Table 4 Univariate and multivariate cox analyses of OS for ES-SCLC patients receiving ICIs

Gender

 Male

 Female

0.802 (0.507–1.266)

0.343

Age

 ≥ 60

 < 60

0.661 (0.457–0.956)

0.028*

0.593 (0.408–0.862)

0.006*

Smoking History

 Yes

 No

0.835 (0.580–1.202)

0.332

ECOG PS

 < 2

 ≥ 2

1.208 (0.791–1.845)

0.382

T stage

 ≤ 2

 > 2

1.335 (0.929–1.920)

0.118

N stage

 ≤ 2

 > 2

1.249 (0.869–1.794)

0.230

M stage

 M1a

 M1b

1.994 (1.153–3.449)

0.014

2.051 (1.163–3.620)

0.013*

 M1c

3.516 (1.878–6.583)

< 0.001*

2.818 (1.437–5.527)

0.003*

Type of ICIs

 PD-1

 PD-L1

0.996 (0.676–1.466)

0.983

Receiving TRT

 No

 Yes

0.618 (0.428–0.892)

0.010*

0.670 (0.464–0.966)

0.032*

NO. of metastatic sites

 ≤ 2

 > 2

1.883 (1.070–3.314)

0.028*

1.836 (0.939–3.592)

0.076

Liver metastases

 No

 Yes

2.007 (1.364–2.953)

< 0.001

1.722 (1.160–2.558)

0.007*

Bone metastases

 No

 Yes

1.094 (0.726–1.648)

0.669

Brain metastases

 No

 Yes

1.247 (0.849–1.829)

0.260