Immunomodulatory Effect after Irreversible Electroporation in Patients with Locally Advanced Pancreatic Cancer

He, Chaobin; Wang, Jun; Sun, Shuxin; Zhang, Yu; Li, Shengping

In the next step of the present study, we evaluated the prognostic factors for OS and PFS and showed that elevation of CD8 + T cell was associated with favourable OS and PFS in LAPC patients after IRE. This can be explained by a stimulated host immune response which might limit the progression and invasion of tumor, and therefore, better survival was achieved. This can be proved by previous studies in which strong relationships were observed between immune toxicity and metastasis [31] . Metastases were more frequently observed in patients with lower density of immune effector cells [32] , which was in accordance with our results. Furthermore, the predictive power of the alteration of several immune cells and inflammation-based indexes were compared in this study. It was demonstrated that the alteration of CD8 + T cell was superior to other indexes. In addition, as a robust and economic method, the alteration of CD8 + T cell can be obtained from peripheral blood sample fast and easily and can be used widely in clinical practice. Although there was a correlation between immune cells and inflammationbased indexes [27] , the alteration of CD8+ T cell could still provide additional prognostic value in patients with the same levels of inflammation-associated situation. Maybe they can be considered as complements for predicting the prognosis of LAPC patients after IRE. However, a slightly lower value of AUC for CD8+ T cell in PFS prediction suggested that, compared with PFS, maybe OS was affected more greatly by the changes of immune system. Different from tumorinfiltrating CD8 + T cells, which were shown to play more important role in determine local progression, compared with prognosis [33, 34] . LAPC is a systemic disease other a local disease. In the present study, peripheral blood samples were collected before and after IRE treatment and were analyzed by flow cytometry for CD8 + T cells. Therefore, it was thought that the human immune system played a more important role in long-term survival than in local control. Similar to the present study, in the study conducted by Chen et al. [35] , it was shown that alteration of CD8 + T cells was the only independent prognostic factor for OS, other than PFS. This may partly explain the different impact on survival from the alteration of CD8 + T cells. However, this difference needed to be further explored by further studies.