2.

Univariate and multivariate analyses of predictive factors for OS in patients with SCLC

Variables	Univariate*				Multivariate*
	HR	95% CI	P		HR	95% CI	P
OS, overall survival; SCLC, small-cell lung cancer; PS, performance score; CTC, circulating tumor cell; WBMTV, whole-body metabolic tumor volume; HR, hazard ratio; 95% CI, 95% confidence interval; *, Cox regression analysis with enter method; **, Cox regression analysis with stepwise method. CTCs at baseline and WBMTV before the initiation of therapy treatment are the only two predictors in the final Cox multivariate proportional-hazards model with stepwise method.
Age (median 59 years)	0.94	0.62−1.44	0.79		1.06	0.67−1.68	0.80
Sex (male vs. female)	1.01	0.66−1.54	0.97		1.00	0.98−1.02	0.90
PS (≤3)	1.57	1.02−2.39	0.39		0.81	0.18−3.70	0.75
Chemotherapy regimen utilized	0.94	0.54−1.93	0.94		1.08	0.57−2.07	0.81
CTCs at baseline	2.27	1.45−3.55	<0.01		4.73**	1.05−13.90	0.01
CTCs after one cycle of chemotherapy	1.61	1.24−2.10	<0.01		1.01	0.68−5.23	0.54
CTCs after four cycles of chemotherapy	0.82	0.59−1.13	0.22		1.00	0.57−3.67	0.57
WBMTV before treatment	1.91	1.24−2.95	<0.01		5.32**	2.10−11.93	<0.01