## 7 Future Perspectives  
Given the proven feasibility and safety of electroporation-based therapies, they should be considered methods with comprehensive perspectives for use in clinical practice. ECT is now mainly applied in treating cutaneous and subcutaneous tumors, and its effectiveness with limited side effects is well demonstrated in various studies. Their prevalent use is focused on palliative treatment in patients with inoperable tumors when other methods of treatment have failed [30; 128; 129; 33]. Prospectively, ECT may be implicit in deep-seated tumor treatment; however, further investigation is required. The treatment of internal tumors needs more effort and the development of clinical devices; however, it is beginning to develop optimistically in both ECT and IRE, which will be described below. Regarding technical requirements, the design of new electrodes may be valuable in clinical applications due to the challenging procedure of placement of ECT needles. One of the important considerations is the use of ECG during the procedure on internal tumors in the vicinity of the heart. The delivery of pulses should be synchronized with ECG [33; 130; 131]. The studies show no major changes in the heart rhythm and clinically irrelevant changes in the heart rate during ECT of colorectal liver metastases [132]. The entire tumor should be provided with the exact extent of EP, which can be accomplished with the support of real-time imaging. The application of suitable imaging may increase the effectiveness of ECT, because of the control of electrode adjustment and tumor coverage by the electric field [130]. Although promising results were achieved using in situ imaging methods, such as electrical impedance tomography (EIT) and magnetic resonance electrical impedance tomography (MREIT), these methods are currently too complex for EP. Interestingly, current density imaging (CDI) appeared to be a convenient method of monitoring the distribution of electric fields in electroporation-based therapies [63]. Further suggestions include the implementation of ECT in combination with other techniques, such as surgery. It could be utilized as a neoadjuvant in order to facilitate the removal of tumors challenging to reach. Another approach is based on combining ECT with other EP-based therapies, such as immunomodulatory GET, especially IL-12 GET [33; 131]. Although GET studiesmentioned previously have achieved auspicious results, further investigation is necessary for clinical deployment. Another prosperous EP-based therapy is irreversible electroporation (IRE). The use of IRE in clinical practice is developing, notably in treating liver and pancreatic cancer. Additionally, the efficacy of this method was recently clinically confirmed in the treatment of unresectable hilar cholangiocarcinoma and prostate cancer. Furthermore, IRE might be applied as a therapy for lung or brain cancer in the future [63]. Irreversible electroporation has been shown to be efficient as an ablative therapy in the treatment of locally advanced pancreatic cancer. It also may prove effective in combination with intraprocedural chemotherapy or immunotherapy, which could reinforce the treatment results [133]. Despite the encouraging outcomes, more prospective randomized controlled trials are necessary in order to establish the indications of treatment with IRE [134; 135]. The novel approach based on calcium electroporation, where high calcium concentrations are inserted into the cell with the use of EP and could prospectively be applied as a new efficient anticancer treatment method. The clinical studies demonstrated the systemic immune response after calcium electroporation and have asserted the safety and effectiveness of this method, which should encourage further investigations [136; 137]. The further utilization of EP is to enhance the transfer of DNA vaccination into the cell. It has been stated that EP increases the immunogenicity of DNA vaccines.