Table 1 Baseline characteristics of included patients

Age (yrs)

66.7 ± 12.4

64.2 ± 11.5

0.039

Gender, n(%)

0.365

 Male

81 (49.1)

110 (44.2)

 Female

84 (50.9)

138 (55.4)

BMI (kg/m²)

24.7 ± 3.98

24.9 ± 2.24

0.557

Smoking status, n(%)

0.350

 Current or ever smoking

44 (26.7)

56 (22.5)

 Never smoking

121 (73.3)

193 (77.5)

Alcohol drinking status, n(%)

0.205

 Current or ever drinking

47 (28.5)

57 (22.9)

 Never drinking

118 (71.5)

192 (77.1)

Histological type, n(%)

0.897

 Adenocarcinoma

134 (81.2)

204 (81.9)

 Special types of cancer

31 (18.8)

45 (18.1)

ASA, n(%)

0.605

 II

137 (83)

201 (80.7)

 III

28 (17)

48 (19.3)

Type of operation, n(%)

0.756

 Laparoscopy

147 (89.1)

218 (87.6)

 Laparotomy

18 (10.9)

31 (12.4)

Tumor location, n(%)

0.718

 Rectum

126 (76.4)

195 (78.3)

 Colon

39 (23.6)

54 (21.7)

Lymphatic invasion, n(%)

46 (27.9)

71 (28.5)

0.912

Perineural invasion, n(%)

70 (42.4)

108 (43.4)

0.919

Neoadjuvant therapy, n(%)

19 (11.5)

32 (12.9)

0.761

Adjuvant therapy, n(%)

105 (63.6)

165 (66.3)

0.599

Pre-surgery PNI

48.5 ± 6.32

48.8 ± 6.55

0.641

Post-surgery PNI

46.8 ± 6.14

45.5 ± 6.32

0.037

ΔPNI

-1.72 ± 3.52

-5.32 ± 8.76

 < 0.001