Neuron-specific enolase predicts the prognosis in advanced small cell lung cancer patients treated with first-line PD-1/PD-L1 inhibitors

There has been no effective biomarker for small cell lung cancer (SCLC) patients with first-line immune checkpoint inhibitors (ICIs) treatment. The predictive value of neuron-specific enolase (NSE) in this cohort remains unclear. The medical records of 254 consecutive SCLC patients receiving programmed cell death receptor-1/programmed cell death-ligand 1 (PD-1/PD-L1) inhibitors were compiled from January 2015 to October 2020 in Chinese PLA General Hospital. Survival analysis was performed to explore the prognostic role of NSE at baseline and 3 weeks post treatment. One hundred two advanced SCLC patients treated with first-line PD-1/PD-L1 inhibitors were enrolled in this study. Normal baseline NSE levels were correlated with significantly prolonged progression-free survival (PFS, median: 8.7 vs 4.7 months, P = .006) and overall survival (OS, median: 23.8 vs 15.2 months, P = .014) compared with elevated baseline NSE levels, so as for normal NSE levels at 3 weeks with prolonged PFS (median PFS: 8.4 vs 4.5 months, P = .0002) and OS (median OS: 23.3 vs 7.4 months, P < .0001). Intriguingly, elevated NSE levels at 3 weeks were associated with shorter PFS (median PFS: 4.5 vs 5.8 months, P = .04) and OS (median OS: 5.5 vs 14.7 months, P < .0001) compared with normal NSE levels in the elevated baseline NSE subgroup. Most subgroup analyses stratified by clinical characteristics confirmed the prognostic value of baseline NSE level. Elevated NSE levels at baseline and 3 weeks were associated with worse prognosis in advanced SCLC patients receiving first-line ICIs treatment. NSE level might be applied as a useful prognostic tool for SCLC patients with immunotherapy.