Table 1. Characteristics of all included studies in the meta-analysis.

First Author	Year	Country	Ethnicity	Age (range and median)	Sample Size	Follow-up (months)	Median OS (months)	Cut off	Clinical stage	Survival analysis	Outcome	NOS
Ju[20]	2018	China	Asian	NR	154	NR	NR	3.70	L+E	M	OS	8
Wang (1)[21]	2017	China	Asian	31–83	172	NR	19.18	3.86	L+E	M	OS	7
Huang[22]	2016	China	Asian	31–88	112	NR	NR	4.50	L+E	M	OS	8
Zhang[23]	2017	China	Asian	59 (30–78)	265	NR	16	4.0	L+E	M	OS	8
Wang (2)[24]	2016	China	Asian	62 (28–79)	153	NR	23.3	3.20	L+E	M	OS/PFS	8
Wang (3)[25]	2017	China	Asian	NR	181	NR	NR	3.60	L+E	M	OS	8
Bernhardt[26]	2018	Germany	Caucasian	64 (37–93)	350	NR	20	4.0	L	U	OS	7
Murray[27]	2014	UK	Caucasian	61.6 (38.3–77.4)	52	26.1	21.1	5	L	M	OS	6
Hong[28]	2015	China	Asian	56 (16–84)	919	NR	10.4	5	L+E	M	OS	8
Sakin[29]	2019	Turkey	Caucasian	61 (35–83)	113	6 (1–33)	NR	3	E	M	OS	8
Suzuki {1}[30]	2018	USA	Caucasian	63	252	NR	11.0	4.0	E	M	OS	8
Wang (4)[31]	2014	China	Asian	NR	114	NR	14	3	L+E	M	OS	8
Xie ①[32]	2015	China	Asian	68 (27–91)	555	10.8	NR	5	E	M	OS	8
Xie ②[32]	2015	China	Asian	68 (27–91)	383	10.8	NR	5	L	M	OS	8
Suzuki {2}[33]	2018	USA	Caucasian	65	122	NR	16.6	2.9	L	M	OS	7
Käsmann[34]	2017	Germany	Caucasian	NR	65	NR	20	4.0	L	M	OS	8
Deng[35]	2017	China	Asian	58 (24–81)	320	39.1	13.8	2.65	L+E	M	OS/PFS	8
Lohinai[36]	2019	Hungary	Caucasian	58	155	NR	NR	2.258	L+E	M	OS	7
Wang (5)[37]	2019	China	Asian	58(39–71)	228	46	20	2.3	L+E	M	OS/PFS	8
Li[38]	2019	China	Asian	NR	160	NR	NR	2.32	L+E	M	OS	7
Liu[39]	2019	China	Asian	59	316	NR	11	2.68	L+E	M	OS	8

(1)–(5): different authors and different studies; {1}–{2}: the same author but different studies; ①–②: the same author and the same study; L: limited stage; E: extensive stage; M: multivariate; U: univariate; NR: not reported; NOS: Newcastle-Ottawa scale