Table 3.

Univariate and multivariate Cox proportional hazards analysis of CSS for patients with metastatic small cell lung cancer in the SEER database

Variables	Univariate analysis	P value	Multivariate analysis	P value
	HR (95%CI)		HR (95%CI)
Gender		<0.001		<0.001
Male	1.000		1.000
Female	0.901 (0.867-0.937)		0.896 (0.862-0.932)
Age		<0.001		<0.001
≤60	1.000		1.000
>60	1.296(1.240-1.353)		1.127(1.078-1.178)
Race		<0.001
Caucasian	1.000		1.000
Black	0.928(0.866-0.994)	0.033	0.930(0.867-0.996)	0.039
Others	0.831(0.749-0.922)	<0.001	0.812(0.730-0.902)	<0.001
Grade		<0.001		0.037
I	1.000		1.000
II	2.507(1.025-6.132)	0.044	3.261(1.331-7.988)	0.010
III	2.297(1.145-4.609)	0.019	2.549(1.269-5.122)	0.009
IV	2.368 (1.182-4.744)	0.015	2.721 (1.357-5.458)	0.005
Unknown	2.433 (1.217-4.867)	0.012	2.639 (1.318-5.285)	0.006
T stage		<0.001		<0.001
T1	1.000		1.000
T2	1.127 (1.057-1.202)	<0.001	1.109 (1.040-1.182)	0.002
T3	1.095 (1.022-1.172)	0.010	1.135 (1.059-1.216)	<0.001
T4	1.127(1.057-1.203)	<0.001	1.185(1.110-1.265)	<0.001
Tx	1.316(1.243-1.394)	<0.001	1.233(1.164-1.306)	<0.001
Surgery of Metastases		<0.001		<0.001
No	1.000		1.000
Yes	0.727(0.655-0.907)	<0.001	0.772(0.692-0.860)	<0.001
Unknown	1.271(0.912-1.771)	0.157	0.822(0.588-1.148)	0.250
Radiotherapy		<0.001		<0.001
Yes	1.000		1.000
No	2.884(2.496-3.333)	<0.001	1.576(1.361-1.826)	<0.001
Unknown	1.672(1.606-1.742)	<0.001	1.321(1.264-1.381)	<0.001
Chemotherapy		<0.001		<0.001
No	1.000		1.000
Yes	0.281(0.269-0.293)		0.295(0.282-0.309)
Metastasis site		<0.001		<0.001
Brain	1.000		1.000
Bone	0.956(0.886-1.032)	0.247	1.032(0.954-1.117)	0.432
Liver	1.417(1.324-1.517)	<0.001	1.259(1.175-1.348)	<0.001
Lung	0.966(0.883-1.057)	0.450	0.880(0.804-0.963)	0.006
multisite	1.378(1.293-1.468)	<0.001	1.405(1.319-1.498)	<0.001