Tumor blood flow modifying effect of electrochemotherapy with bleomycin

Background. Electrochemotherapy combines administration of the chemotherape utic drug, followed by application of electric pulses in order to increase drug delivery into the cells. The aim of this study was to determine the tu mor blood flow modifying effect of electrochemotherapy with bleomycin and c orrelate it with its antitumor effectiveness and extent of tumor necrosis. Materials and methods: Electrochemotherapy of SA-1 subcutaneous tumors in A /J mice was performed by application of electric pulses to the tumors, foll owing administration of bleomycin, and antitumor effectiveness determined b y tumor growth delay and tumor cures as well as extent of tumor necrosis. T umor blood modifying effect of therapy was evaluated by Patent blue stainin g technique and (RbCl)-Rb-86 extraction technique. Results: A good correlat ion of the two methods evaluating tumor blood flow, Patent blue staining an d the established (RbCl)-Rb-86 extraction technique was found (r = 0.944). Electrochemotherapy resulted in complete and permanent shut down of tumor b lood flow within 12 hours, which lasted for at least 5 days. The results on tumor blood flow, reduction compared well with the good antitumor effectiv eness of electrochemotherapy and with the extent of the necrosis in the tum ors. Conclusions: The results indicate that Patent blue staining technique is a simple and reliable method for estimation of tumor blood flow and that antitumor effectiveness of electrochemotherapy with bleomycin could be par tly attributed to its tumor blood modifying and anti-vascular effect.