Imatinib Mesylate for the Treatment of Canine Mast Cell Tumors: Assessment of the Response and Adverse Events in Comparison with the Conventional Therapy with Vinblastine and Prednisone.

Mast cell tumors (MCTs) are common neoplasms in dogs, and treatments for these diseases include surgery, polychemotherapy and targeted therapy with tyrosine kinase inhibitors. This study aimed to evaluate the response and the adverse events of treatment with imatinib mesylate (IM) compared to conventional therapy using vinblastine and prednisolone (VP) in canine cutaneous MCTs. Twenty-four dogs were included in the study; 13 animals were treated with IM and 11 with VP. Tumor tissue samples were submitted for histological diagnosis, grading and KIT immunostaining. The response to treatment was assessed by tomographic measurements according to VCOG criteria. Adverse events were classified according to VCOG-CTCAE criteria. The IM and VP groups had dogs with similar breeds, gender, ages, MCT localization, WHO stages and lymph node metastasis profiles. Most MCTs were grade 2/low and had KIT- patterns 2 and 3. The objective response rate (ORR) was significantly higher (30.79%) in the IM group then in VP group (9.09%). Adverse events (AE) in IM group were all grade 1, significantly different from VP. In conclusion, IM presented better ORR and less severe adverse events when compared to VP, representing a suitable option for the treatment of low-grade canine MCTs.

Thermographic assessment of skin and soft tissue tumors in cats.

OBJECTIVES: This study set out to determine the average temperature of skin and soft tissue tumors in cats using infrared thermography and to investigate correlations between thermographic findings and tumor type. Correlations between thermographic findings, histologic subtype and tumor grade were also investigated in cases of feline injection site sarcoma (FISS). METHODS: Thermographic images of normal skin and skin overlying neoplastic lesions were prospectively obtained. Following thermographic assessment, tumors were resected and submitted to histopathologic and immunohistochemical analysis. Mean temperatures detected in tumoral areas were compared between different tumor types and between FISSs of different histologic subtypes and grades. RESULTS: Thermograms obtained from 11 healthy cats and 31 cats presenting with skin and soft tissue tumors (eight benign and 23 malignant tumors, including 21 FISSs) were evaluated in this study. Thermal behavior varied widely in normal skin, as well as in skin overlying neoplastic lesions. Mean temperatures were significantly higher in malignant compared with benign tumors (35.4 ± 1.8ºC and 34.5 ± 1.7ºC respectively; P = 0.01), with a temperature above 34.7ºC being associated with malignancy (sensitivity 76%, specificity 80%; P = 0.01). Temperatures detected in FISS did not differ significantly according to histologic subtype (P = 0.91) or tumor grade (P = 0.46), or between primary and recurring tumors (P = 0.25). CONCLUSIONS AND RELEVANCE: Infrared thermography proved to be a sensitive and effective method for detection of temperature differences between malignant and benign skin and soft tissue tumors in cats. Thermographic assessment may contribute to diagnosis and prognostic estimation in feline oncologic patients.

Feline injection site sarcoma: computed-tomographic density and assessment of tumor dimensions by different methods / Sarcoma de aplicação felino: avaliação da densidade tomográfica e das dimensões tumorais por diferentes métodos

Feline injection site sarcoma is a malignant neoplasm with digitiform projections into muscular planes that are ill recognized during physical examination and may compromise tumor margin demarcation. This study compared tumoral size of 32 cats measured by different methods, and evaluated the CT density of 10 tumoral tissues (Hounsfield unit) based on histograms. Tumor axes were measured by physical examination and CT images. Larger craniocaudal axis measurements were obtained following multiplanar reconstruction of pre- and post-contrast CT images (p=0.049 and p=0.041 respectively); dorsoventral axis measurements taken from post-contrast CT images were also larger (p=0.010). Tumor volume estimates increased following contrast-enhancement. Histograms tended to produce two peaks: one in the fat and another in the soft tissue attenuation range. Multiplanar reconstructed post-contrast CT images provided clearer definition of tumor margins and more judicious determination of tumor size. A tendency of common FISS attenuation profile could be described.(AU)

