Table 1 Baseline characteristics of patients before and after propensity score matching in the non-randomized arm
| Â | Non-randomized arm | ||||||
|---|---|---|---|---|---|---|---|
Pre-PS matching | Post-PS matching | Standardized difference | |||||
Surgery only (NR-Group S) n = 641 | Surgery plus UFT/LV (NR-Group U) n = 1,239 | Total (NR-Group) N = 1,880 | Surgery only (NR-Group S) n = 402 | Surgery plus UFT/LV (NR-Group U) n = 804 | Pre-PS matching | Post-PS matching | |
Agea, years | |||||||
 Mean ± SD | 69.9 ± 8.1 | 65.1 ± 9.9 | 66.7 ± 9.6 | 66.7 ± 8.5 | 64.4 ± 9.4 | — | — |
 Median [range] | 71 [34–80] | 66 [29–80] | 68 [29–80] | 67 [34–80] | 65 [29–80] | — | — |
  < 70 | 264 (41.2) | 771 (62.2) | 1,035 (55.1) | 264 (65.7) | 555 (69.0) | 0.431 | 0.072 |
  ≥ 70 | 377 (58.8) | 468 (37.8) | 845 (44.9) | 138 (34.3) | 249 (31.0) | — | — |
 Sexa, male | 369 (57.6) | 654 (52.8) | 1,023 (54.4) | 216 (53.7) | 454 (56.5) | 0.096 | 0.055 |
Risk factors for recurrencea | |||||||
 T4 disease | 302 (47.1) | 720 (58.1) | 1,022 (54.4) | 217 (54.0) | 460 (57.2) | 0.222 | 0.065 |
 Perforation/penetration | 52 (8.1) | 148 (11.9) | 200 (10.6) | 49 (12.2) | 116 (14.4) | 0.128 | 0.066 |
 Poorly differentiated adenocarcinoma | 46 (7.2) | 127 (10.3) | 173 (9.2) | 39 (9.7) | 87 (10.8) | 0.109 | 0.037 |
 Mucinous carcinoma | 72 (11.2) | 190 (15.3) | 262 (13.9) | 65 (16.2) | 120 (14.9) | 0.121 | 0.034 |
 No. of lymph nodes dissected < 12 | 298 (46.5) | 403 (32.5) | 701 (37.3) | 149 (37.1) | 269 (33.5) | 0.289 | 0.076 |
 No. of patients at institution ≥ 5 | 549 (85.6) | 969 (78.2) | 1,518 (80.7) | 331 (82.3) | 653 (81.2) | 0.194 | 0.029 |
Performance status | |||||||
 0 | 589 (91.9) | 1,175 (94.8) | 1,764 (93.8) | 367 (91.3) | 756 (94.0) | 0.119 | 0.105 |
 1 | 52 (8.1) | 64 (5.2) | 116 (6.2) | 35 (8.7) | 48 (6.0) | — | — |
Surgical approach | |||||||
 Laparoscopy | 404 (63.0) | 675 (54.5) | 1,079 (57.4) | 237 (59.0) | 430 (53.5) | 0.174 | 0.110 |
 Laparotomy | 237 (37.0) | 564 (45.5) | 801 (42.6) | 165 (41.0) | 374 (46.5) | — | — |
Histology | |||||||
 Papillary and tubular | 525 (81.9) | 928 (74.9) | 1,453 (77.3) | 300 (74.6) | 602 (74.9) | 0.171 | 0.006 |
 Poorly differentiated and other | 116 (18.1) | 311 (25.1) | 427 (22.7) | 102 (25.4) | 202 (25.1) | — | — |
Depth of tumor invasion (TNM classification) | |||||||
 T3 | 339 (52.9) | 519 (41.9) | 858 (45.6) | 185 (46.0) | 344 (42.8) | 0.222 | 0.065 |
 T4 | 302 (47.1) | 720 (58.1) | 1,022 (54.4) | 217 (54.0) | 460 (57.2) | — | — |
Lymph node dissection | |||||||
 Mean ± SD | 17.9 ± 13.3 | 21.0 ± 14.3 | 20.0 ± 14.0 | 19.9 ± 14.0 | 20.7 ± 13.7 | 0.228 | 0.055 |
 Median [range] | 13 [1–107] | 18 [1–129] | 17 [1–129] | 16 [1–107] | 18 [1–89] | — | — |
Lymphatic invasion | |||||||
 Ly0 | 285 (44.5) | 501 (40.4) | 786 (41.8) | 170 (42.3) | 321 (39.9) | 0.081b | 0.048 |
  ≥ Ly1 | 356 (55.5) | 737 (59.5) | 1,093 (58.1) | 232 (57.7) | 483 (60.1) | — | — |
 Missing | 0 (0.0) | 1 (0.1) | 1 (0.1) | 0 (0.0) | 0 (0.0) | — | — |
Venous invasion | |||||||
 V0 | 235 (36.7) | 400 (32.3) | 635 (33.8) | 149 (37.1) | 256 (31.8) | 0.092b | 0.110 |
  ≥ V1 | 406 (63.3) | 838 (67.6) | 1,244 (66.2) | 253 (62.9) | 548 (68.2) | — | — |
 Missing | 0 (0.0) | 1 (0.1) | 1 (0.1) | 0 (0.0) | 0 (0.0) | — | — |
Tumor location | |||||||
 Right colon (C, A, T) | 253 (39.5) | 550 (44.4) | 803 (42.7) | 167 (41.5) | 355 (44.2) | 0.100 | 0.053 |
 Left colon (D, S, RS) | 388 (60.5) | 689 (55.6) | 1,077 (57.3) | 235 (58.5) | 449 (55.8) | — | — |