Lomustine for treatment of canine transmissible venereal tumor / Eficácia da lomustina no tratamento do tumor venéreo transmissível 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/m2 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.

O tumor venéreo transmissível canino (TVTC) é uma neoplasia transmissível de elevada casuística no Brasil. A quimioterapia com sulfato de vincristina é considerada o tratamento de escolha, mas a necessidade de aplicações semanais e acompanhamento hematológico, além dos custos, são obstáculos à adesão dos proprietários ao tratamento. A lomustina é um antineoplásico da classe dos agentes alquilantes e, por ser administrado por via oral, representa um opção de tratamento mais prática e menos onerosa para os proprietários de animais com neoplasias. O objetivo deste estudo foi avaliar a eficácia terapêutica da lomustina em cães acometidos por TVTC. Foram selecionados 12 cães com diagnóstico citopatológico de TVTC genital de ocorrência natural. Os cães foram submetidos ao protocolo experimental com administração de lomustina nas doses de 70 a 85 mg/m2 por via oral a cada 21 dias, totalizando no máximo dois ciclos de administração. Os animais foram reavaliados a cada sete dias até um máximo de +49 dias após a primeira dose de lomustina, para monitorar a regressão das lesões neoplásicas por meio de mensuração das lesões. Entre os 12 cães submetidos ao protocolo, 8/12 obtiveram remissão completa da neoplasia e foram considerados curados (66,6%), 1/12 tiveram resposta parcial ao tratamento (8,33%) e 3/12 tiveram doença estável (25%). Efeitos adversos importantes, como leucopenia neutrofílica grave, foram detectados em 3/12 cães (25%). O estudo clínico indicou que a lomustina pode ser uma opção de tratamento para TVTC.

A retrospective study of canine transmissible venereal tumour in Grenada, West Indies.

BACKGROUND: Canine transmissible venereal tumour (CTVT) is a naturally occurring neoplasia affecting dogs worldwide. Previous CTVT studies in Grenada were limited to case records of dogs with neoplastic conditions at a veterinary diagnostic laboratory. OBJECTIVES: The present retrospective study aimed to determine the occurrence and risk factors of CTVT in a wider population of owned dogs presented to a university-affiliated veterinary hospital between 2008 and 2018. METHODS: Data on the age, breed, gender, and gonadectomy status were retrieved from an electronic database and analyzed using logistic regression. RESULTS: Of the 7180 dogs presented during the period, 102 dogs (1.4%) were diagnosed with CTVT. A higher predisposition was observed in Grenadian pothounds (odds ratio [OR] = 22.8, 95% confidence interval [CI] 10.3-50.4; p < 0.001) and mixed-breed dogs (OR = 9.2, 95% CI 4.1-20.7; p < 0.001) in comparison to the purebreds. Neutered dogs (OR = 2.2, 95% CI 1.4-3.3; p < 0.001) were at an increased risk of CTVT than intact dogs. Age and gender were not identified as significant risk factors. CONCLUSIONS: The percentage of dogs with CTVT in this study represents a crude estimate of the CTVT prevalence in the owned dog population in Grenada. Further studies including both owned and free-roaming dogs are required for a more accurate estimation of the CTVT prevalence in the region. Our results indicate that breed and gonadectomy status are significant risk factors for the occurrence of CTVT in Grenada.

Evaluation of a Canine Transmissible Venereal Tumour Cell Line with Tumour Immunity Capacity but Without Tumorigenic Property.

INTRODUCTION: Canine transmissible venereal tumour (CTVT) is a sexually transmitted tumour affecting dogs worldwide, imposing a financial burden on dog owners. A stable culture cell line in continuous passages for >18 months has only been achieved once. The present study investigated a stable CTVT cell line isolated from a bitch and its potential as a vaccine. MATERIAL AND METHODS: A biopsy from a 2-year-old mongrel bitch with CTVT was obtained for histopathological confirmation and isolation of tumour cells. The isolated cells were cultured to passage 55 and characterised by flow cytometry, with karyotyping by GTG-banding and by PCR detection of myc S-2 and LINE AS1. The isolated CTVT cell line was also used as a preventive vaccine in a canine model. RESULTS: Histopathological analysis of the isolated tumour cells revealed typical CTVT characteristics. Constant proliferation and stable morphological characteristics were observed during culture. Phenotypic analysis determined the expression of HLA-DR+, CD5.1+, CD14+, CD45+, CD83+, CD163+, and Ly-6G-Ly-6C+. GTG-banding revealed a mean of 57 chromosomes in the karyotype with several complex chromosomal rearrangements. LINE-c-myc insertion in the isolated CTVT cell line at 550 bp was not detected. However, a 340-bp band was amplified. Isolated CTVT cell line inoculation at a concentration of 1×108 did not induce tumour growth in bitches, nor did a challenge with primary CTVT cells. CONCLUSION: The present study successfully identified and isolated a stable CTVT cell line that may be useful in CTVT prevention.

