Table III.

Multivariate analysis of overall survival.

Variables	Standard error	Hazard ratio	95% CI	P-value
Grouping	0.359	1.419	0.207–0.848	0.016
Predicted FEV1	0.247	1.680	1.036–2.724	0.035
N downstaging	0.675	2.305	1.423–5.074	0.013
Skip N2 metastasis	0.253	2.104	1.281–3.466	0.003

FEV1; forced expiratory volume in 1 sec; CI, confidence interval.