Table 1.
Baseline characteristics grouped by smoking history
| Smoker (%) | Non‐smoker (%) | P valuea | |
|---|---|---|---|
| Gender | <0.05 | ||
| Male | 377 (96.9) | 77 (30.3) | |
| Female | 12 (3.1) | 177 (69.7) | |
| Age (years) | 0.074 | ||
| <40 | 15 (3.9) | 18 (7.1) | |
| 40–60 | 252 (64.8) | 146 (57.5) | |
| >60 | 122 (31.4) | 90 (35.4) | |
| Alcohol consumption | 111 (28.5) | 10 (3.9) | <0.05 |
| Family history | 27 (6.9) | 19 (7.3) | 0.876 |
| Tumor location | 0.021a | ||
| Upper thoracic | 49 (12.6) | 22 (8.7) | |
| Middle thoracic | 264 (67.9) | 198 (78) | |
| Lower thoracic | 76 (19.5) | 34 (13.4) | |
| Postoperative stage | 0.012a | ||
| IA | 21 (5.4) | 27 (10.6) | |
| IB | 178 (45.8) | 126 (49.6) | |
| IIA | 190 (48.8) | 101 (39.8) | |
| Tumor grade of differentiation | 0.212 | ||
| Well | 140 (36.1) | 101 (39.8) | |
| Moderately | 172 (44.3) | 95 (37.4) | |
| Poorly | 76 (19.6) | 58 (22.8) | |
| Surgical incision | 0.112 | ||
| Left thoracic | 302 (77.7) | 197 (77.5) | |
| Right thoracic | 87 (22.4) | 57 (22.4) | |
| Postoperative radiotherapy | 10 (2.6) | 3 (1.2) | 0.264 |
| Three‐field surgical dissection | 55 (14.1) | 44 (17.3) | 0.285 |
a
P < 0.05 was considered statistically significant.