Table 3 Multiple COX regression results of OS and Non-cancer-specific survival (NCCSS) in CRC patients with lung metastasis

 Age

< 0.001

  < 65

1

  ≥ 65

1.242

1.156–1.335

 AJCC T stage

< 0.001

  T0

1

  T1

1.119

0.358–3.502

0.847

  T2

0.941

0.293–3.019

0.918

  T3

0.922

0.295–2.884

0.889

  T4

1.186

0.379–3.710

0.770

  Tx

1.067

0.342–3.330

0.911

 AJCC N stage

0.012

  N0

1

  N1

1.038

0.950–1.134

0.410

  N2

1.175

1.046–1.319

0.007

  N3

1.135

1.012–1.274

0.031

 Osseous metastasis

< 0.001

  No

1

  Yes

1.601

1.429–1.793

< 0.001

  Unknown

1.249

0.892–1.750

0.195

 Brain metastasis

< 0.001

  No

1

  Yes

1.648

1.321–2.058

< 0.001

  Unknown

0.926

0.678–1.264

0.628

 Liver metastasis

< 0.001

  No

1

  Yes

1.670

1.532–1.821

< 0.001

  Unknown

1.136

0.759–1.699

< 0.001

 Site

< 0.001

  Right-sided colon

1

  Left-sided colon

0.765

0.696–0.840

< 0.001

  Rectum

0.679

0.618–0.745

< 0.001

  Rectosigmoid Junction

0.703

0.621–0.796

< 0.001

 Surgery

< 0.001

  Yes

1

  No/Unknown

1.519

1.414–1.632

 Grade

< 0.001

  Grade I

1

  Grade II

1.108

0.922–1.332

0.272

  Grade III

1.541

1.262–1.881

< 0.001

  Grade IV

1.539

1.156–2.049

0.003

  Unknown

1.171

0.968–1.418

0.104

 Age

< 0.001

  < 65

1

  ≥ 65

1.926

1.483–2.502

 AJCC T stage

< 0.001

  T0

1

  T1

0.136

0.358–3.502

0.006

  T2

0.182

0.293–3.019

0.027

  T3

0.110

0.295–2.884

0.002

  T4

0.115

0.379–3.710

0.003

  Tx

0.187

0.342–3.330

0.019

 Chemotherapy

< 0.001

  Yes

1

  No/Unknown

3.185

2.520–4.024

 Marital status

< 0.001

  Married

1

  Single

1.757

1.380–2.237

< 0.001

  Unknown

2.392

1.651–3.467

< 0.001