Table 2 Univariate and multivariate analyses of factors for OS after PSM

Age, years

 < 65

Reference

Reference

 >  = 65

2.36

1.74

3.20

 < 0.001

2.21

1.58

3.10

 < 0.001

Race

 Black

Reference

Reference

 White

0.54

0.35

0.83

0.006

0.51

0.33

0.81

0.004

 Others or Unknown

0.73

0.44

1.22

0.233

0.83

0.49

1.40

0.478

Year of diagnosis

 2004–2008

Reference

Reference

 2009–2013

0.87

0.64

1.19

0.377

0.80

0.58

1.10

0.168

 2014–2017

0.73

0.51

1.05

0.087

0.69

0.48

0.99

0.047

Tumor size, mm

 <  = 40

Reference

Reference

 > 40, <  = 60

1.15

0.85

1.55

0.370

1.66

1.22

2.28

0.001

 > 60

1.32

0.92

1.88

0.130

1.47

1.01

2.15

0.045

Grade

 Well differentiated

Reference

Reference

 Moderately differentiated

1.26

0.82

1.94

0.293

1.21

0.78

1.88

0.392

 Poorly differentiated

1.93

1.23

3.02

0.004

1.66

1.04

2.65

0.033

 Undifferentiated; anaplastic

2.81

1.62

4.88

 < 0.001

2.28

1.27

4.10

0.006

 Unknown

2.72

1.68

4.43

 < 0.001

1.81

1.09

3.00

0.023

FIGO stage

 IB3/IIA2-IIB

Reference

Reference

 III

2.17

1.65

2.85

 < 0.001

0.80

0.40

1.60

0.531

 IVA

3.80

1.75

8.24

0.001

5.06

2.20

11.64

 < 0.001

T stage

 T1

Reference

Reference

 T2

1.59

1.17

2.15

0.003

1.60

1.17

2.21

0.004

 T3

2.91

1.98

4.28

 < 0.001

3.31

2.01

5.45

 < 0.001

 T4

3.68

1.68

8.04

0.001

—

—

—

—

N stage

 N0

Reference

Reference

 N1

1.88

1.45

2.44

 < 0.001

2.38

1.27

4.44

0.007

Chemotherapy

 No

Reference

—

 Yes

1.13

0.80

1.59

0.498

—

—

—

—

Local treatment

 Primary RT

Reference

Reference

 Surgery + PORT

0.64

0.48

0.86

0.003

0.60

0.44

0.81

0.001