## 5 Conclusions  
The cases presented in this study revealed that the IRE protocol can be applied for the treatment of LAPC. The IRE procedure with calcium ion administration was also effective (more extended tumor necrosis was visible), despite complications after the surgery. It is difficult to state whether the acute pancreatitis that developed in the first case and pancreatic fistula in the second case were caused by the IRE procedure alone or administration of calcium ions or too high concentration, and to what extent pancreatitis influenced the occurrence of necrosis. Therefore, the cause of pancreatitis and the reason for the larger necrosis visible in the imaging of the abdominal cavity are unknown. It remains unclear whether the administration of calcium ions is safe for the pancreas, which is a chimeric and delicate organ, and it requires studies on the animal model. However, this treatment option should be considered for chemoresistance patients. The determination of calcium ion concentration necessary for this procedure and the time of administration (administration after the IRE procedure seems to be safer) also requires further study. It seems that the administration of calcium ions may increase the effectiveness of the procedure itself.  
In the first case, the general condition of the patient delayed the initiation of systemic treatment, which is a standard method of palliative pancreatic cancer treatment.  
The implications of this procedure in terms of overall survival of the patient remain unknown because it is a case report. In the first case, overall survival was 9 months from diagnosis, but in the second case, it is already 21 months, and the patient is in very good condition (WHO 0). It is hard to say that this is due to calcium electroporation or electrochemotherapy (patient received an intravenous dose of cisplatin during the IRE procedure), but it seems promising for longer survival in palliative pancreatic cancer patients. Considering these two cases, it is certain that electroporation and systemic treatment should be used together as in the second case (the first one resigns twice from the CTH because of poor tolerance).  
Summarizing, we conclude that IRE is a safe method for treating LAPC. The administration of calcium ions before the procedure changes tissue conductivity; therefore, calcium ions should be delivered after the IRE procedure rather than before it. Furthermore, the administration of calcium ions may increase the effectiveness of IRE for treating pancreatic cancer. However, further clinical studies are required to determine the influence and concentration of calcium ions in combination with the ablation procedures for treating pancreatic cancer to confirm the hypothesis about the safeties of this method, but calcium electroporation seems to be efficient in pancreatic cancer treatment.  
Conceptualization, J.R.-R. and J.K.; methodology, J.R.-R., M.P., M.G.; formal analysis and investigation, J.R.-R. and J.K.; resources, W.K.; data curation, M.P., M.G.; writing--original draft preparation, J.R.-R.; writing--review and editing, J.K., visualization, M.P., M.G.; supervision, J.R.-R. and J.K.; project administration, W.K.; funding acquisition, W.K. All authors have read and agreed to the published version of the manuscript.  
This work was performed in the scope of the project of Polish National Science Centre from the project SONATA BIS 6 2016/22/E/N25/00671 (PI: [PERSON]) and the funds of Medical University Hospital from Wroclaw SUB. A190.19.026 (PI: [PERSON]).  
The authors declare no conflict of interest.