Table 2 Univariate and multivariate Cox analysis of overall survival and breast cancer-specific survival

Age

< 0.001

< 0.001

 18–29

Reference

Reference

Reference

Reference

 30–39

1.088 (0.550–2.154)

0.808

1.325 (0.668–2.628)

0.421

1.189 (0.578–2.446)

0.638

1.450 (0.702–2.993)

0.315

 40–49

0.779 (0.401–1.515)

0.462

1.074 (0.551–2.092)

0.834

0.758 (0.374–1.535)

0.442

1.118 (0.551–2.271)

0.757

 50–59

0.989 (0.511–1.914)

0.973

1.354 (0.698–2.626)

0.370

0.882 (0.437–1.778)

0.725

1.334 (0.660–2.699)

0.422

 60–69

1.191 (0.616–2.303)

0.604

1.677 (0.865–3.250)

0.126

0.879 (0.435–1.772)

0.718

1.429 (0.706–2.892)

0.321

 70–79

2.089 (1.080–4.041)

0.029

2.603 (1.341–5.053)

0.005

1.349 (0.667–2.726)

0.404

2.063 (1.016–4.190)

0.045

 ≥80

5.019 (2.594–9.712)

< 0.001

5.233 (2.685–10.200)

< 0.001

2.429 (1.197–4.929)

0.014

3.433 (1.673–7.043)

0.001

Race

< 0.001

< 0.001

 White

Reference

Reference

Reference

Reference

 Black

1.503 (1.333–1.694)

< 0.001

1.357 (1.200–1.535)

< 0.001

1.747 (1.517–2.012)

< 0.001

1.493 (1.291–1.726)

< 0.001

 Other

0.661 (0.551–0.792)

< 0.001

0.732 (0.611–0.879)

0.001

0.799 (0.649–0.983)

0.034

0.807 (0.655–0.995)

0.045

Marital status

< 0.001

< 0.001

 Married

Reference

Reference

Reference

Reference

 Unmarried

2.012 (1.846–2.192)

< 0.001

1.362 (1.244–1.490)

< 0.001

1.671 (1.505–1.855)

< 0.001

1.212 (1.086–1.353)

0.001

Grade

< 0.001

< 0.001

 I

Reference

Reference

Reference

Reference

 II

1.426 (1.238–1.644)

< 0.001

1.249 (1.082–1.442)

0.002

1.873 (1.519–2.311)

< 0.001

1.540 (1.247–1.902)

< 0.001

 III

2.742 (2.379–3.160)

< 0.001

2.204 (1.904–2.551)

< 0.001

5.043 (4.108–6.190)

< 0.001

3.557 (2.886–4.385)

< 0.001

 IV

2.647 (1.248–5.612)

0.011

2.009 (0.945–4.274)

0.070

5.221 (2.293–11.889)

< 0.001

3.483 (1.523–7.965)

0.003

T stage

< 0.001

< 0.001

 T1

Reference

Reference

Reference

Reference

 T2

2.232 (2.002–2.489)

< 0.001

1.941 (1.121–3.362)

0.018

2.735 (2.365–3.163)

< 0.001

2.249 (1.209–4.183)

0.010

 T3

3.315 (2.893–3.800)

< 0.001

1.737 (1.005–3.000)

0.048

4.910 (4.144–5.817)

< 0.001

2.479 (1.340–4.585)

0.004

 T4

6.625 (5.621–7.808)

< 0.001

2.790 (1.681–4.632)

< 0.001

9.521 (7.791–11.635)

< 0.001

3.471 (1.962–6.143)

< 0.001

N stage

< 0.001

< 0.001

 N1

Reference

Reference

Reference

Reference

 N2

1.894 (1.706–2.103)

< 0.001

0.980 (0.757–1.268)

0.875

2.409 (2.122–2.734)

< 0.001

1.007 (0.751–1.350)

0.963

 N3

3.234 (2.888–3.622)

< 0.001

1.029 (0.747–1.417)

0.862

4.570 (4.008–5.211)

< 0.001

1.124 (0.793–1.594)

0.511

M stage

< 0.001

< 0.001

 M0

Reference

Reference

Reference

Reference

 M1

5.668 (4.961–6.476)

< 0.001

1.779 (1.318–2.403)

< 0.001

8.160 (7.066–9.423)

< 0.001

2.191 (1.591–3.019)

< 0.001

Histology

0.223

0.233

 Infiltrating duct carcinoma

 Lobular carcinoma

 Other

Location

0.012

0.353

 Nipple

Reference

 Central portion of breast

0.864 (0.519–1.437)

