Table 1 Comparison of preoperative demographic data between the two groups (x² ± s)

Number of patients

36

128

Age (years)

62 ± 7

61 ± 8

0.335

0.966

Sex

 M

20

70

0.926^c

0.009

 F

16

58

BMI (kg/m² )

23.0 ± 1.7

23.4 ± 1.7

0.298

 − 1.043

Tumor position

 Lower sigmoid colon

15

60

0.579 ^c

0.307

 Upper rectum

21

68

Tumor differentiation

 High

6

26

0.856^c

0.311

 Moderate

27

90

 Low

3

12

Tumor diameter^a (cm)

4.2 ± 0.5

4.6 ± 0.6

0.000^b

 − 4.442

ASA classification

 I

8

20

0.632^c

0.916

 II

22

87

 III

6

21