Table 1 Baseline characteristics of unmatched 530 PDAC patients

Gender, n (%)

 Male

296 (55.8%)

259 (56.8%)

37 (50.0%)

0.334

 Female

234 (44.2%)

197 (43.2%)

37 (50.0%)

Age (year)

 Mean ± SD

60.5 ± 9.17

60.5 ± 9.13

60.2 ± 9.43

0.752

Symptom, n (%)

 without symptoms

111 (20.9%)

107 (23.5%)

4 (5.4%)

< 0.001

 with symptoms

419 (79.1%)

349 (76.5%)

70 (94.6%)

Body mass index (BMI)

 Mean ± SD

23.5 ± 3.35

23.5 ± 3.30

23.5 ± 3.62

0.886

ASA score, n (%)

 1

21 (4.0%)

21 (4.6%)

0 (0%)

0.148

 2

410 (77.4%)

352 (77.2%)

58 (78.4%)

 3

99 (18.7%)

83 (18.2%)

16 (21.6%)

Surgical method, n (%)

 Whipple

250 (47.2%)

193 (42.3%)

57 (77.0%)

< 0.001

 Distal pancreatectomy

273 (51.5%)

257 (56.4%)

16 (21.6%)

 Other

7 (1.3%)

6 (1.3%)

1 (1.4%)

Resection of spleen, n (%)

 No

281 (53.0%)

222 (48.7%)

59 (79.7%)

< 0.001

 Yes

249 (47.0%)

234 (51.3%)

15 (20.3%)

Site of tumor, n (%)

 Pancreatic head

264 (49.8%)

205 (45.0%)

59 (79.7%)

< 0.001

 Pancreatic body/tail

266 (50.2%)

251 (55.0%)

15 (20.3%)

Size of tumor (cm)

 Median [Min, Max]

3.50 [0.300, 13.0]

3.50 [0.300, 13.0]

3.50 [1.00, 6.80]

0.313

AJCC stage, n (%)

 I

198 (37.4%)

166 (36.4%)

32 (43.2%)

0.523

 II

270 (50.9%)

237 (52.0%)

33 (44.6%)

 III

58 (10.9%)

49 (10.7%)

9 (12.2%)

 IV

4 (0.8%)

4 (0.9%)

0 (0%)

pT, n (%)

 1

58 (10.9%)

50 (11.0%)

8 (10.8%)

0.562

 2

301 (56.8%)

254 (55.7%)

47 (63.5%)

 3

169 (31.9%)

150 (32.9%)

19 (25.7%)

 4

2 (0.4%)

2 (0.4%)

0 (0%)

pN, n (%)

 0

290 (54.7%)

250 (54.8%)

40 (54.1%)

0.914

 1

183 (34.5%)

158 (34.6%)

25 (33.8%)

 2

57 (10.8%)

48 (10.5%)

9 (12.2%)

Differentiation, n (%)

 Poor

73 (13.8%)

62 (13.6%)

11 (14.9%)

0.521

 Moderate

385 (72.6%)

332 (72.8%)

53 (71.6%)

 Well

72 (13.6%)

66 (13.6%)

10 (13.5%)

Surgical margin, n (%)

 R0

512 (96.6%)

440 (96.5%)

72 (97.3%)

0.993

 R1

18 (3.4%)

16 (3.5%)

2 (2.7%)

Lymphovascular invasion, n (%)

 No

376 (70.9%)

325 (71.3%)

51 (68.9%)

0.783

 Yes

154 (29.1%)

131 (28.7%)

23 (31.1%)

Neural invasion, n (%)

 No

154 (29.1%)

132 (28.9%)

22 (29.7%)

1

 Yes

376 (70.9%)

324 (71.1%)

52 (70.3%)

Capsule invasion, n (%)

 No

121 (22.8%)

99 (21.7%)

22 (29.7%)

0.169

 Yes

409 (77.2%)

357 (78.3%)

52 (70.3%)

Bile duct invasion, n (%)

 No

365 (68.9%)

331 (72.6%)

34 (45.9%)

< 0.001

 Yes

165 (31.1%)

125 (27.4%)

40 (54.1%)

Duodenal invasion, n (%)

 No

402 (75.8%)

359 (78.7%)

43 (58.1%)

< 0.001

 Yes

128 (24.2%)

97 (21.3%)

31 (41.9%)

Spleen invasion, n (%)

 No

482 (90.9%)

414 (90.8%)

68 (91.9%)

0.93

 Yes

48 (9.1%)

42 (9.2%)

6 (8.1%)

Preoperative CEA (ug/L)

 Median [Min, Max]

3.26 [0.340, 305]

3.28 [0.340, 305]

3.08 [0.680, 186]

0.366

Preoperative CA199 (ug/L)

 Median [Min, Max]

150 [0.600, 55400]

150 [0.600, 55400]

150 [0.600, 2480]

0.877

Preoperative CA242 (ug/L)

 Median [Min, Max]

31.3 [0.00500, 6280]

31.9 [0.0100, 6280]

26.1 [0.00500, 999]

0.094

PNI

 Median [Min, Max]

50.1 [7.35, 91.5]

50.9 [13.9, 91.5]

44.5 [7.35, 50.6]

< 0.001

SII

 Median [Min, Max]

493 [53.1, 7890]

447 [53.1, 3780]

1120 [835, 7890]

< 0.001

Neoadjuvant therapy, n (%)

 No

515 (97.2%)

442 (96.9%)

73 (98.6%)

0.653

 Yes

15 (2.8%)

14 (3.1%)

1 (1.4%)

Adjuvant therapy, n (%)

 No

253 (47.7%)

216 (47.4%)

37 (50.0%)

0.768

 Yes

277 (52.3%)

240 (52.6%)

37 (50.0%)

Postoperative radiotherapy, n (%)

 No

514 (97.0%)

440 (96.5%)

74 (100%)

0.204

 Yes

16 (3.0%)

16 (3.5%)

0 (0%)

Interventional therapy, n (%)

 No

519 (97.9%)

448 (98.2%)

71 (95.9%)

0.397

 Yes

11 (2.1%)

8 (1.8%)

3 (4.1%)