Prognostic role of pretreatment serum ferritin concentration in lung cancer patients: A meta-analysis

Table 1 Basic characteristics of included studies

Ref.	Country	Sample size	Tumor type	TNM stage	Treatment	Cutoff value of ferritin (ng/dL)	NOS				Endpoint
							Selection	Comparability	Outcome	Overall
Milman et al[17], 1991	Denmark	31	SCLC	Limited and advanced	Non-surgery	400	3	0	3	6	OS
Ferrigno et al[18], 1992	Italy	168	LC	I-IV	Mixed	236	4	0	2	6	OS
Milman et al[19], 2002	Denmark	90	NSCLC	I-IV	Mixed	300	4	0	3	7	OS
Milman et al[19], 2002	Denmark	25	SCLC	Limited and advanced	Mixed	300	3	0	3	6	OS
Erbaycu et al[20], 2008	Turkey	41	LC	I-IV	Mixed	220	3	0	3	6	OS
Zhao et al[21], 2014	China	69	LC	IV	Non-surgery	NR	4	0	3	7	OS
Xie et al[22], 2018	China	72	SCLC	Limited and advanced	NR	NR	4	0	3	7	OS
Lee et al[23], 2019	Republic of Korea	138	NSCLC	IIIB-IV	Non-surgery	200	4	0	3	7	OS
Ma et al[24], 2019	China	393	NSCLC	I-III	NR	382.65	4	0	3	7	OS
Sun[25], 2020	China	72	NSCLC	III-IV	Non-surgery	Male: 200, female: 150	3	0	3	6	OS
Ji et al[26], 2021	China	69	NSCLC	IIIB-IV	Non-surgery	311.1	3	0	3	6	OS
Xiao[27], 2021	China	86	SCLC	NR	NR	NR	3	0	3	6	OS
Zhu[28], 2021	China	400	LC	I-IV	NR	114.1	4	0	3	7	OS

LC: Lung cancer; SCLC: Small cell lung cancer; NSCLC: Non-small cell lung cancer; NR: Not reported; OS: Overall survival; NOS: Newcastle Ottawa Scale.

Table 2 Results of meta-analysis

	No. of studies	HR	95%CI	P value	I2 (%)	Pheterogeneity
Overall survival	12 (17-28)	1.09	1.03-1.15	0.004	86.5	< 0.001
Country
Non-China	5 (17-20, 23)	1.61	1.27-2.03	< 0.001	0.0	0.760
China	7 (21, 22, 24-28)	1.06	1.00-1.12	0.042	91.5	< 0.001
Tumor type
SCLC	4 (17, 19, 22, 27)	1.99	0.74-5.35	0.175	90.7	< 0.001
LC	4 (18, 20, 21, 28)	1.39	1.09-1.77	0.008	0.0	0.666
NSCLC	5 (19, 23-26)	1.03	0.98-1.07	0.281	86.2	< 0.001

HR: Hazard ratio; CI: Confidence interval; SCLC: Small cell lung cancer; LC: Lung cancer; NSCLC: Non-small cell lung cancer.