Table 2.

Subgroup analyses of overall survival

Subgroups	N studies	Pooled HR	95% CI	P value (Heterogeneity between subgroups)
Brain imaging after initial CRT	4	0.94	0.74–1.18	0.0005
No brain imaging after initial CRT	3	0.70	0.57–0.85
Limited stage	5	0.82	0.71–0.94	0.67
Extensive stage	6	0.76	0.55–1.04
Any response to initial CRT	3	0.85	0.73–0.99	0.76
Complete response to initial CRT	4	0.80	0.52–1.22

HR hazard radio, CRT chemoradiotherapy, CI confidence interval, N number

Note: this table includes 5 limited stage studies and 6 extensive stage studies, because some trials included in this meta-analysis enrolled both limited and extensive stage small-cell lung cancer and we identified the HR values and pooled them with the individual subgroups