Table 1.
Baseline characteristics of the study patients
| With LLN metastasis | |||||
|---|---|---|---|---|---|
| Total | Yes | No | P | ||
| Subjects, n | 783 | 371 | 412 | – | |
| Gender | Male | 207 (26.4) | 115 (31.0) | 92 (22.3) | 0.006 |
| Female | 576 (73.6) | 256 (69.0) | 320 (77.7) | ||
| Age at diagnosis, years | 42.4 ± 13.1 | 41.0 ± 13.7 | 43.8 ± 12.3 | 0.005 | |
| Age group, years | ≤ 45 | 473 (60.0) | 242 (65.2) | 231 (56.1) | 0.009 |
| > 45 | 310 (40.0) | 129 (34.8) | 181 (43.9) | ||
| Tumor size, mm | 17.2 ± 11.1 | 20.8 ± 12.2 | 14.0 ± 9.0 | 0.001 | |
| Tumor size group | ≤ 10 | 306 (39.1) | 94 (25.3) | 212 (51.5) | 0.001 |
| 10–20 | 315 (40.0) | 161 (43.4) | 154 (37.4) | ||
| > 20 | 162 (20.9) | 116 (31.3) | 46 (11.1) | ||
| Tumor location | Upper lobe | 173 (22.1) | 105 (28.3) | 68 (16.5) | 0.001a |
| Middle lobe | 345 (44.1) | 155 (41.8) | 190 (46.1) | ||
| Lower lobe | 217 (27.7) | 75 (20.2) | 142 (34.4) | ||
| Isthmus | 19 (2.4) | 11 (3.0) | 8 (2.0) | ||
| Whole | 29 (3.7) | 25 (6.7) | 4 (1.0) | ||
| ETE | Yes | 157 (20.1) | 96 (25.9) | 61 (14.8) | 0.001 |
| No | 626 (79.9) | 275 (74.1) | 351 (85.2) | ||
| Multifocality | Yes | 94 (12.0) | 54 (14.6) | 40 (9.7) | 0.037 |
| No | 689 (88.0) | 317 (85.4) | 372 (90.3) | ||
| Bilaterality | Yes | 131 (16.7) | 75 (20.2) | 56 (13.6) | 0.013 |
| No | 652 (83.3) | 296 (79.8) | 356 (86.4) | ||
| Hashimoto’s thyroiditis | Yes | 92 (11.7) | 46 (12.4) | 46 (11.2) | 0.592 |
| No | 691 (88.3) | 325 (87.6) | 366 (88.8) | ||
| CLN metastases | < 2 | 383 (48.9) | 96 (25.9) | 287 (69.7) | 0.001 |
| ≥ 2 | 400 (51.1) | 275 (74.1) | 125 (30.3) | ||
Reported as n (%), unless noted otherwise. P values represent the statistically difference between the groups with and without LLN metastasis, unless noted otherwise
aThe P value means the difference among the upper lobe, middle lobe, lower lobe, isthmus, and hole thyroid lobe