Table 2 Selected factors in the training cohort for building the model by univariate and multivariate Cox regression analysis

Age

 <50

Reference

Reference

 50 ~ 59

0.352(0.297 ~ 0.417)

 < 0.001

1.279(1.065 ~ 1.535)

 < 0.001

 60 ~ 69

0.589(0.541 ~ 0.641)

 < 0.001

1.482(1.245 ~ 1.763)

0.008

 ≥ 70

0.724(0.681 ~ 0.77)

 < 0.001

1.999(1.681 ~ 2.377)

 < 0.001

Sex

 Female

Reference

Reference

 Male

0.602(0.57 ~ 0.637)

 < 0.001

1.368(1.292 ~ 1.448)

 < 0.001

TumorType

 Adenocarcinoma

Reference

Reference

 Squamous cell carcinoma

4.559(3.661 ~ 5.678)

 < 0.001

1.13(1.06 ~ 1.205)

 < 0.001

 Adenosquamous carcinoma

7.951(6.371 ~ 9.924)

 < 0.001

1.227(1.051 ~ 1.432)

 < 0.001

 Large cell carcinoma

8.139(6.258 ~ 10.586)

 < 0.001

1.494(1.263 ~ 1.767)

 < 0.001

 Others

9.402(7.228 ~ 12.231)

 < 0.001

0.312(0.248 ~ 0.392)

 < 0.001

Laterality

 Left

Reference

 Right

1.042(0.986 ~ 1.102)

0.147

Primary site

 Upper lobe

Reference

Reference

 Middle lobe

0.766(0.654 ~ 0.896)

 < 0.001

1.016(0.892 ~ 1.158)

 < 0.001

 Lower lobe

0.593(0.487 ~ 0.722)

 < 0.001

1.122(1.056 ~ 1.192)

0.807

 Others

0.802(0.683 ~ 0.942)

 < 0.001

1.156(0.983 ~ 1.358)

 < 0.001

Grade

 Unknown

Reference

Reference

 I

0.477(0.377 ~ 0.604)

 < 0.001

0.622(0.533 ~ 0.725)

 < 0.001

 II

0.269(0.215 ~ 0.336)

 < 0.001

1.142(1.001 ~ 1.303)

 < 0.001

 III

0.7(0.569 ~ 0.862)

 < 0.001

1.488(1.304 ~ 1.698)

 < 0.001

 IV

1.106(0.898 ~ 1.361)

 < 0.001

1.261(0.982 ~ 1.618)

 < 0.001

Stage

 IA

Reference

Reference

 IB

0.281(0.259 ~ 0.304)

 < 0.001

1.47(1.243 ~ 1.739)

 < 0.001

 IIA

0.539(0.498 ~ 0.584)

 < 0.001

1.977(1.641 ~ 2.382)

 < 0.001

 IIB

0.896(0.823 ~ 0.975)

 < 0.001

2.088(1.596 ~ 2.733)

 < 0.001

Surgery

 Sub-lobectomy

Reference

Reference

 Lobectomy

0.399(0.292 ~ 0.546)

 < 0.001

0.763(0.699 ~ 0.832)

 < 0.001

 Pneumonectomy

0.371(0.273 ~ 0.505)

 < 0.001

0.982(0.865 ~ 1.114)

 < 0.001

 Palliative

0.716(0.52 ~ 0.984)

 < 0.001

1.561(1.131 ~ 2.154)

0.775

Chemotherapy

 No/unknown

Reference

Reference

 Yes

0.568(0.534 ~ 0.605)

 < 0.001

0.858(0.795 ~ 0.925)

 < 0.001

Nodes

 0

Reference

Reference

 1 ~ 9

1.092(0.919 ~ 1.297)

 < 0.001

0.628(0.566 ~ 0.698)

 < 0.001

 10 ~ 19

0.817(0.698 ~ 0.956)

 < 0.001

0.533(0.475 ~ 0.599)

 < 0.001

 20 ~ 29

0.793(0.675 ~ 0.931)

 < 0.001

0.449(0.387 ~ 0.521)

 < 0.001

 ≥ 30

0.772(0.641 ~ 0.93)

 < 0.001

0.542(0.451 ~ 0.652)

 < 0.001

Positive

 No/unknown

Reference

Reference

 Yes

0.457(0.426 ~ 0.491)

 < 0.001

1.339(1.165 ~ 1.539)

 < 0.001

TumorSize

 ≤ 9 mm

Reference

Reference

 10–19 mm

0.262(0.217 ~ 0.317)

 < 0.001

1.289(1.058 ~ 1.572)

 < 0.001

 20–29 mm

0.392(0.364 ~ 0.421)

 < 0.001

1.662(1.363 ~ 2.027)

0.012

 ≥ 30 mm

0.57(0.533 ~ 0.61)

 < 0.001

2.207(1.797 ~ 2.712)

 < 0.001

Number

 1

Reference

 ≥ 2

0.93(0.864 ~ 1.001)

0.052