Electrochemotherapy: technological advancements for efficient electroporation-based treatment of internal tumors.

Electrochemotherapy, a combination of high voltage electric pulses and of an anticancer drug, has been demonstrated to be highly effective in treatment of cutaneous and subcutaneous tumors. Unique properties of electrochemotherapy (e.g., high specificity for targeting cancer cells, high degree of localization of treatment effect, capacity for preserving the innate immune response and the structure of the extracellular matrix) are facilitating its wide spread in the clinics. Due to high effectiveness of electrochemotherapy in treatment of cutaneous and subcutaneous tumors regardless of histological origin, there are now attempts to extend its use to treatment of internal tumors. To advance the applicability of electrochemotherapy to treatment of internal solid tumors, new technological developments are needed that will enable treatment of these tumors in daily clinical practice. New electrodes through which electric pulses are delivered to target tissue need to be designed with the aim to access target tissue anywhere in the body. To increase the probability of complete tumor eradication, the electrodes have to be accurately positioned, first to provide an adequate extent of electroporation of all tumor cells and second not to damage critical healthy tissue or organs in its vicinity. This can be achieved by image guided insertion of electrodes that will enable accurate positioning of the electrodes in combination with patient-specific numerical treatment planning or using a predefined geometry of electrodes. In order to be able to use electrochemotherapy safely for treatment of internal tumors located in relative proximity of the heart (e.g., in case of liver metastases), the treatment must be performed without interfering with the heart's electrical activity. We describe recent technological advances, which allow treatment of liver and bone metastases, soft tissue sarcomas, brain tumors, and colorectal and esophageal tumors. The first clinical experiences in these novel application areas of electrochemotherapy are also described.

Electrochemotherapy: a new technological approach in treatment of metastases in the liver.

Electrochemotherapy is now in development for treatment of deep-seated tumors, like in bones and internal organs, such as liver. The technology is available with a newly developed electric pulse generator and long needle electrodes; however the procedures for the treatment are not standardized yet. In order to describe the treatment procedure, including treatment planning, within the ongoing clinical study, a case of successful treatment of a solitary metastasis in the liver of colorectal cancer is presented. The procedure was performed intraoperatively by inserting long needle electrodes, two in the center of the tumor and four around the tumor into the normal tissue. The insertion of electrodes proved to be feasible and was done according to the treatment plan, prepared by numerical modeling. After intravenous bolus injection of bleomycin the tumor was exposed to electric pulses. The delivery of the electric pulses did not interfere with functioning of the heart, since the pulses were synchronized with electrocardiogram in order to be delivered outside the vulnerable period of the ventricles. Also the post treatment period was uneventful without side effects. Re-operation of the treated metastasis demonstrated feasibility of the reoperation, without secondary effects of electrochemotherapy on normal tissue. Good antitumor effectiveness with complete tumor destruction was confirmed with histological analysis. The patient is disease-free 16 months after the procedure. In conclusion, treatment procedure for electrochemotherapy proved to be a feasible technological approach for treatment of liver metastasis. Due to the absence of the side effects and the first complete destruction of the treated tumor, treatment procedure for electrochemotherapy seems to be a safe method for treatment of liver metastases with good treatment effectiveness even in difficult-to-reach locations.

Prognostic value of E-cadherin expression in thyroid follicular carcinoma.

AIMS: To evaluate the expression of E-cadherin, its association with various clinicopathological features and its possible relation with distant metastasis-free survival (DMFS) in follicular carcinoma of the thyroid. METHODS: E-cadherin expression was assessed immunohistochemically in sections from paraffin embedded tissues in a group of 54 patients with follicular carcinoma and its variants who were followed for a median of 7.25 years. RESULTS: Reduced E-cadherin expression, defined as <90% of cells showing membrane positivity, was found in 15 tumours and was significantly associated with widely invasive growth, insular morphology and lesser degree of differentiation, but was not related to patient sex and age or tumour size. In univariate analysis, DMFS was significantly worse in male patients (P<0.03), widely invasive tumours (P=0.0002), moderately/poorly differentiated tumours (P<0.05) and tumours showing reduced E-cadherin expression (P=0.0001). In multivariate analysis, the degree of invasiveness and E-cadherin expression were the only independent prognostic factors. Among widely invasive cases, those with reduced E-cadherin expression had significantly worse DMFS than those with preserved expression. CONCLUSIONS: Our findings suggest that E-cadherin expression could be used as a prognostic marker in widely invasive follicular carcinomas of the thyroid. Larger studies are needed to assess its prognostic value in the group of minimally invasive carcinomas.