Table 4 Clinical characteristics of left-sided and right-sided CRC in the SEER database

Median age (min–max)

71 (13–108)

63 (11–106)

67 (11–108)

Gender

 Male

22.99

27.58

50.57

 Female

27.64

21.79

49.43

Race (%)

 White

40.65

38.82

79.47

 Black

6.52

4.99

11.51

 Asian

2.84

4.73

7.57

 Other

0.61

0.85

1.46

Stage at presentation (%)

 Stage 0

0.61

0.50

1.11

 Stage I

10.67

11.23

21.90

 Stage II

16.67

13.66

30.32

 Stage III

15.53

17.53

33.06

 Stage IV

7.14

6.46

13.60

Histologic subtype (%)

 Adenocarcinoma

43.49

46.04

89.54

 Mucinous adenocarcinoma

5.67

2.69

8.37

 Other

1.45

0.64

2.10

Histologic grade (%)

 Well differentiated

4.33

4.21

8.54

 Moderately differentiated

33.63

37.77

71.40

 Poorly differentiated

10.85

6.58

17.43

 Undifferentiated

1.81

0.82

2.63

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

 Yes

41.94

34.62

76.56

 No

8.57

14.60

23.17

 Missing data

0.11

0.16

0.27

Type of surgery (%)

 Local excision

0.06

0.39

0.45

 Partial colectomy

9.93

34.68

44.60

 Hemicolectomy

39.34

8.43

47.77

 Total colectomy

0.70

4.34

5.04

 Other colectomy

0.55

1.38

1.94

 No surgery

0.04

0.15

0.19

Chemotherapy (%)

 Yes

15.59

24.48

40.07

 No/unknown

35.03

24.90

59.93

Radiation therapy (%)

 Yes

0.53

12.26

12.79

 No/unknown

50.09

37.12

87.21