Table 1.
Basic characteristics of the total cohort and the propensity score-matched cohort
| Total cohort | Propensity score-matched cohort | |||||
|---|---|---|---|---|---|---|
| <15 lymph nodes | ≥15 lymph nodes | SMD | <15 lymph nodes | ≥15 lymph nodes | SMD | |
| Total | 1021 | 2260 | 992 | 992 | ||
| Sex | ||||||
| Male | 809 (79.2) | 1756 (77.7) | 0.037 | 783 (78.9) | 776 (78.2) | 0.017 |
| Female | 212 (20.8) | 504 (22.3) | 209 (21.1) | 216 (21.8) | ||
| Age, years [mean (SD)] | 65.50 (8.62) | 64.25 (8.77) | 0.144 | 65.28 (8.57) | 65.30 (8.63) | 0.002 |
| ASA score | ||||||
| I | 156 (15.3) | 422 (18.7) | 0.124 | 155 (15.6) | 154 (15.5) | 0.052 |
| II | 622 (60.9) | 1372 (60.7) | 607 (61.2) | 601 (60.6) | ||
| III | 231 (22.6) | 453 (20.0) | 220 (22.2) | 230 (23.2) | ||
| IV | 3 (0.3) | 6 (0.3) | 3 (0.3) | 1 (0.1) | ||
| Unknown | 9 (0.9) | 7 (0.3) | 7 (0.7) | 6 (0.6) | ||
| Charlson comorbidity score | ||||||
| 0 | 483 (47.3) | 1153 (51.0) | 0.091 | 473 (47.7) | 471 (47.5) | 0.064 |
| 1 | 258 (25.3) | 572 (25.3) | 251 (25.3) | 275 (27.7) | ||
| 2+ | 280 (27.4) | 535 (23.7) | 268 (27.0) | 246 (24.8) | ||
| Body mass index | ||||||
| < 20 | 69 (6.8) | 145 (6.4) | 0.07 | 68 (6.9) | 60 (6.0) | 0.056 |
| 20–24 | 380 (37.2) | 862 (38.1) | 366 (36.9) | 374 (37.7) | ||
| 25–29 | 387 (37.9) | 890 (39.4) | 377 (38.0) | 392 (39.5) | ||
| 29+ | 170 (16.7) | 342 (15.1) | 166 (16.7) | 153 (15.4) | ||
| Unknown | 15 (1.5) | 21 (0.9) | 15 (1.5) | 13 (1.3) | ||
| Weight loss (anamnestic) | ||||||
| < 10 kg | 731 (71.6) | 1763 (78.0) | 0.195 | 714 (72.0) | 723 (72.9) | 0.045 |
| 10.1–15 kg | 77 (7.5) | 139 (6.2) | 74 (7.5) | 65 (6.6) | ||
| > 15 kg | 40 (3.9) | 113 (5.0) | 39 (3.9) | 44 (4.4) | ||
| Unknown | 173 (16.9) | 245 (10.8) | 165 (16.6) | 160 (16.1) | ||
| Tumor location | ||||||
| Proximal/mid thoracic | 105 (10.3) | 357 (15.8) | 0.209 | 105 (10.6) | 111 (11.2) | 0.053 |
| Distal | 663 (64.9) | 1490 (65.9) | 654 (65.9) | 629 (63.4) | ||
| Gastroesophageal junction | 253 (24.8) | 413 (18.3) | 233 (23.5) | 252 (25.4) | ||
| cT category | ||||||
| cT0-1 | 17 (1.7) | 26 (1.2) | 0.073 | 16 (1.6) | 10 (1.0) | 0.059 |
| cT2 | 212 (20.8) | 425 (18.8) | 202 (20.4) | 197 (19.9) | ||
| cT3 | 736 (72.1) | 1679 (74.3) | 720 (72.6) | 727 (73.3) | ||
| cT4 | 35 (3.4) | 74 (3.3) | 33 (3.3) | 37 (3.7) | ||
| cTx/Unknown | 21 (2.1) | 56 (2.5) | 21 (2.1) | 21 (2.1) | ||
| cN category | ||||||
| cN0 | 365 (35.7) | 724 (32.0) | 0.104 | 350 (35.3) | 352 (35.5) | 0.048 |
| cN1 | 446 (43.7) | 987 (43.7) | 435 (43.9) | 448 (45.2) | ||
| cN2 | 177 (17.3) | 464 (20.5) | 174 (17.5) | 164 (16.5) | ||
| cN3 | 22 (2.2) | 61 (2.7) | 22 (2.2) | 17 (1.7) | ||
