Table 3. HR value for NSCLC subgroups according to histology subtypes and stages.

Subgroup	Studies	Patients	Fixed effect HR (95% CI)	Heterogeneity test	Ramdom effect HR (95% CI)
Adenocarcinoma	n=4	258	2.45 (1.66–3.64)	P=0.26
Nonsquamous carcinoma	n=3	158	2.47 (1.32–4.57)	P=0.90
Stage I	n=4	783	1.56 (1.26–1.93)	P=0.17
Stage I–II	n=4	437	1.16 (0.82–1.66)	P=0.21
Stage I–III	n=6	533	1.79 (1.40–2.28)	P=0.04	1.82 (1.26–2.64)