Table 1.
Characteristics of patients in different groups according to total mesorectal excision (TME) quality.
| Variables | Before PSM | After PSM | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Grade A | Grade B | Grade C | P | *Grade B/C | P | Grade A | Grade B/C | P | |
| Sex | 0.332 | 0.688 | 0.852 | ||||||
| Female | 311 (60.5) | 42 (38.9) | 14 (53.8) | 56 (58.2) | 167 (40.9) | 54 (41.9) | |||
| Male | 476 (39.5) | 66 (61.1) | 12 (46.2) | 78 (41.8) | 241 (59.1) | 75 (58.1) | |||
| Age (years) | 0.348 | 0.175 | 0.173 | ||||||
| ≤60 | 481 (61.1) | 59 (54.6) | 14 (53.8) | 73 (54.5) | 249 (61.0) | 70 (54.3) | |||
| >60 | 306 (38.9) | 49 (45.4) | 12 (46.2) | 61 (45.5) | 159 (39.0) | 59 (45.7) | |||
| BMI (kg/m2) | 0.656 | 1.000 | 0.516 | ||||||
| ≤25 | 596 (75.7) | 84 (77.8) | 18 (69.2) | 102 (76.1) | 318 (77.9) | 97 (75.2) | |||
| >25 | 191 (24.3) | 24 (22.2) | 8 (30.8) | 32 (23.9) | 90 (22.1) | 32 (24.8) | |||
| ASA score | 0.158 | 0.226 | 0.270 | ||||||
| I | 563 (71.5) | 75 (69.4) | 14 (53.8) | 89 (66.4) | 293 (71.8) | 86 (66.7) | |||
| II | 215 (27.3) | 31 (28.7) | 12 (46.2) | 43 (32.1) | 109 (26.7) | 41 (31.8) | |||
| III | 9 (1.1) | 2 (1.9) | 0 (0.0) | 2 (1.5) | 6 (1.5) | 2 (1.6) | |||
| CA19-9 (U/ml) | 0.388 | 1.000 | 1.000 | ||||||
| ≤37 | 760 (96.6) | 105 (94.2) | 24 (92.3) | 129 (96.3) | 392 (96.1) | 124 (96.1) | |||
| >37 | 27 (3.4) | 3 (2.8) | 2 (7.7) | 5 (3.7) | 16 (3.9) | 5 (3.9) | |||
| CEA (ng/ml) | 0.185 | 0.426 | 0.712 | ||||||
| ≤5 | 676 (85.9) | 92 (85.2) | 19 (73.1) | 111 (82.8) | 344 (84.3) | 107 (82.9) | |||
| >5 | 111 (14.1) | 16 (14.8) | 7 (26.9) | 23 (17.2) | 64 (15.7) | 22 (17.1) | |||
| Distance to the anal verge (mm) | 50.7±15.9 | 43.7±15.1 | 43.9±15.5 | <0.001 | 43.7±15.3 | <0.001 | 46.9±16.9 | 44.3±15.1 | 0.158 |
| Surgery method | 0.777 | 0.905 | 0.550 | ||||||
| Laparoscopic | 521 (66.2) | 74 (68.5) | 16 (61.5) | 90 (67.2) | 257 (63.0) | 85 (65.9) | |||
| Open | 266 (33.8) | 34 (31.5) | 10 (38.5) | 44 (32.8) | 151 (37.0) | 44 (34.0) | |||
| Sphincter preservation | <0.001 | <0.001 | 0.055 | ||||||
| Yes | 602 (76.5) | 47 (43.5) | 12 (46.2) | 59 (44.0) | 226 (55.4) | 59 (45.7) | |||
| No | 185 (23.5) | 61 (56.5) | 14 (53.8) | 75 (56.0) | 182 (44.6) | 70 (54.3) | |||
| nCRT | 0.691 | 0.494 | 0.473 | ||||||
| Yes | 525 (66.7) | 75 (69.4) | 19 (73.1) | 94 (70.1) | 274 (67.2) | 91 (70.5) | |||
| No | 262 (33.3) | 33 (30.6) | 7 (26.9) | 40 (29.9) | 134 (32.8) | 38 (29.5) | |||
| Central group lymph node status | 0.458 | 0.626 | 0.676 | ||||||
| Negative | 780 (99.1) | 106 (98.1) | 26 (100.0) | 132 (98.5) | 403 (98.8) | 127 (98.4) | |||
| Positive | 7 (0.9) | 2 (1.9) | 0 (0.0) | 2 (1.5) | 5 (1.2) | 2 (1.6) | |||
| pT stage | 0.423 | 0.426 | 0.662 | ||||||
| T0/Tis | 116 (14.7) | 13 (12.0) | 5 (19.2) | 18 (13.4) | 61 (15.0) | 17 (13.2) | |||
| T1 | 77 (9.8) | 6 (5.6) | 1 (3.8) | 7 (5.2) | 31 (7.6) | 7 (5.4) | |||
| T2 | 267 (33.9) | 41 (38.0) | 11 (42.3) | 52 (38.8) | 147 (36.0) | 52 (40.3) | |||
| T3 | 284 (36.1) | 40 (37.0) | 8 (30.8) | 48 (35.8) | 149 (36.5) | 45 (34.9) | |||
| T4 | 43 (5.5) | 8 (7.4) | 1 (3.8) | 9 (6.7) | 20 (4.9) | 8 (6.2) | |||
| pN stage | 0.274 | 0.179 | 0.748 | ||||||
| N0 | 595 (75.6) | 74 (68.5) | 20 (76.9) | 94 (70.1) | 300 (73.5) | 93 (72.1) | |||
| N+ | 192 (24.4) | 34 (31.5) | 6 (23.1) | 40 (29.9) | 108 (26.5) | 36 (27.9) | |||
| pTNM stage | 0.391 | 0.254 | 0.711 | ||||||
| 0 | 112 (14.2) | 12 (11.1) | 4 (15.4) | 16 (11.9) | 57 (14.0) | 16 (12.4) | |||
| I | 278 (35.3) | 37 (34.3) | 9 (34.6) | 46 (34.3) | 143 (35.0) | 46 (35.7) | |||
| II | 205 (26.0) | 25 (23.1) | 7 (26.9) | 32 (23.9) | 100 (24.5) | 31 (24.0) | |||
| III | 192 (24.4) | 34 (31.5) | 6 (23.1) | 40 (29.9) | 108 (26.5) | 36 (27.9) | |||
*Compare with Grade A.
Abbreviations: BMI, body mass index; ASA, American Society of Anesthesiologists Score; CEA, circumferential resection margin; CA19-9, carbohydrate antigen 19-9; nCRT, neoadjuvant chemoradiotherapy.