Electrochemotherapy of liver tumors: Colorectal liver metastasis

Abstract

Electrochemotherapy (ECT) is a local treatment modality of malignant tumors. It uses electroporation which significantly increases the concentration of bleomycin or cisplatin in cells and thereby also their cytotoxicity. ECT is currently mostly used for the treatment of the cutaneous tumors, predominantly for melanoma; however, other tumors, including colorectal liver metastases, also showed high response rate. Further development of ECT is aimed at the treatment of the deepseated tumors with different technological approach among which liver tumors represent a typical model. ECT of the colorectal liver metastases is performed during open surgery, by inserting the electrodes with fixed or variable geometry into and around the tumor to cover the whole tumor area and the margin of normal tissue with a sufficiently intensive electric field according to the individualized treatment plan. Electric pulses, synchronized with the electrocardiogram, are delivered after intravenous administration of bleomycin (15,000 IU/m2). Pathological analysis revealed that non-ECT-treated metastases were associated with a significantly higher percentage of residual vital tumor tissue than ECT-treated metastases. On average, electrochemotherapy-treated metastases had 9.9 12.2% (AM SD) viable tissue and those without electrochemotherapy 34.1 22.5% ( p = 0.001, t-test). Radiologically, 85% of metastases showed complete response and 15% partial response. More importantly, also metastases located in the near vicinity of the major vessels responded equally good as those located far from the major vessels. No immediate (intraoperative) and/or postoperative serious adverse events were observed.