Table 1 Baseline characteristics for the study population

Age^a

71.1 [62.1–75.1]

71.6 [62.1–76]

70.6 [64–72.1]

Sex

 Female

29 (35.4%)

23 (35.9%)

6 (33.3%)

 Male

53 (64.6%)

41 (64.1%)

12 (66.7%)

ASA score

 ASA II

16 (19.5%)

11 (17.2%)

5 (27.8%)

 ASA III

65 (79.3%)

53 (82.8%)

12 (66.7%)

 ASA IV

1 (1.2%)

0 (0%)

1 (5.6%)

BMI

24.2 [22.1–26]

24.3 [22.5–26.1]

23.2 [21.9–26]

Serum CA 19–9 (U/ml)^a

88.4 [27–368]

96.7 [27.3–381.]

49.5 [13.5–339]

Platelet count^a (G/l)

232 [178–279]

235 [177–310]

225 [181–272]

Type of surgery

 PD

55 (67.1%)

45 (70.3%)

10 (55.6%)

 DP

18 (22%)

13 (20.3%)

5 (27.8%)

 TP

9 (11%)

6 (9.4%)

3 (16.7%)

RBC during surg. (units)^a

 Yes

9 (11%)

6 (9.4%)

3 (16.7%)

 No

73 (89%)

58 (90.6%)

15 (83.3%)

Additional venous resection

 Yes

25 (30.5%)

19 (29.7%)

6 (33.3%)

 No

57 (69.5%)

45 (70.3%)

12 (66.7%)

Tumor diameter max (cm)^a

3.3 [2.5–4.3]

3.2 [2.5–4.4]

3.3 [2.3–4.2]

T stage

 T1 + 2

6 (7.3%)

4 (6.2%)

2 (11.1%)

 T3

76 (92.7%)

60 (93.8%)

16(88.9%)

N stage

 N0

25 (30.5%)

20 (31.2%)

5 (27.8%)

 N1

57 (69.5%)

44 (68.8%)

13 (72.2%)

ELN^a

26 [19–35]

25 [19–34]

33 [27–39]

LNR^a

0.07 [0.0–0.16]

0.09 [0.0–0.17]

0.04 [0.0–0.08]

Grading

 G1

1 (1.2%)

1 (1.6%)

0 (0%)

 G2

23 (28%)

17 (26.6%)

6 (33.3%)

 G3

58 (70.7%)

46 (71.9%)

12 (66.7%)

Perineural invasion

 Pn0

11 (13.4%)

7 (10.9%)

4 (22.2%)

 Pn1

71 (86.6%)

57 (89.1%)

14 (77.8%)

Vascular invasion

 V0

68 (82.9%)

53 (82.8%)

15 (83.3%)

 V1

14 (17.1%)

11 (17.2%)

3 (16.7%)

Lymphovascular invasion

 L0

49 (59.8%)

36 (56.2%)

13 (72.2%)

 L1

33 (40.2%)

28 (43.8%)

5 (27.8%)

R status

 R0 wide

29 (35.4%)

24 (37.5%)

5 (27.8%)

 R0 narrow

35 (42.7%)

25 (39.1%)

10 (55.6%)

 R1

18 (22%)

15 (23.4%)

3 (16.7%)

Adjuvant therapy

 Yes

48 (58.5%)

36 (56.2%)

12 (66.7%)

 No

8 (9.8%)

8 (12.5%)

0 (0%)

 Unknown

26 (31.7%)

20 (31.2%)

6 (33.3%)