Table 2.

Correlation coefficient between each pair of the variables selected by univariate analysis.

Correlation coefficients	ECOG PS	Bone metastasis	Pretreatment LIPI	ICI drugs	Stage	Liver metastasis
ECOG PS	–	0.117	0.161	-0.185	0.150	0.351
Bone metastasis	0.117	–	0.347	0.085	0.379	0.415
Pretreatment LIPI	0.161	0.347	–	-0.026	0.160	0.310
ICI drugs	-0.185	0.085	-0.026	–	-0.043	0.128
Stage	0.150	0.379	0.160	-0.043	–	0.333
Liver metastasis	0.351	0.415	0.310	0.128	0.333	–

ECOG PS, Eastern Cooperative Oncology Group Performance Status; LIPI, lung immune prognostic index; ICI, immune checkpoint inhibitor.