Table 1. General characteristics and association between patients’ characteristics and lymph node metastasis.
| Variables | Total (1,543) | pN0 (n=1,412) | pN1 + pN2 (n=131) | t/χ2 | P value |
|---|---|---|---|---|---|
| Age (years) | 57.96±8.59 | 57.86±8.62 | 59.03±8.33 | −1.488 | 0.137 |
| ≤40 | 42 | 39 | 3 | 3.241 | 0.514 |
| 41–50 | 259 | 242 | 17 | ||
| 51–60 | 586 | 533 | 53 | ||
| 61–70 | 557 | 511 | 46 | ||
| ≥71 | 99 | 87 | 12 | ||
| Sex | 10.546 | 0.001 | |||
| Male | 710 | 632 | 78 | ||
| Female | 833 | 780 | 53 | ||
| Smoking history | 274.504 | <0.001 | |||
| Never | 1,374 | 1,314 | 60 | ||
| Current/former | 169 | 98 | 71 | ||
| Tumor location | 2.913 | 0.580 | |||
| RUL | 532 | 494 | 38 | ||
| RML | 100 | 93 | 7 | ||
| RLL | 311 | 283 | 28 | ||
| LUL | 367 | 330 | 37 | ||
| LLL | 233 | 212 | 21 | ||
| CT characters | 62.593 | <0.001 | |||
| GGO | 406 | 406 | 0 | ||
| P-GS | 252 | 238 | 14 | ||
| Solid | 885 | 769 | 116 | ||
| Tumor size (cm) | 67.161 | <0.001 | |||
| ≤0.5 | 20 | 20 | 0 | ||
| 0.5–1 | 264 | 260 | 4 | ||
| 1.1–1.5 | 429 | 409 | 20 | ||
| 1.6–2.0 | 336 | 307 | 29 | ||
| 2.1–2.5 | 290 | 252 | 38 | ||
| 2.6–3.0 | 204 | 164 | 40 | ||
| Histologic type | 1.322 | 0.531 | |||
| Adenocarcinoma | 1,321 | 1,213 | 108 | ||
| SCC | 189 | 170 | 19 | ||
| Others | 33 | 29 | 4 | ||
| Differentiation | 107.344 | <0.001 | |||
| Well | 477 | 471 | 6 | ||
| Moderate | 760 | 703 | 57 | ||
| Poor | 306 | 238 | 68 | ||
| VPI | 161.879 | <0.001 | |||
| Yes | 180 | 120 | 60 | ||
| No | 1,363 | 1,292 | 71 | ||
| LVI | 331.739 | <0.001 | |||
| Yes | 95 | 39 | 56 | ||
| No | 1,448 | 1,373 | 75 |
GGO, ground-glass opacity; VPI, visceral pleural invasion; LVI, lymphovascular invasion; P-GS, partially GGO-solid tumors; RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe; LUL, left upper lobe; LLL, left lower lobe; SCC, squamous cell carcinoma.