C77-18 Five-year Long-term Survivors and Clinical Characteristics in Advanced Non-small Cell Lung Cancer Treated With Immune Checkpoint Inhibitors: A Single-institution Real-world Study

Rationale Immune checkpoint inhibitors (ICIs) have demonstrated durable clinical benefits and long-term survival in patients with advanced non-small cell lung cancer (NSCLC) in clinical trials; however, data on long-term outcomes in real-world practice are not sufficient. The aim of this study was to elucidate the real-world outcomes and clinical characteristics of long-term survivors, particularly those who survived for more than five years, by clarifying the treatment realities of ICI therapy in patients with advanced NSCLC. Methods We retrospectively reviewed 183 patients with advanced non-small cell lung cancer (NSCLC) who received ICI therapy at our institution between August 2015 and August 2020. Overall survival (OS) and progression-free survival (PFS) were analyzed, and patients who survived ≥5 years were identified and compared with non-5-year survivors to explore clinical factors associated with long-term survival. Results Median follow-up was 17.1 months (range: 0.3 months - 119.5 months). The median OS was 18.2 months (95% CI: 13.0-23.1), and the 5-year OS rate was 20.1% (95% CI: 14.1-26.2%). The median PFS was 5.1 months (95% confidence interval [CI]: 3.7-6.4), with a 5-year PFS rate of 12.8% (95% CI: 7.7-17.9%). Among 183 patients, 25 achieved 5-year survival, and 11 of these remained recurrence-free after ICI therapy. Compared with non-5-year survivors, 5-year survivors experienced a significantly higher incidence of immune-related adverse events (irAEs) (68.0% vs. 34.2%, P = 0.002), whereas no significant differences were observed in age, sex, smoking history, performance status, histology, PD-L1 expression, EGFR mutation status, or baseline inflammatory markers including white blood cell count, lymphocyte count, and neutrophil-to-lymphocyte ratio, CRP level. Conclusions Even in real-world clinical practice, a subset of patients with advanced NSCLC can achieve long-term survival following ICI therapy, consistent with overall survival outcomes reported in pivotal clinical trials. The occurrence of irAEs appears to be associated with prolonged survival, suggesting that irAEs may serve as a clinical indicator of durable benefit from ICI therapy in advanced NSCLC.