Transmissible Venereal Tumor Treated with Autohemotherapy

Abstract

Background: Transmissible venereal tumor (TVT) is a neoplasm of round cells, that affects exclusively the canine specie. The etiology of the tumor is unknown, but the hystiocitic hipothesis is the more accepted. It is transmitted principally by the venereal form, but the inplant of cells can cause the disease. The clinic signs of the neoplasia are typical and include tumoral friable mass (in shape of cauliflower), that bleed easily. The most common localization is external genitalia, but the tumor can appears in skin surface and other organs. TVT grows rapidly (progressive phase) after transplantation, followed by a static phase (without cell proliferation) and then may regress spontaneously (stage of regression). The regression of the neoplasia is associated with increased infiltration of T lymphocytes and macrophages in the tumor and characterized by increased apoptosis of tumor cells and fibrosis. The diagnosis of TVT is usually done by the physical aspect of the tumor, and confirmed by cytology or histopathology. TVT can be prevented by castration of the animals. The treatment of TVT is usually performed with vincristine, which has side effects, requires care in its application, and has a relatively high cost. Thus, new therapeutic low-cost alternatives are suggested, as is the case of autohemotherapy. The autohemotherapy technique consists of administration of autologous whole blood intramuscularly. In veterinary practice has been used successfully to treat bovine papillomatosis and other diseases. Probably the mechanism of action of autohemotherapy is to enhance organic immunity. This report aimed to evaluate the behavior of the transmissible venereal tumor in six dogs with naturally transplanted tumor after treatment with autohemotherapy. Materials, Methods & Results: Six adult bitches were clinically examined and all presented transmissible venereal tumor located in external genitalia, adquired by natural transmission. Cytological examination confirmed the diagnosis of TVT. The bitches were kept in kennels by one week before treatment, and it was not observed natural regression of tumor mass. After this time the animals were submitted to treatment with autohemotherapy, which consisted of application of autologous whole blood in the gluteal muscles, at dose of 10 mL. The applications were made weekly for seven weeks. All tumors were measured before and after autohemotherapy and, also weekly during the treatment. All tumors were friable and bleeding easily, multilobulated, nodulares, cauliflower-like shape, pale-pink to pale red, with surface smooth or irregular. In some animals there were signs of secondary infection. In general, the measurement of tumor ranged from 3.0 cm to 7.1 cm before of autohemotherapy. After treatment it was observed, macroscopically, a decrease of the tumoral mass in three dogs. Discussion: It was established as criterion for stopping treatment the time of seven weeks. Possibly if the treatment had been extended the regression could have been completed. Probably autohemotherapy increased immunity and, consequently, contributed to increase the body's resistance against TVT, producing regression of tumoral mass. Therefore, the autohemotherapy led to macroscopic partial regression of the tumor in 50% of animals subjected to this treatment, stimulating further research in this area.