Baseline characteristics of the study population
| Variable | Number (n=262), % |
| Age in years (mean ± SD) | 69.7 ± 8.7 |
| Gender, male | 118 (45) |
| Smoking status: | |
| Non | 12 (4.58) |
| Ex | 119 (45.4) |
| Current | 55 (20.1) |
| Unknown | 76 (29.0) |
| Performance status | |
| 0 | 85 (32.4) |
| 1 | 115 (43.9) |
| 2 | 6 (2.29) |
| Unknown | 56 (21.4) |
| Tumour size in mm | 34.9 ± 21.2 |
| Stage: | |
| Ia | 71 (27.0) |
| Ib | 75 (28.6) |
| IIa | 37 (14.1) |
| IIb | 21 (8.02) |
| IIIa | 58 (22.1) |
| Operation type: | |
| Lobectomy | 232 (88.6) |
| Segmentectomy | 9 (3.44) |
| Pneumonectomy | 10 (3.82) |
| Bilobectomy | 11 (4.20) |
| Presence of invasion: | |
| Mediastinal | 2 (0.76) |
| Chest wall | 5 (1.91) |
| Visceral pleural | 103 (39.3) |
| Parietal pleural | 13 (4.96) |
| Lymphovascular | 110 (42.0) |
| Intra-alveolar spread (stas) | 50 (19.1) |
| Adenocarcinoma subtype: | |
| Lepidic | 55 (20.99) |
| Acinar | 98 (37.40) |
| Papillary | 24 (9.16) |
| Micropapillary | 48 (18.32) |
| Solid | 37 (14.12) |