Table 3 Univariate and multivariate cox analyses of PFS for ES-SCLC patients receiving ICIs

Gender

 Male

 Female

0.608 (0.390–0.946)

0.027*

0.586 (0.374–0.917)

0.019*

Age

 ≥ 60

 < 60

0.999 (0.707–1.410)

0.994

Smoking History

 Yes

 No

0.785 (0.552–1.116)

0.177

ECOG PS

  2

 ≥ 2

1.266 (0.845–1.898)

0.253

T stage

 ≤ 2

 > 2

1.603 (1.132–2.272)

0.008*

1.778 (1.240–2.550)

0.002*

N stage

 ≤ 2

 > 2

1.596 (1.121–2.270)

0.009*

1.436 (0.998–2.066)

0.051

M stage

 M1a

 M1b

1.096 (0.681–1.764)

0.705

 M1c

1.866 (1.706–3.293)

0.026*

1.956 (1.117–3.424)

0.019*

Type of ICIs

 PD-1

 PD-L1

1.718 (1.156–2.554)

0.007*

1.684 (1.120–2.533)

0.012*

Receiving TRT

 No

 Yes

0.651 (0.460–0.920)

0.015*

0.599(0.420–0.854)

0.005*

NO. of metastatic sites

 < 3

 ≥ 3

1.605 (0.917–2.808)

0.098

Liver metastases

 No

 Yes

1.192 (0.798–1.780)

0.391

Bone metastases

 No

 Yes

1.409 (0.964–2.060)

0.077

Brain metastases

 No

 Yes

1.039 (0.719–1.502)

0.838