Irreversible Electroporation in Locally Advanced Pancreatic Cancer: Potential Improved Overall Survival

Background. Locally advanced unresectable pancreatic adenocarcinoma (LAC) is characterized by poor survival despite chemotherapy and conventional radiation therapy. We have recently reported on the safety of using irreversible electroporation (IRE) for the management of LAC. The purpose of this study was to evaluate the overall survival in patients with LAC treated with IRE. Methods. A prospective, multi-institutional evaluation of 54 patients who underwent IRE for unresectable pancreatic cancer from December 2009 to October 2010 was evaluated for overall survival and propensity matched to 85 matched stage III patients treated with standard therapy defined as chemotherapy and radiation therapy alone. Results. A total of 54 LAC patients have undergone IRE successfully, with 21 women, 23 men (median age, 61 (range, 45-80) years). Thirty-five patients had pancreatic head primary and 19 had body tumors; 19 patients underwent margin accentuation with IRE and 35 underwent in situ IRE. Forty-nine (90 %) patients had pre-IRE chemotherapy alone or chemoradiation therapy for a median duration 5 months. Forty (73%) patients underwent post-IRE chemotherapy or chemoradiation. The 90 day mortality in the IRE patients was 1 (2 %). In a comparison of IRE patients to standard therapy, we have seen an improvement in local progression-free survival (14 vs. 6 months, p = 0.01), distant progression-free survival (15 vs. 9 months, p = 0.02), and overall survival (20 vs. 13 months, p = 0.03). Conclusions. IRE ablation of locally advanced pancreatic tumors remains safe and in the appropriate patient who has undergone standard induction therapy for a minimum of 4 months can achieve greater local palliation and potential improved overall survival compared with standard chemoradiation-chemotherapy treatments. Validation of these early results will need to be validated in the current multi-institutional Phase 2 IDE study.