Is neoadjuvant immunotherapy necessary in patients with programmed death ligand 1 expression-negative resectable non-small cell lung cancer? A systematic review and meta-analysis

Objectives: The aim of this study was to investigate the clinical benefit and necessity of neoadjuvant programmed cell death (or ligand) (PD-(L)1) blockades in resectable non-small cell lung cancer (NSCLC) patients with negative PD-L1 expression. Materials and methods: Randomized control trials (RCTs) that compared event-free survival (EFS), overall survival (OS), major pathological response (MPR), and/or pathological complete response (pCR) between neoadjuvant chemo-immunotherapy (nCIT) and neoadjuvant chemotherapy (nCT) for patients with resectable NSCLC stratified by PD-L1 expression were eligible for inclusion in the study. Data regarding the pathological response and EFS were evaluated by the odds ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) using random and fixed models. Results: A total of six RCTs involving 3,194 patients with resectable NSCLC with or without neoadjuvant immunotherapy were included. Compared with nCT alone, nCIT significantly improved pCR (18.3 % vs. 3.0 %; OR, 5.64; 95 % CI, 3.22-9.89; P < 0.001), MPR (38.9 % vs. 15.5 %; OR, 3.57; 95 % CI, 2.10-6.05; P < 0.001), and EFS (HR, 0.75; 95 % CI, 0.62-0.90; P = 0.002) in PD-L1 <1 % NSCLC patients. In addition, PD-L1 >= 1 % was associated with higher rates of pCR (32.8 % vs. 18.3 %; OR, 2.28; 95 % CI, 1.40-3.73; P = 0.001) and MPR (53.9 % vs. 38.9 %; OR, 1.84; 95 % CI, 1.22-2.79; P = 004) and longer EFS (HR, 0.44 vs. 0.75) in the setting of nCIT compared with PD-L1 <1 %. nCIT improved only OS in NSCLC patients with PD-L1 >= 1 % but not in patients with PD-L1 <1 %. Conclusions: The use of nCIT should be recommended for resectable NSCLC patients with negative PD-L1 expression, as nCIT significantly improved the pathological response and EFS in these patients. The benefit to PD-L1-negative patients treated with nCIT on OS remains to be validated.