Tumor venéreo transmisible canino de presentación atípica. reporte de caso clínico / Canine transmissible venereal tumor of atypical presentation. clinical case report

RESUMEN Se describe el caso de un paciente canino macho entero, raza Bóxer, de ocho años de edad y 30 kg de peso vivo, que ingresó a consulta en el hospital Clínico Veterinario de la Universidad Santo Tomás, sede Santiago, por un aumento de volumen en el ojo derecho, signo clínico con un curso de dos meses de evolución que no respondió al tratamiento con prednisona oral (0,7 mg/kg, dos veces al día (BID), ni a dexametasona y tobramicina en ungüento oftálmico (1 gota, tres veces al día, TID). Al examen físico se observó una masa en el tercer párpado que desplazaba el ojo lateralmente, además de una masa que se palpaba en la base lateral del pene. Se realizó una ecografía ocular que indicó la presencia de una masa de aspecto irregular con parénquima heterogéneo y características neoplásicas en la zona medial del globo ocular derecho y una ecografía abdominal que permitió detectar una masa dorsal a la vejiga. Al realizar citología ecoguiada de las masas intraabdominal y ocular, bajo sedación, se constató una inflamación supurativa, necrosis y displasia epitelial en la masa periorbitaria sugerente de neoplasia, la cual no se pudo diagnosticar fehacientemente; por su parte, la citología de la masa intraabdominal indicó la presencia de Tumor Venéreo Transmisible (TVT). El tratamiento se inició con vincristina (ocho aplicaciones i.v. de 0,7 mg/m2 cada 7 días) lográndose remisión parcial. Ante una posible resistencia al efecto de la quimioterapia, se decidió modificar la terapia a doxorrubicina (30 mg/m2) la cual tuvo respuesta positiva alcanzando remisión completa con una aplicación única.

ABSTRACT An 8 years old, 30 kg live weight, intact male, Boxer breed, was presented at the Santo Tomas Veterinary Teaching Hospital because of a volume increase in his right eye of 2 months of duration; which didn't respond to oral prednisone (0.7 mg/kg, twice a day (BID), or dexamethasone and tobramycin in ophthalmic ointment (1 drop, three times a day, TID). On physical exam, a mass in the third eyelid and another on the base of the penis were noted. Besides that, ocular ultrasonography showed an irregular mass with neoplastic characteristics in the medial area of the eyeball and abdominal ultrasound indicated a mass dorsal to the bladder. Fine needle aspiration of the eye and abdomen masses were done under sedation; cytology of the tumor in the abdomen was compatible with transmissible venereal tumor (TVT) and in the eye the results were suppurative inflammation, necrosis and epithelial dysplasia. Neoplasia couldn't be rule out or confirmed. Initial treatment was started with vincristine (8 applications i.v of 0.7 mg/m2 every 7 days) obtaining a parcial remission; so, considering a possible resistance of the cells to this drug, doxorrubicin (30 mg/rrr2) was used. The patient had a positive response to doxorrubicin achieving complete remission with a single aplication.

Evaluation of a genetic assay for canine transmissible venereal tumour diagnosis in Brazil.

The canine transmissible venereal tumour (CTVT) is a transmissible cancer that is spread between dogs by the allogeneic transfer of living cancer cells. The infectious agents in CTVT are the living cancer cells themselves, which are transmitted between dogs during coitus. CTVT first arose several thousand years ago and the disease has a global distribution and is frequently observed in dogs from Brazil. We evaluated the utility of a LINE-MYC quantitative polymerase chain reaction for diagnosis of CTVT cases in Brazil. Our analysis indicated that the LINE-MYC rearrangement was detectable in all CTVT samples but not in their corresponding hosts. This genetic assay proves to be a useful tool for providing a definitive molecular diagnosis of CTVT, which presents with varying degrees of aggressiveness and invasiveness in different host dogs and can therefore be a diagnostic challenge in some specific cases.

Tumor venéreo transmisible con metástasis a un hemangioma esplénico en una perra / Transmissible venereal tumor with metastasis to a spleen hemangioma in a bitch

This report describes a case of transmissible venereal tumor (TVT) with metástasis to spleen in areas previously affected with a hemangioma in an adult mongrel stray bitch. In addition, the animal had seborrheic dermatitis associated with demodicosis, suggesting a deficient immune response. In Mexico, TVT is a common entity; however, metastases to internal organs are extremely rare. This is the first report of metastasis of TVT to an internal organ with a previous established tumour.

Este informe describe un caso del tumor venéreo transmisible (TVT) con metástasis en bazo y en áreas previamente afectadas con hemangioma en una perra adulta mestiza. Además, el animal tenía dermatitis seborreica asociada con dermodicosis, la cual sugería una respuesta inmune deficiente. En México, el TVT canino es una entidad común; sin embargo, las metástasis a los órganos internos son extremadamente raras. Este es el primer informe de metástasis de TVT a un órgano interno con un tumor previamente establecido.