Table 3 Multivariate Cox Regression for the whole cohort, the Right-sided cohort and the Left-sided cohort

Age at diagnosis

< 0.001

 < 40

1.000

1.000

1.000

 40–49

1.074 (0.962–1.199)

0.201

1.019 (0.875–1.187)

1.146 (0.977–1.343)

 50–59

1.144 (1.035–1.264)

.0.008

1.162 (1.014–1.333)

1.107 (0.956–1.281)

 60–69

1.466 (1.330–1.616)

< 0.001

1.422 (1.245–1.624)

1.462 (1.266–1.688)

 > 70

2.516 (2.287–2.769)

< 0.001

2.265 (1.987–2.581)

2.878 (2.500–3.312)

 Female vs. Male

0.804 (0.784–0.825)

< 0.001

0.796 (0.762–0.833)

Race

< 0.001

 Black

1.000

1.000

1.000

 White

0.866 (0.834–0.898)

< 0.001

0.907 (0.866–0.950)

0.797 (0.749–0.848)

 Hispanic/Latino

0.848 (0.718–1.001)

0.051

0.856 (0.696–1.052)

0.825 (0.625–1.090)

 Asian or Pacific Islander and others

0.687 (0.647–0.729)

< 0.001

0.699 (0.646–0.757)

0.663 (0.606–0.726)

 Unknown

0.471 (0.339–0.654)

< 0.001

0.482 (0.317–0.734)

0.462 (0.273–0.783)

 Yes vs. No

0.920 (0.881–0.962)

< 0.001

0.906 (0.857–0.958)

T stage

< 0.001

 T0-T2 (0, 2, 3)

1.000

1.00

1.000

 T3-T4 (4, 5)

1.703 (1.629–1.780)

< 0.001

1.540 (1.458–1.627)

1.984 (1.841–2.138)

 TX (6)

1.366 (0.933–1.999)

0.109

1.155 (0.693–1.926)

1.756 (0.991–3.112)

 N2 vs. N1

1.139 (1.097–1.181)

< 0.001

1.157 (1.105–1.211)

1.063 (1.005–1.124)

 Yes vs. No

0.499 (0.486–0.513)

< 0.001

0.501 (0.485–0.517)

0.491 (0.469–0.513)

Radiotherapy

 No

1.000

1.000

1.000

 Yes

1.286 (1.017–1.626)

0.036

1.402 (1.031–1.906)

1.253 (0.865–1.816)

 Unknown

0.866 (0.696–1.077)

0.196

0.851 (0.644–1.123)

0.886 (0.623–1.262)

Marital status

< 0.001

 Single, separated, divorced,

1.000

1.000

1.000

 Married (including common law)

0.785 (0.761–0.811)

< 0.001

0.844 (0.811–0.878)

0.733 (0.695–0.773)

 Windowed

1.078 (1.039–1.120)

< 0.001

1.051 (1.005–1.099)

1.029 (0.963–1.099)

 Unknown

0.875 (0.818–0.936)

< 0.001

0.904 (0.834–0.981)

0.812 (0.720–0.916)

Pathology grade

< 0.001

 Well-differentiated

1.000

1.000

1.000

 Moderately differentiated

1.086 (1.025–1.151)

0.005

1.145 (1.063–1.233)

1.003 (0.915–1.101)

 Poorly differentiated

1.340 (1.262–1.424)

< 0.001

1.378 (1.276–1.487)

1.282 (1.160–1.417)

 Undifferentiated

1.636 (1.507–1.777)

< 0.001

1.658 (1.502–1.830)

1.639 (1.393–1.928)

 Unknown

1.228 (1.115–1.352)

< 0.001

1.275 (1.133–1.435)

1.157 (0.979–1.368)

 Left-sided vs. Right-sided

0.847 (0.824–0.870)

< 0.001

Lymph nodes ratio

< 0.001

 < 0.07

1.000

1.000

1.000

 0.07–0.25

1.277 (1.229–1.325)

< 0.001

1.294 (1.236–1.354)

1.245 (1.167–1.328)

 0.25–0.50

1.602 (1.523–1.685)

< 0.001

1.663 (1.563–1.770)

1.514 (1.402–1.636)

 0.50–1.0

2.494 (2.357–2.640)

< 0.001

2.671 (2.491–2.863)

2.282 (2.100–2.480)

  ≥ 12 vs. < 12

0.747 (0.728–0.766)

< 0.001

0.706 (0.683–0.730)

0.780 (0.747–0.815)

 ≥ 12 vs. < 12

0.938 (0.909–0.967)

< 0.001

0.902 (0.886–0.957)

0.968 (0.919–1.020)

^bTotal number of lymph nodes (without Lymph nodes ratio)

1.000 (0.998–1.001)

0.694

0.981 (0.980–0.983)

0.985 (0.982–0.987)

Total number of lymph nodes (with Lymph nodes ratio)

1.004 (1.003–1.006)

< 0.001

0.994 (0.992–0.997)

0.996 (0.993–1.000)

  ≥ 11 vs. < 11

0.704 (0.669–0.740)

  ≥ 11 vs. < 11

0.868 (0.813–0.927)