| Early period 1995 ~ 2012 (n = 316) | Late period 2013 ~ 2018 (n = 316) | p-value |  | ||||
---|---|---|---|---|---|---|---|---|
Clinical characteristics | Â | Â | Â | Â | ||||
 *Age | 65.8 ± 7.9 | 66.0 ± 8.2 | 0.759 |  | ||||
 *Sex |  |  | 0.802 |  | ||||
  Male | 204 (64.6) | 208 (65.8) |  |  | ||||
  Female | 112 (35.4) | 108 (34.2) |  |  | ||||
 *BMI (kg/m2) | 23.1 ± 3.0 | 23.3 ± 2.9 | 0.602 |  | ||||
 DM |  |  | 0.447 |  | ||||
  No | 249 (78.8) | 240 (75.9) |  |  | ||||
  Yes | 67 (21.2) | 76 (24.1) |  |  | ||||
 *ASA score |  |  | 0.627 |  | ||||
  1 | 51 (16.1) | 42 (13.3) |  |  | ||||
  2 | 233 (73.7) | 240 (75.9) |  |  | ||||
  3 | 32 (10.1) | 34 (10.8) |  |  | ||||
  4 | 0 (0.0) | 0 (0.0) |  |  | ||||
  Unknown | 0 (0.0) | 0 (0.0) |  |  | ||||
 Preoperative total bilirubin (mg/dL) | 9.6 ± 9.2 | 7.4 ± 7.7 | < 0.001 |  | ||||
 Preoperative biliary drainage |  |  | 0.041 |  | ||||
  No | 42 (13.3) | 62 (19.6) |  |  | ||||
  Yes | 274 (86.7) | 254 (80.4) |  |  | ||||
 Preoperative CA19-9 |  |  | 0.001 |  | ||||
\(\le\)37 U/mL | 122 (38.6) | 163 (51.6) | Â | Â | ||||
\(>\) 37 U/mL | 188 (59.5) | 141 (44.6) | Â | Â | ||||
  Unknown | 6 (1.9) | 12 (3.8) |  |  | ||||
Operative characteristics | Â | Â | Â | Â | ||||
 Operation type |  |  | 0.010 |  | ||||
  PPPD | 193 (61.1) | 228 (72.2) |  |  | ||||
  PRPD | 103 (32.6) | 68 (21.5) |  |  | ||||
  HPD | 16 (5.1) | 18 (5.7) |  |  | ||||
  TP | 4 (1.3) | 2 (0.6) |  |  | ||||
 Vascular resection |  |  | 0.475 |  | ||||
  No | 302 (95.6) | 297 (94.0) |  |  | ||||
  Yes | 14 (4.4) | 19 (6.0) |  |  | ||||
 Combined operation |  |  | 0.624 |  | ||||
  No | 309 (97.8) | 306 (96.8) |  |  | ||||
  Yes | 7 (2.2) | 10 (3.2) |  |  | ||||
 Operation duration (minutes) | 335.4 ± 66.6 | 322.0 ± 65.4 | 0.011 |  | ||||
 EBL (mL) | 675.5 ± 721.5 | 393.5 ± 275.0 | < 0.001 |  | ||||
 Intraoperative transfusion |  |  | < 0.001 |  | ||||
  No | 238 (75.3) | 294 (93.0) |  |  | ||||
  Yes | 78 (24.7) | 22 (7.0) |  |  | ||||
Pathological characteristics | Â | Â | Â | Â | ||||
 Tumor size | 2.9 ± 1.5 | 2.8 ± 1.3 | 0.131 |  | ||||
 T stage (AJCC 7th) |  |  | 0.042 |  | ||||
 |  | Tis | 1 (0.3) | Tis | 1 (0.3) |  |  | |
 |  | T1 | 25 (7.9) | T1 | 46 (14.6) |  |  | |
 |  | T2 | 83 (26.3) | T2 | 69 (21.8) |  |  | |
