Table 1 Baseline characteristics
Variables | Total | Adjuvant chemotherapy cycles | Â | ||||
|---|---|---|---|---|---|---|---|
Not received (A) | Received (cycles) | P | |||||
7–8 or 10–12 cycles (B) | 4–6 or 6–9 cycles (C) | ≤3 or 5 cycles (D) | Total | ||||
n | 428 | 86 (20.1) | 175 (40.9) | 107 (25.0) | 60 (14.0) | 342 (79.9) | Â |
Age (years) |  |  |  |  |  |  | < 0.001 |
 Median | 60 | 66 | 57 | 60 | 62 | 59 |  |
 Range | 23–79 | 38–79 | 25–78 | 23–78 | 41–79 | 23–79 |  |
Sex | Â | Â | Â | Â | Â | Â | 0.458 |
 Female | 124 (29.0) | 26 (30.2) | 49 (28.0) | 27 (25.2) | 22 (36.7) | 98 (28.7) |  |
 Male | 304 (71.0) | 60 (69.8) | 126 (72.0) | 80 (74.8) | 38 (63.3) | 244 (71.3) |  |
BMI | Â | Â | Â | Â | Â | Â | 0.046 |
 Median | 23.4 | 22.7 | 23.9 | 22.6 | 23.8 | 23.5 |  |
 Range | 14.8–32.0 | 15.9–31.2 | 16.5–32.0 | 14.8–31.1 | 17.1–29.4 | 14.8–32.0 |  |
Surgical approach | Â | Â | Â | Â | Â | Â | 0.409 |
 Traditional open | 128 (29.9) | 22 (25.6) | 49 (28.0) | 37 (34.6) | 20 (33.3) | 106 (31.0) |  |
 Laparoscopic-assisted | 286 (66.8) | 62 (72.1) | 121 (69.1) | 67 (62.6) | 36 (60.0) | 224 (65.5) |  |
 Conversion to open | 14 (3.3) | 2 (2.3) | 5 (2.9) | 3 (2.8) | 4 (6.7) | 12 (3.5) |  |
Intraoperative blood loss | Â | Â | Â | Â | Â | Â | 0.323 |
  ≤ 100 ml | 351 (82.0) | 71 (82.6) | 137 (78.3) | 93 (86.9) | 50 (83.3) | 280 (81.9) |  |
 >100 ml | 77 (18.0) | 15 (17.4) | 38 (21.7) | 14 (13.1) | 10 (16.7) | 62 (18.1) |  |
Postoperative complications | Â | Â | Â | Â | Â | Â | 0.001 |
 Negative | 376 (87.9) | 65 (75.6) | 162 (92.6) | 96 (89.7) | 53 (88.3) | 311 (90.9) |  |
 Positive | 52 (12.1) | 21 (24.4) | 13 (7.4) | 11 (10.3) | 7 (11.7) | 31 (9.1) |  |
Tumor length/diameter (cm) | Â | Â | Â | Â | Â | Â | 0.010 |
 Median | 4.2 | 4.2 | 4.0 | 4.0 | 5.0 | 4.2 |  |
 Range | 0.3–19.0 | 1.5–14.3 | 0.3–19.0 | 1.5–14.0 | 2.0–13.0 | 0.3–19.0 |  |
Histological type | Â | Â | Â | Â | Â | Â | 0.511 |
 High differentiation adenocarcinoma | 3 (0.7) | 1 (1.2) | 1 (0.6) | 0 (0.0) | 1 (1.7) | 2 (0.6) |  |
 Median differentiation adenocarcinoma | 84 (19.6) | 22 (25.6) | 31 (17.7) | 21 (19.6) | 10 (16.7) | 62 (18.1) |  |
 Low differentiation adenocarcinoma | 173 (40.4) | 26 (30.2) | 78 (44.6) | 44 (41.1) | 25 (41.7) | 147 (43.0) |  |
 Median-Low differentiation adenocarcinoma | 132(30.8) | 30 (34.9) | 47 (26.9) | 35 (32.7) | 20 (33.3) | 102 (29.8) |  |
 Mucinous adenocarcinoma | 14 (3.3) | 4 (4.7) | 5 (2.9) | 3 (2.8) | 2 (3.3) | 10 (2.9) |  |
 Signet-ring cell carcinoma | 22 (5.1) | 3 (3.5) | 13 (7.4) | 4 (3.7) | 2 (3.3) | 19 (5.6) |  |
