Table 1 Clinical characteristics of CRC in different sites in the SEER database

Median age (min–max)

71 (15–105)

71 (15–108)

70 (13–102)

65 (16-101)

64 (11–106)

61 (14–103)

67 (11–108)

Gender (%)

 Male

9.93

8.81

4.25

3.01

13.81

10.76

50.57

 Female

12.62

10.48

4.54

2.62

11.95

7.22

49.43

Race (%)

 White

18.29

15.38

6.97

4.11

20.04

14.67

79.46

 Black

2.92

2.47

1.13

0.89

2.67

1.43

11.51

 Asian

1.09

1.19

0.56

0.55

2.61

1.57

7.57

 Other

0.25

0.25

0.13

0.08

0.45

0.31

1.46

Stage at presentation (%)

 Stage 0

0.28

0.25

0.08

0.06

0.29

0.15

1.11

 Stage I

4.69

4.25

1.72

1.03

6.02

4.18

21.90

 Stage II

6.73

6.69

3.25

1.84

7.11

4.71

30.32

 Stage III

7.23

5.77

2.53

1.87

8.39

7.27

33.06

 Stage IV

3.61

2.33

1.20

0.83

3.95

1.67

13.60

Histologic subtype (%)

 Adenocarcinoma

19.23

16.54

7.73

5.13

24.21

16.70

89.54

 Mucinous adenocarcinoma

2.59

2.20

0.88

0.42

1.30

0.97

8.37

 Other

0.73

0.55

0.18

0.08

0.25

0.31

2.10

Histologic grade (%)

 Well differentiated

1.92

1.66

0.74

0.50

2.34

1.38

8.54

 Moderately differentiated

14.89

12.73

6.01

4.17

19.75

13.85

71.40

 Poorly differentiated

4.88

4.20

1.77

0.85

3.25

2.47

17.43

 Undifferentiated

0.85

0.69

0.27

0.12

0.43

0.27

2.63

Adequate lymph node examination (more than 12 nodes) (%)

 Yes

18.68

16.59

6.67

4.20

18.47

11.95

76.56

 No

3.81

2.66

2.10

1.43

7.23

5.93

23.17

 Missing data

0.06

0.04

0.02

0.01

0.06

0.09

0.27

Type of surgery (%)

 Local excision

0.02

0.03

0.01

0.02

0.11

0.26

0.45

 Partial colectomy

3.59

2.79

3.54

1.91

20.36

12.41

44.60

 Hemicolectomy

18.39

16.05

4.90

3.48

4.24

0.72

47.77

 Total colectomy

0.29

0.22

0.19

0.15

0.51

3.69

5.04

 Other colectomy

0.24

0.18

0.14

0.08

0.52

0.79

1.94

 No surgery

0.02

0.02

0.01

0.01

0.03

0.12

0.19

Chemotherapy (%)

 Yes

7.33

5.52

2.74

2.14

9.93

12.41

40.07

 No/unknown

15.21

13.77

6.05

3.49

15.83

5.57

59.93

Radiation therapy (%)

 Yes

0.32

0.15

0.06

0.07

0.81

11.38

12.79

 No/unknown

22.23

19.14

8.73

5.56

24.95

6.60

87.21