos moles e perda óssea, resistente à vincristina. Foi instituído inicialmente tratamento quimioterápico com sulfato de vincristina e posterior substituição por sulfato de vimblastina. Com a evolução do tratamento, houve regressão do tecido neoplásico e surgiram fístulas no local antes ocupado pelo tumor. Assim, quando já se havia obtido cura clínica e citologia negativa para células tumorais, realizou-se cirurgia reconstrutiva no palato e na maxila. Até o 180° dia de observação,o cão encontrava-se bem, com deformidade óssea na face mas sem alterações funcionais. Esse relato demonstra que o uso do sulfato de vimblastina foi um protocolo eficaz para o tratamento de TVT delocalização extragenital e que a utilização da quimioterapia antineoplásica seguida por cirurgia reconstrutiva é efetiva,capaz de proporcionar cura e qualidade de vida ao paciente(AU)

The transmissible venereal tumor (TVT) is a neoplasm transmitted by transplantable cells, with predominant venereal location, but also found in extragenital regions. Antineoplasic chemotherapy is the most used treatment for TVT. The vincristine sulphate is the drug of choice and vinblastine sulphate, an alternative chemotherapeutic agent. This work aims to report a case of nasal TVT without compromised genital areas, destroying tissue and bone loss, resistant to vincristine. Chemotherapic treatment with vincristine sulphate was initially established and subsequently replaced by vinblastine sulphate. After treatment, there was regression of the tumor and fistulas appeared on the areas previously occupied by the tumor. When clinical cure and negative cytology for tumor cells were achieved, reconstructive surgery was proceded on the palate and jaw. After 180 days of observation, the dog was healthy, presenting bone deformity in the face but without functional changes. This report demonstrates that vinblastine sulphate was an effective protocol for the treatment of extragenital TVT and that the use of anticancer chemotherapy followed by reconstructive surgery is effective, capable of inducing healing and quality of life for patients(AU)

Tratamento de tumor venéreo transmissível extragenital resistente à vincristina: quimioterapia antineoplásica e cirurgia reconstrutiva / Treatment of transmissible venereal extragenital tumor vincristine resistant: antineoplastic chemotherapy and reconstructive surgery

O Tumor Venéreo Transmissível (TVT) é uma neoplasia transmitida por células transplantáveis, com localização predominantemente venérea, podendo ainda ser encontrado em regiões extragenitais. Os agentes quimioterápicos são a opção mais utilizada no tratamento do TVT, sendo o sulfato de vincristina a droga de eleição e o sulfato de vimblastina uma alternativa de tratamento. O objetivo deste trabalho é relatar o tratamento de um caso de TVT nasal sem comprometimento genital, com destruição de tecidos moles e perda óssea, resistente à vincristina. Foi instituído inicialmente tratamento quimioterápico com sulfato de vincristina e posterior substituição por sulfato de vimblastina. Com a evolução do tratamento, houve regressão do tecido neoplásico e surgiram fístulas no local antes ocupado pelo tumor. Assim, quando já se havia obtido cura clínica e citologia negativa para células tumorais, realizou-se cirurgia reconstrutiva no palato e na maxila. Até o 180° dia de observação,o cão encontrava-se bem, com deformidade óssea na face mas sem alterações funcionais. Esse relato demonstra que o uso do sulfato de vimblastina foi um protocolo eficaz para o tratamento de TVT delocalização extragenital e que a utilização da quimioterapia antineoplásica seguida por cirurgia reconstrutiva é efetiva,capaz de proporcionar cura e qualidade de vida ao paciente

The transmissible venereal tumor (TVT) is a neoplasm transmitted by transplantable cells, with predominant venereal location, but also found in extragenital regions. Antineoplasic chemotherapy is the most used treatment for TVT. The vincristine sulphate is the drug of choice and vinblastine sulphate, an alternative chemotherapeutic agent. This work aims to report a case of nasal TVT without compromised genital areas, destroying tissue and bone loss, resistant to vincristine. Chemotherapic treatment with vincristine sulphate was initially established and subsequently replaced by vinblastine sulphate. After treatment, there was regression of the tumor and fistulas appeared on the areas previously occupied by the tumor. When clinical cure and negative cytology for tumor cells were achieved, reconstructive surgery was proceded on the palate and jaw. After 180 days of observation, the dog was healthy, presenting bone deformity in the face but without functional changes. This report demonstrates that vinblastine sulphate was an effective protocol for the treatment of extragenital TVT and that the use of anticancer chemotherapy followed by reconstructive surgery is effective, capable of inducing healing and quality of life for patients