Vascular tumor embolus | Â | Â | Â | Â | Â | Â | 0.080 |
 Negative | 183 (42.8) | 46 (53.5) | 75 (42.9) | 42 (39.3) | 20 (33.3) | 137 (40.1) |  |
 Positive | 245 (57.2) | 40 (46.5) | 100 (57.1) | 65 (60.7) | 40 (66.7) | 205 (59.9) |  |
Depth of Invasion (T) | Â | Â | Â | Â | Â | Â | 0.661 |
 T1 | 4 (0.9) | 0 (0.0) | 2 (1.1) | 1 (0.9) | 1 (1.7) | 4 (0.9) |  |
 T2 | 46 (10.7) | 6 (7.0) | 19 (10.9) | 15 (14.0) | 6 (10.0) | 40 (11.7) |  |
 T3 | 177 (41.4) | 40 (46.5) | 74 (42.3) | 41 (38.3) | 22 (36.7) | 137 (40.1) |  |
 T4a | 194 (45.3) | 38 (44.2) | 78 (44.6) | 49 (45.8) | 29 (48.3) | 156 (45.6) |  |
 T4b | 7 (1.6) | 2 (2.3) | 2 (1.1) | 1 (0.9) | 2 (3.3) | 5 (1.5) |  |
Lymph node metastasis (N) | Â | Â | Â | Â | Â | Â | 0.092 |
 N0 | 91 (21.3) | 26 (30.2) | 38 (21.7) | 18 (16.8) | 9 (15.0) | 65 (19.0) |  |
 N1 | 108 (25.2) | 17 (19.8) | 43 (24.6) | 33 (30.8) | 15 (25.0) | 91 (26.6) |  |
 N2 | 105 (24.5) | 26 (30.2) | 38 (21.7) | 28 (26.2) | 13 (21.7) | 79 (23.1) |  |
 N3a | 90 (21.0) | 11 (12.8) | 39 (22.3) | 23 (21.5) | 17 (28.3) | 79 (23.1) |  |
 N3b | 34 (7.9) | 6 (7.0) | 17 (9.7) | 5 (4.7) | 6 (10.0) | 28 (8.2) |  |
TNM | Â | Â | Â | Â | Â | Â | 0.585 |
 II | 166 (38.8) | 37 (43.0) | 68 (38.9) | 42 (39.3) | 19 (31.7) | 129 (37.7) |  |
  IIA | 91 (21.3) | 20 (23.3) | 38 (21.7) | 23 (21.5) | 10 (16.7) |  |  |
  IIB | 75 (17.5) | 17 (19.8) | 30 (17.1) | 19 (17.8) | 9 (15.0) |  |  |
 III | 262 (61.2) | 49 (57.0) | 107 (61.1) | 65 (60.7) | 41 (68.3) | 213 (62.3) |  |
  IIIA | 139 (32.5) | 30 (34.9) | 54 (30.9) | 36 (33.6) | 19 (31.7) |  |  |
  IIIB | 89 (20.8) | 13 (15.1) | 36 (20.6) | 24 (22.4) | 16 (26.7) |  |  |
  IIIC | 34 (7.9) | 6 (7.0) | 17 (9.7) | 5 (4.7) | 6 (10.0) |  |  |
Serum CEA level | Â | Â | Â | Â | Â | Â | 0.184 |
 ≤ 5 ng/ml | 340 (79.4) | 65 (75.6) | 148 (84.6) | 82 (76.6) | 45 (75.0) | 275 (80.4) |  |
 >5 ng/ml | 88 (20.6) | 21 (24.4) | 27 (15.4) | 25 (23.4) | 15 (25.0) | 67 (19.6) |  |
Serum CA199 level | Â | Â | Â | Â | Â | Â | 0.272 |
 ≤ 37 U/ml | 371 (86.7) | 71 (82.6) | 156 (89.1) | 95 (88.8) | 49 (81.7) | 300 (87.7) |  |
 >37 U/ml | 57 (13.3) | 15 (17.4) | 19 (10.9) | 12 (11.2) | 11 (18.3) | 42 (12.3) |  |
Recurrence | Â | Â | Â | Â | Â | Â | 0.008 |
 Negative | 262 (61.2) | 43 (50.0) | 119 (68.0) | 70 (65.4) | 30 (50.0) | 219 (64.0) |  |
 Positive | 166 (38.8) | 43 (50.0) | 56 (32.0) | 37 (34.6) | 30 (50.0) | 123 (36.0) |  |
Survival |  |  |  |  |  |  | < 0.001 |
 Alive | 283 (66.1) | 45 (52.3) | 129 (73.7) | 77 (72.0) | 32 (53.3) | 238 (69.6) |  |
 Dead | 145 (33.9) | 41 (47.7) | 46 (26.3) | 30 (28.0) | 28 (46.7) | 104 (30.4) |  |