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Programmed death-ligand 1 (PD-L1) expression may vary in different disease sites and at different time points of the disease course. We aimed to investigate PD-L1 heterogeneity and its usefulness as a predictive value for immune checkpoint inhibitor (ICI) therapy in patients with NSCLC.PD-L1 expression was analyzed in 1398 patients with NSCLC. The predictive value of PD-L1 for ICIs in 398 patients with metastatic NSCLC was assessed.PD-L1 was significantly associated with biopsy sites (p = 0.004). Adrenal, liver, and lymph node (LN) metastases had the highest PD-L1 expression as a continuous variable and at 1% or 50% cutoff. PD-L1 expression was lower in bone and brain metastases. Among 112 patients with two specimens tested, 55 (49%) had major changes in PD-L1 falling into different clinically relevant categories (1%, 1%-49%, ≥50%) at different time points. Previous ICI therapy was associated with significant decrease in PD-L1 compared with treatment-naive counterparts (p = 0.015). Patients with metastatic NSCLC treated with ICI (n = 398) were divided into three cohorts on the basis of biopsy sites: lung (n = 252), LN (n = 85), and distant metastasis (n = 61). Higher PD-L1 in lung or distant metastasis specimens was associated with higher response rate, longer progression-free survival, and overall survival. However, PD-L1 in LN biopsies was not associated with either response or survival.PD-L1 varies substantially across different anatomical sites and changes during the clinical course. PD-L1 from different biopsy sites may have different predictive values for benefit from ICIs in NSCLC.

Introduction Although most NSCLC patients with sensitizing epidermal growth factor receptor (EGFR) mutations have an impressive initial response, the vast majority has residual disease and develops acquired resistance after 9 to 14 months of EGFR tyrosine kinase (TKI) therapy. We recently reported a phase II trial showing that, for patients with molecularly unselected oligometastatic NSCLC who did not progress after first-line systemic therapy, local consolidation therapy (LCT) with surgery or radiation improved progression-free survival (PFS), compared with maintenance therapy alone. Herein, we report a retrospective analysis of LCT after TKI in patients with metastatic EGFR mutant NSCLC. Patients and Methods We identified patients with metastatic EGFR mutant NSCLC treated with TKI plus LCT or with TKI alone in the MD Anderson GEMINI (Genomic Marker-Guided Therapy Initiative) database and in our recently published LCT trial. PFS was compared between LCT plus TKI and TKI only treated patients using the log-rank test. Results We identified 129 patients with EGFR mutant NSCLC who were treated with first-line TKI and 12 that were treated with TKI followed by LCT. Among the 12 patients treated with TKI plus LCT, 8 patients had oligometastatic disease (defined as ≤ 3 metastases), and 4 patients had > 3 metastases. LCT regimens were hypofractionated radiotherapy or stereotactic ablative body radiotherapy for 11 patients and surgery for 1 patient. TKI followed by LCT resulted in a significantly longer PFS (36 months) compared with TKI alone (PFS, 14 months; log-rank P = .0024). Conclusions Our data suggests that first-line TKI plus LCT is a promising therapeutic strategy for patients with EGFR mutant NSCLC that merits further investigation.