Table 2 Univariate and multivariate regression analyses for OS

Age

  < 45

Ref

Ref

 45–64

0.978 (0.792–1.210)

0.844

1.124(0.906–1.394)

0.287

 65–84

1.541(1.247–1.903)

 < 0.001*

1.767(1.416–2.205)

 < 0.001*

  >  = 85

2.975(2.256–3.925)

 < 0.001*

2.998(2.193–4.099)

 < 0.001*

Sex

 Female

Ref

 Male

1.007(0.898–1.129)

0.906

Race

 White

Ref

Ref

 Black

1.392(1.153–1.681)

 < 0.001*

1.188(0.980–1.440)

0.079

 Asian or Pacific Islander

0.978(0.814–1.174)

0.810

1.008(0.837–1.212)

0.937

 American Indian/Alaska Native

0.552(0.229–1.330)

0.185

0.510(0.210–1.240)

0.138

Marital

 Single

Ref

Ref

 Married

0.712(0.615–0.824)

 < 0.001*

0.741(0.637–0.862)

 < 0.001*

 Divorced or Separated

1.111(0.908–1.357)

0.309

1.138(0.925–1.398)

0.220

 Widowed

1.370(1.137–1.652)

 < 0.001*

0.854(0.694–1.051)

0.136

 Unmarried or Domestic Partner

1.099(0.454–2.664)

0.834

1.592(0.652–3.883)

0.307

Radiation

 No

Ref

Ref

 Yes

0.739(0.641–0.851)

 < 0.001*

1.028(0.882–1.199)

0.721

Chemotherapy

 No

Ref

Ref

 Yes

0.498(0.443–0.560)

 < 0.001*

0.468(0.408–0.537)

 < 0.001*

Summary_stage

 Regional

Ref

Ref

 Distant

3.356(2.979–3.781)

 < 0.001*

1.122(0.673–1.871)

0.689

AJCC_Stage

 IIIA

Ref

Ref

 IIIB

2.116(1.582–2.831)

 < 0.001*

1.007(0.596–1.703)

0.979

 IIIC

3.112(2.289–4.229)

 < 0.001*

1.080(0.606–1.912)

0.793

 IVA

6.139(4.529–8.320)

 < 0.001*

2.816(1.322–5.996)

0.007*

 IVB

10.779(7.854–14.792)

 < 0.001*

4.024(1.888–8.576)

 < 0.001*

T

 T1

Ref

Ref

 T2

1.012(0.532–1.925)

0.971

0.971(0.507–1.861)

0.929

 T3

2.440(1.346–4.424)

0.003*

1.830(0.871–3.847)

0.111

 T4a

4.553(2.487–8.334)

 < 0.001*

2.832(1.333–6.017)

0.007*

 T4b

5.213(2.806–9.683)

 < 0.001*

2.393(1.100–5.205)

0.028*

N

 N1a

Ref

Ref

 N1b

1.272(1.086–1.492)

0.003*

1.229(1.046–1.443)

0.012*

 N1c

2.212(0.709–6.903)

0.171

4.400(1.329–14.564)

0.015*

 N2a

1.368(1.153–1.624)

 < 0.001*

2.021(0.579–7.050)

0.270

 N2b

2.140(1.820–2.516)

 < 0.001*

2.563(0.733–8.964)

0.141

Tumor_size

  ≤ 3.7 cm

Ref

Ref

 3.8–5.6 cm

1.268(1.094–1.470)

0.002*

1.008(0.864–1.175)

0.919

  ≥ 5.7 cm

1.711(1.461–2.003)

 < 0.001*

1.194(1.007–1.416)

0.040*

Regional_nodes_examined

 1–12

Ref

Ref

 13–16

0.703(0.599–0.825)

 < 0.001*

0.742(0.630–0.874)

 < 0.001*

  ≥ 17

0.652(0.568–0.748)

 < 0.001*

0.590(0.509–0.685)

 < 0.001*

Regional_nodes_positive

 1–3

Ref

Ref

 4–8

2.061(1.131–1.469)

 < 0.001*

0.620(0.180–2.140)

0.450

  ≥ 9

2.061(1.765–2.407)

 < 0.001*

0.844(0.243–2.930)

0.789