 |  | T3 | 206 (65.2) | T3 | 200 (63.3) |  |  | |
 |  | T4 | 1 (0.3) | T4 | 0 (0.0) |  |  | |
 Differentiation |  |  | < 0.001 |  | ||||
  Well | 47 (14.9) | 30 (9.5) |  |  | ||||
  Moderately | 164 (51.9) | 190 (60.1) |  |  | ||||
  Poorly | 82 (25.9) | 89 (28.2) |  |  | ||||
  Undifferentiated | 2 (0.6) | 5 (1.6) |  |  | ||||
  Unknown | 21 (6.6) | 2 (0.6) |  |  | ||||
 N stage (AJCC 8th) |  |  | 0.927 |  | ||||
  N0 | 206 (65.2) | 210 (66.5) |  |  | ||||
  N1 | 83 (26.3) | 81 (25.6) |  |  | ||||
  N2 | 27 (8.5) | 25 (7.9) |  |  | ||||
 Harvested LN | 21.4 ± 10.7 | 19.3 ± 8.9 | 0.009 |  | ||||
 Metastatic LN | 1.1 ± 2.3 | 0.9 ± 2.0 | 0.358 |  | ||||
 M stage |  |  | - |  | ||||
  M0 | 316 (100.0) | 316 (100.0) |  |  | ||||
  M1 | 0 (0.0) | 0 (0.0) |  |  | ||||
 Resection margin |  |  | 0.435 |  | ||||
  R0 | 294 (93.0) | 287 (90.8) |  |  | ||||
  R1 | 21 (6.6) | 26 (8.2) |  |  | ||||
  R2 | 1 (0.3) | 3 (0.9) |  |  | ||||
 Perineural invasion |  |  | < 0.001 |  | ||||
  No | 42 (13.3) | 67 (21.2) |  |  | ||||
  Yes | 177 (56.0) | 246 (77.8) |  |  | ||||
  Unknown | 97 (30.7) | 3 (0.9) |  |  | ||||
 Lymphovascular invasion |  |  | < 0.001 |  | ||||
  No | 27 (8.5) | 179 (56.6) |  |  | ||||
  Yes | 51 (16.1) | 134 (42.4) |  |  | ||||
  Unknown | 238 (75.3) | 3 (0.9) |  |  | ||||
Postoperative progression | Â | Â | Â | Â | ||||
 Postoperative hospitalization (days) | 19.8 ± 12.1 | 14.0 ± 7.5 | < 0.001 |  | ||||
 POPF |  |  | 0.167 |  | ||||
  No (biochemical leak) | 270 (85.4) | 281 (88.9) |  |  | ||||
  Grade B | 37 (11.7) | 32 (10.1) |  |  | ||||
  Grade C | 9 (2.8) | 3 (0.9) |  |  | ||||
 Clavien-Dindo classification |  |  | < 0.001 |  | ||||
  No complication | 160 (50.6) | 166 (52.5) |  |  | ||||
  I | 32 (10.1) | 2 (0.6) |  |  | ||||
  II | 46 (14.6) | 63 (19.9) |  |  | ||||
  IIIa | 51 (16.1) | 60 (19.0) |  |  | ||||
  IIIb | 12 (3.8) | 8 (2.5) |  |  | ||||
  IVa | 10 (3.2) | 13 (4.1) |  |  | ||||
  IVb | 0 (0.0) | 1 (0.3) |  |  | ||||
  V | 5 (1.6) | 3 (0.9) |  |  | ||||
 In-hospital mortality (%) | 4 (1.3) | 2 (0.6) | 0.412 |  | ||||
 30-day mortality (%) | 4 (1.3) | 3 (0.9) | 0.704 |  | ||||
 90-day mortality (%) | 8 (2.5) | 6 (1.9) | 0.589 |  | ||||
 Adjuvant treatment |  |  | < 0.001 |  | ||||
  No | 274 (86.7) | 211 (66.8) |  |  | ||||
  Yes | 42 (13.3) | 105 (33.2) |  |  |