| cN4 | 11 (1.1) | 24 (1.1) | 11 (1.1) | 11 (1.1) | ||
| cM category | ||||||
| cM0 | 990 (97.0) | 2208 (97.7) | 0.051 | 961 (96.9) | 968 (97.6) | 0.048 |
| cM+ | 6 (0.6) | 13 (0.6) | 6 (0.6) | 6 (0.6) | ||
| cMx/Unknown | 25 (2.4) | 39 (1.7) | 25 (2.5) | 18 (1.8) | ||
| Histological type | ||||||
| Adenocarcinoma | 728 (71.3) | 1554 (68.8) | 0.073 | 705 (71.1) | 721 (72.7) | 0.075 |
| Squamous cell carcinoma | 164 (16.1) | 423 (18.7) | 162 (16.3) | 149 (15.0) | ||
| Other | 19 (1.9) | 43 (1.9) | 18 (1.8) | 15 (1.5) | ||
| Not applicable | 81 (7.9) | 183 (8.1) | 80 (8.1) | 88 (8.9) | ||
| Unknown | 29 (2.8) | 57 (2.5) | 27 (2.7) | 19 (1.9) | ||
| Differentiation grade | ||||||
| Well/moderate | 358 (35.1) | 868 (38.4) | 0.092 | 348 (35.1) | 350 (35.3) | 0.059 |
| Poor | 276 (27.0) | 600 (26.5) | 269 (27.1) | 277 (27.9) | ||
| Not judgeable | 184 (18.0) | 340 (15.0) | 176 (17.7) | 155 (15.6) | ||
| Unknown | 203 (19.9) | 452 (20.0) | 199 (20.1) | 210 (21.2) | ||
| Year of surgery | ||||||
| 2011 | 202 (19.8) | 189 (8.4) | 0.482 | 179 (18.0) | 146 (14.7) | 0.145 |
| 2012 | 187 (18.3) | 287 (12.7) | 181 (18.2) | 193 (19.5) | ||
| 2013 | 188 (18.4) | 322 (14.2) | 188 (19.0) | 169 (17.0) | ||
| 2014 | 150 (14.7) | 429 (19.0) | 150 (15.1) | 190 (19.2) | ||
| 2015 | 167 (16.4) | 504 (22.3) | 167 (16.8) | 155 (15.6) | ||
| 2016 | 127 (12.4) | 529 (23.4) | 127 (12.8) | 139 (14.0) | ||
| Resection margins (pathological) | ||||||
| pR0 | 962 (94.2) | 2152 (95.2) | 0.047 | 935 (94.3) | 944 (95.2) | 0.05 |
| pR+ | 47 (4.6) | 89 (3.9) | 46 (4.6) | 41 (4.1) | ||
| Unknown | 12 (1.2) | 19 (0.8) | 11 (1.1) | 7 (0.7) | ||
| Other characteristics (matching not based on these variables) | ||||||
| Procedure | ||||||
| TTE (thoracic open) | 149 (14.6) | 402 (17.8) | 0.843 | 148 (14.9) | 167 (16.8) | 0.7 |
| TTE (thoracic MI) | 308 (30.2) | 1426 (63.1) | 307 (30.9) | 592 (59.7) | ||
| THE (open) | 441 (43.2) | 296 (13.1) | 417 (42.0) | 163 (16.4) | ||
| THE (MI) | 116 (11.4) | 133 (5.9) | 113 (11.4) | 68 (6.9) | ||
| Unknown | 7 (0.7) | 3 (0.1) | 7 (0.7) | 2 (0.2) | ||
| Annual hospital volume | ||||||
| 0–25 | 226 (22.1) | 187 (8.3) | 0.446 | 223 (22.5) | 86 (8.7) | 0.426 |
| 26–50 | 527 (51.6) | 1304 (57.7) | 511 (51.5) | 578 (58.3) | ||
| 50+ | 250 (24.5) | 765 (33.8) | 240 (24.2) | 324 (32.7) | ||
| Stopped with esophageal surgery before 2014 | 18 (1.8) | 4 (0.2) | 18 (1.8) | 4 (0.4) | ||
Data are expressed as n (%) unless otherwise specified
SMD standard mean difference, SD standard deviation, ASA American Society of Anesthesiologists, TTE trans-thoracic esophagectomy, THE transhiatal esophagectomy, MI myocardial infarction