O sarcoma de aplicação felino (SAF) é uma neoplasia maligna que geralmente apresenta projeções digitiformes para planos musculares adjacentes, dificilmente reconhecidos ao exame físico, o que pode comprometer a real identificação das suas margens. Este estudo comparou as dimensões tumorais de 32 SAFs mensurados por diferentes métodos (exame físico e por imagens de tomografia computadorizada) e avaliou a densidade tomográfica em unidades Hounsfield de 10 dessas neoplasias, com base em histogramas. As medidas no eixo craniocaudal foram maiores quando obtidas após reconstrução multiplanar de imagens tomográficas, tanto na fases pré como após administração de meio de contraste (p=0,049 e p=0,041, respectivamente). As medições tomográficas no eixo dorsoventral obtidas na fase pós-contraste também foram maiores, quando comparadas com as imagens pré-contraste (p=0,010). Estimativas do volume tumoral foram maiores após a fase contrastada. Os histogramas das densidades tumorais tenderam a produzir dois picos: o primeiro no intervalo de valores de densidade gordura e o segundo no intervalo correspondente a tecidos moles. As imagens tomográficas pós-contraste com reconstrução multiplanar demarcaram com mais clareza as margens do tumor e definiram de forma mais criteriosa o seu tamanho. Uma tendência de perfil de atenuação comum para o SAF pôde ser descrita com esse estudo.(AU)

Neurophysiological assessment of spinal cord injuries in dogs using somatosensory and motor evoked potentials.

Somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) are non-invasive neurophysiological tests that reflect the functional integrity of sensory and motor pathways. Despite their extensive use and description in human medicine, reports in veterinary medicine are scarce. SSEPs are obtained via peripheral stimulation of sensory or mixed nerves; stimulation induces spinal and cortical responses, which are recorded when sensory pathways integrity is preserved. MEPs can be obtained via transcranial electrical or magnetic stimulation; in this case, thoracic and pelvic limb muscle responses are captured if motor pathways are preserved. This review describes principles, methodology and clinical applicability of SSEPs and MEPs in companion animal medicine. Potential interferences of anesthesia with SSEP and MEP recording are also discussed.

Tomografia computadorizada de mastocitomas em cães: avaliação pré e pós-tratamento quimioterápico / Computed tomography of mast cell tumors in dogs: assessment before and after chemotherapy

Foram avaliados, por meio da tomografia computadorizada, 19 cães com mastocitomas tratados com quimioterapia. Aspectos como contorno, atenuação, realce pós-contraste e presença de clivagem com estruturas adjacentes foram avaliados. Aplicaram-se os critérios RECIST e a mensuração volumétrica das lesões para se avaliar a resposta ao tratamento. Quanto à atenuação, os mastocitomas se mostraram como lesões homogêneas ou heterogêneas, com tendência a limites definidos e contornos regulares e apresentaram realce moderado após administração do contraste iodado intravenoso. Os métodos RECIST e a mensuração volumétrica apresentaram uma excelente concordância na classificação da resposta terapêutica, fornecendo um bom parâmetro da resposta ao tratamento instituído. O exame de tomografia computadorizada se mostrou útil na delimitação do tumor e importante ferramenta no planejamento das margens cirúrgicas.

Nineteen dogs with mast cell tumors treated with chemotherapy were evaluated by computed tomography (CT). Were evaluated aspects related to contours, attenuation, post-contrast enhancement and presence of cleavage with adjacent structures. The RECIST criteria and volumetric measurement of lesions were performed to assess the response to treatment. The mast cell tumors presented a homogeneous or heterogeneous attenuation, presented more frequently a well delineated and regular contours and moderate enhancement after intravenous administration of the iodinated contrast media. The methods RECIST and volumetric measurements showed an excellent agreement to the classification of therapeutic response, providing a good parameter of the response to treatment. The CT examination proved to be useful in the delimitation of the tumor and an important tool for planning of surgical margins.