Table 2.

Multivariate Analysis of Progression-Free Survival

Characteristics	Progression-Free Survival
	HR (95% CI)	p Value
Age (≥75 vs. <75 y)	1.18 (0.77–1.74)	0.428
Sex (male vs. female)	1.37 (0.91–2.10)	0.137
Smoking status (never vs. current or former smoker)	1.34 (0.82–2.16)	0.246
ECOG PS (0–1 vs. 2–3)	0.37 (0.21–0.74)	0.007
PD-L1 expression (≥50% vs. <50%)	0.57 (0.38–0.83)	0.003

CI, confidence interval; ECOG PS, Eastern Cooperative Oncology Group performance status; HR, hazard ratio; PD-L1, programmed death-ligand 1.