Table 2 Univariable and multivariable analyses for cancer-specific mortality in the SEER database

Sex

 Male

1 [reference]

1 [reference]

1 [reference]

 Female

0.80 (0.65–0.97)

0.025

0.79 (0.66–0.96)

0.019

0.77 (0.63–0.94)

0.011

Age (years)

 ≤ 65

1 [reference]

1 [reference]

1 [reference]

 > 65

1.79 (1.45–2.20)

< 0.001

1.88 (1.51–2.33)

< 0.001

1.88 (1.51–2.33)

< 0.001

Location

 Upper lobe

1 [reference]

1 [reference]

1 [reference]

 Lower lobe

1.29 (1.04–1.60)

0.019

1.23 (0.99–1.53)

0.062

1.19 (0.96–1.48)

0.113

 Other/unknown

1.23 (0.88–1.72)

0.230

1.27 (0.90–1.78)

0.174

1.16 (0.83–1.63)

0.390

Tumor size

 ≤ 3.0 cm

1 [reference]

1 [reference]

1 [reference]

 > 3.0 cm

1.30 (1.04–1.62)

0.022

1.36 (1.08–1.71)

0.010

1.34 (1.07–1.69)

0.012

Grade

 I-II

1 [reference]

1 [reference]

1 [reference]

 III

1.08 (0.69–1.69)

0.743

1.37 (0.86–2.16)

0.181

1.33 (0.84–2.11)

0.218

 IV

1.19 (0.75–1.87)

0.460

1.43 (0.90–2.26)

0.130

1.37 (0.87–2.17)

0.174

 Unknown

1.17 (0.74–1.85)

0.508

1.48 (0.92–2.36)

0.103

1.43 (0.90–2.28)

0.136

Surgery Approach

 Lobectomy/pneumonectomy

1 [reference]

1 [reference]

1 [reference]

 Sub-lobectomy

1.53 (1.22–1.92)

< 0.001

1.50 (1.18–1.90)

0.001

1.22 (0.97–1.55)

0.093

Chemotherapy

 No

1 [reference]

1 [reference]

1

 Yes

1.01 (0.81–1.25)

0.954

0.77 (0.60-1.00)

0.046

0.86 (0.67–1.11)

0.250

Radiotherapy

 No

1 [reference]

1 [reference]

1 [reference]

 Yes

1.26 (1.03–1.55)

0.024

1.01 (0.79–1.29)

0.957

0.93 (0.73–1.19)

0.578

 Unknown

0.79 (0.35–1.78)

0.566

0.58 (0.25–1.34)

0.202

0.55 (0.24–1.25)

0.152

pN classification

 pN0

1 [reference]

1 [reference]

 pN1

2.45 (1.93–3.11)

< 0.001

2.88 (2.24–3.72)

< 0.001

 pN2

2.64 (2.06–3.37)

< 0.001

2.75 (2.09–3.61)

< 0.001

New pN classification

 New pN#1

1 [reference]

1 [reference]

 New pN#2

2.01 (1.55–2.60)

< 0.001

1.94 (1.49–2.53)

< 0.001

 New pN#3

3.76 (2.96–4.76)

< 0.001

4.07 (3.14–5.28)

< 0.001

-2LogLikelihood value

4705.775

4677.544

AIC

4731.775

4705.544

BIC

4800.192

4771.961

 C-index (SE)

0.617 (0.013)

0.654 (0.014)