CONICET | Buscador de Institutos y Recursos Humanos

Background. Electrochemotherapy (ECT), a medical treatment widely used in human patients for tumor treatment,increases bleomycin toxicity by 1000 fold in the treated area with an objective response rate of around 80%. Despiteits high response rate, there are still 20% of cases in which the patients are not responding. This could be ascribed tothe fact that bleomycin, when administered systemically, is not reaching the whole tumor mass properly because ofthe characteristics of tumor vascularization, in which case local administration could cover areas that are unreachableby systemic administration.Patients and methods. We propose combined bleomycin administration, both systemic and local, using companionanimals as models. We selected 22 canine patients which failed to achieve a complete response after an ECTtreatment session. Eleven underwent another standard ECT session (control group), while 11 received a combinedlocal and systemic administration of bleomycin in the second treatment session.Results. According to the WHO criteria, the response rates in the combined administration group were: completeresponse (CR) 54% (6), partial response (PR) 36% (4), stable disease (SD) 10% (1). In the control group, these were:CR 0% (0), PR 19% (2), SD 63% (7), progressive disease (PD) 18% (2). In the combined group 91% objective responses(CR+PR) were obtained. In the control group 19% objective responses were obtained. The difference in the responserate between the treatment groups was significant (p < 0.01).Conclusions. Combined local and systemic bleomycin administration was effective in previously to ECT non respondingcanine patients. The results indicate that this approach could be useful and effective in specific populationof patients and reduce the number of treatment sessions needed to obtain an objective response.