Abstract
BACKGROUND: Immune checkpoint inhibitors (ICIs) have become a standard therapy in non-small cell lung cancer (NSCLC). Although lung cancer adjoining emphysematous bullae (Ca-ADJ) were reported to express higher programmed cell death-ligand 1 (PD-L1), the predictive impact of Ca-ADJ on the response to ICIs is unknown. METHODS: Two hundred and fifty-seven advanced or recurrent NSCLC patients treated with ICI monotherapy at Kyushu University Hospital and National Hospital Organization Kyushu Cancer Center were analyzed. To minimize the bias arising from the patients' background, adjusted Kaplan-Meier survival curves and Cox proportional hazards regression analyses using inverse probability of treatment weights (IPTW) were performed. RESULTS: Of the 257 patients, 55 had Ca-ADJ. Patients with Ca-ADJ were significantly associated with younger age (P = 0.0343), male sex (P = 0.0070), and smoking (P = 0.0080). The objective response rate of cases with Ca-ADJ was significantly higher than that of those without Ca-ADJ (36.4% vs. 20.8%, respectively; P = 0.0167). The disease control rate of cases with Ca-ADJ was also significantly higher than tumors without Ca-ADJ (63.6% vs. 47.5%, respectively; P = 0.0341). The IPTW-adjusted Kaplan-Meier curves showed that patients with Ca-ADJ had significantly longer progression-free survival (PFS) and overall survival (OS) than those without Ca-ADJ (P = 0.0407 and P = 0.0126, respectively). On IPTW-adjusted Cox analysis, Ca-ADJ was an independent predictor of PFS and OS (P < 0.0001 and P < 0.0001, respectively). CONCLUSIONS: Patients with Ca-ADJ may be good candidates for ICIs. These findings should be validated prospectively.