Table 3. Simple and multiple linear regression analysis of circulating tumor cell number related factors in patient with lung adenocarcinoma.

	Simple linear regression					Multiple linear regression
	Unstandardized β (95% CI)	SE	Standardized β	p-value	R2	Unstandardized β (95% CI)	SE	Standardized β	VIF	p-value	R2
Primary tumor volume, per 10 cm3	0.272 (0.152 to 0.392)	0.057	0.736	<0.001	0.542	0.334 (0.147 to 0.521)	0.088	0.903	2.381	0.002	0.646
Sex (male as reference)	1.833 (−1.052 to 4.718)	1.378	0.292	0.199	0.085	2.014 (−0.243 to 4.271)	1.059	0.321	1.203	0.077
Age	0.134 (−0.058 to 0.327)	0.092	0.318	0.160	0.101	−0.086 (−0.267 to 0.095)	0.085	−0.203	1.710	0.328
Clinical stage	0.853 (−0.134 to 1.841)	0.472	0.383	0.086	0.147	−0.740 (−2.439 to 0.958)	0.797	−0.333	5.427	0.368
T stage	1.055 (0.020 to 2.090)	0.494	0.440	0.046	0.193	0.434 (−1.424 to 2.292)	0.872	0.181	5.587	0.626
N stage	0.202 (−0.915 to 1.319)	0.534	0.087	0.709	0.007	-	-	-	-	-
M stage	0.625 (−0.546 to 1.796)	0.560	0.248	0.278	0.062	-	-	-	-	-

CI: confidence interval; SE: standard error; VIF: variance inflation factor; T: tumor; N: node; M: metastasis.