0.573

 Upper-inner quadrant of breast

0.659 (0.396–1.095)

0.108

 Lower-inner quadrant of breast

0.712 (0.422–1.202)

0.204

 Upper-outer quadrant of breast

0.653 (0.398–1.071)

0.091

 Lower-outer quadrant of breast

0.705 (0.423–1.173)

0.178

 Axillary tail of breast

0.925 (0.467–1.831)

0.823

 Overlapping lesion of breast

0.728 (0.443–1.196)

0.210

Laterality

0.859

0.641

 Right: origin of primary

 Left: origin of primary

Tumor size, cm

< 0.001

< 0.001

 ≤1

Reference

Reference

Reference

Reference

 ≤2

1.139 (0.904–1.435)

0.271

1.069 (0.848–1.348)

0.573

1.218 (0.883–1.680)

0.229

1.112 (0.805–1.537)

0.518

 ≤3

2.017 (1.611–2.526)

< 0.001

0.789 (0.448–1.390)

0.412

2.302 (1.686–3.144)

< 0.001

0.697 (0.365–1.329)

0.273

 ≤4

3.097 (2.456–3.906)

< 0.001

1.020 (0.580–1.794)

0.945

4.322 (3.153–5.926)

< 0.001

1.068 (0.561–2.034)

0.840

 ≤5

3.552 (2.782–4.534)

< 0.001

1.167 (0.661–2.058)

0.595

5.242 (3.782–7.266)

< 0.001

1.234 (0.648–2.352)

0.523

 > 5

4.122 (3.283–5.176)

< 0.001

1.328 (0.765–2.306)

0.313

6.262 (4.595–8.534)

< 0.001

1.161 (0.621–2.171)

0.641

Positive regional nodes number

< 0.001

< 0.001

 1–3

Reference

Reference

Reference

Reference

 4–9

1.980 (1.789–2.192)

< 0.001

1.635 (1.270–2.104)

< 0.001

2.561 (2.265–2.896)

< 0.001

1.823 (1.367–2.430)

< 0.001

 ≥10

3.377 (3.010–3.788)

< 0.001

2.357 (1.698–3.270)

< 0.001

4.778 (4.179–5.463)

< 0.001

2.654 (1.852–3.802)

< 0.001

Bone metastasis

< 0.001

< 0.001

 No

Reference

Reference

Reference

Reference

 Yes

5.975 (5.130–6.959)

< 0.001

1.571 (1.159–2.129)

0.004

8.577 (7.289–10.093)

< 0.001

1.629 (1.179–2.251)

0.003

Brain metastasis

< 0.001

< 0.001

 No

Reference

Reference

Reference

Reference

 Yes

11.721 (6.479–21.204)

< 0.001

4.449 (2.381–8.313)

< 0.001

17.863 (9.865–32.342)

< 0.001

4.619 (2.440–8.745)

< 0.001

Liver metastasis

< 0.001

< 0.001

 No

Reference

Reference

Reference

Reference

 Yes

7.592 (5.630–10.238)

< 0.001

2.092 (1.494–2.929)

< 0.001

11.141 (8.191–15.155)

< 0.001

2.061 (1.457–2.916)

< 0.001

Lung metastasis

< 0.001

< 0.001

 No

Reference

Reference

Reference

Reference

 Yes

7.004 (5.303–9.249)

< 0.001

0.895 (0.644–1.243)

0.506

9.452 (7.020–12.7250

< 0.001

0.974 (0.686–1.382)

0.883

Surgery

< 0.001

< 0.001

 No

Reference

Reference

Reference

Reference

 Yes

0.220 (0.173–0.281)

< 0.001

0.401 (0.311–0.517)

< 0.001

0.169 (0.130–0.221)

< 0.001

0.288 (0.217–0.382)

< 0.001

Radiotherapy

< 0.001

< 0.001

 No/Unknown

Reference

Reference

Reference

Reference

 Yes

0.591 (0.543–0.643)

< 0.001

0.677 (0.619–0.741)

< 0.001

0.731 (0.658–0.812)

< 0.001

0.787 (0.704–0.881)

< 0.001

Chemotherapy

< 0.001

0.050

 No/Unknown

Reference

Reference

Reference

Reference

 Yes

0.577 (0.530–0.628)

< 0.001

0.792 (0.712–0.882)

< 0.001

0.897 (0.805–1.000)

0.051

0.937 (0.818–1.072)

0.340