1446PImmunological impact of surgery in NSCLC patients

Abstract Background Immune checkpoint inhibitors (ICI) improve survival in patients with advanced non-small cell lung cancer (NSCLC) and have become one of standard therapy. It was demonstrated that nivolumab therapy for resectable NSCLC patients prior to surgery resulted in major pathological responses in 40% of the patients. On the other hand, adjuvant nivolumab therapy for melanoma resulted in longer recurrence-free survivals. Thus, it is still uncertain which host immunological status is appropriate for ICI therapy, before or after surgery. In this study, we examined the peripheral blood, and tumor tissues to elucidate immunological impact of surgery in NSCLC patients. Methods The present study comprised of 20 surgically resectable early (stage I, II, or IIIA) NSCLC patients in Saitama Medical University International Medical Center. Peripheral blood samples were collected before and after surgical resection of NSCLC. PBMCs were analyzed with LSR FortessaTM. Results Interestingly, more effector memory (EM) CCR7-CD45RA- CD8+ T cells and CD62Llow CD4+ T cells were observed in early stage NSCLC patients, compared with stage IV NSCLC patients. Significant decrease of the percentages of EM CD8+ T cells (P = 0.0045) and CD62Llow CD4+ T cells (P  Conclusions After surgical removal of lung cancer, EM type T cells were converted to CM type T cells. It seems that surgery may have negative influence for innate immunity. Because PD-1 blockade therapy only activates primed effector T cells, the immunological status before surgery seems more appropriate for ICI therapy. Legal entity responsible for the study Saitama Medical University International Medical Center. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.