Table 1. Patient characteristics.
| Characteristics | Total (N=475) | BSA ≤1.73 m2 (N=239) | BSA >1.73 m2 (N=236) | P value |
|---|---|---|---|---|
| Basic information | ||||
| Mean age, years (SD) | 62.67±8.52 | 63.31±8.32 | 62.03±8.69 | 0.10 |
| Gender (Male, %) | 278 (58.5) | 83 (34.7) | 195 (82.6) | <0.001 |
| Mean height, cm (SD) | 161.42±7.88 | 156.55±6.30 | 166.35±6.05 | <0.001 |
| Mean weight, kg (SD) | 61.58±10.10 | 53.82±5.33 | 69.45±7.32 | <0.001 |
| Body mass index, kg/m2 | ||||
| Mean ± SD | 23.59±3.07 | 22.08±2.47 | 25.12±2.84 | <0.001 |
| Median (range) | 23.42 (15.62–31.64) | 21.94 (16.65–29.33) | 25.0 (15.62–31.64) | |
| BSA, m2 | ||||
| Mean ± SD | 1.74±0.16 | 1.61±0.08 | 1.87±0.11 | <0.001 |
| Median (range) | 1.73 (1.31–2.18) | 1.63 (1.31–1.73) | 1.83 (1.73–2.18) | |
| Smoking history, n (%) | 227 (47.8) | 76 (31.8) | 151 (64.0) | <0.001 |
| Preoperative underlying comorbidities, n (%) | ||||
| COPD | 110 (23.2) | 54 (22.6) | 56 (23.7) | 0.77 |
| Tuberculosis | 39 (8.2) | 20 (8.4) | 19 (8.1) | 0.90 |
| Preoperative respiratory infection | 43 (9.1) | 20 (8.4) | 23 (9.7) | 0.60 |
| Hypertension | 168 (35.4) | 75 (31.4) | 93 (39.4) | 0.067 |
| Diabetes mellitus | 51 (10.7) | 23 (9.6) | 28 (11.9) | 0.43 |
| Coronary heart disease | 55 (11.6) | 23 (9.6) | 32 (13.6) | 0.18 |
| Renal insufficiency | 34 (7.2) | 19 (7.9) | 15 (6.4) | 0.50 |
| Severe liver diseases | 51 (10.7) | 23 (9.6) | 28 (11.9) | 0.43 |
| Previous malignancy | 28 (5.9) | 14 (5.9) | 14 (5.9) | 0.97 |
| Steroid use | 22 (4.6) | 13 (5.4) | 9 (3.8) | 0.40 |
| Combined treatment modalities, n (%) | ||||
| Neoadjuvant induction therapy | 35 (7.4) | 12 (5.0) | 23 (9.7) | 0.054 |
| Adjuvant chemotherapy | 161 (33.9) | 63 (26.4) | 98 (41.5) | <0.001 |
| Intraoperative parameters, n (%) | ||||
| Tumor location | ||||
| Right upper lobe | 163 (34.3) | 87 (36.4) | 76 (32.2) | 0.28 |
| Left upper lobe | 94 (19.8) | 53 (22.2) | 41 (17.4) | |
| Right lower lobe | 99 (20.8) | 46 (19.2) | 53 (22.5) | |
| Left lower lobe | 66 (13.9) | 32 (13.4) | 34 (14.4) | |
| Right middle lobe | 53 (11.2) | 21 (8.8) | 32 (13.6) | |
| Pleural invasion | ||||
| None | 223 (46.9) | 124 (51.9) | 99 (41.9) | 0.071 |
| Visceral | 219 (46.1) | 102 (42.7) | 117 (49.6) | |
| Parietal | 33 (6.9) | 13 (5.4) | 20 (8.5) | |
| Pleural adhesion | ||||
| None | 205 (43.2) | 99 (41.4) | 106 (44.9) | 0.83 |
| Light | 148 (31.2) | 78 (32.6) | 70 (29.7) | |
| Moderate | 79 (16.6) | 39 (16.3) | 40 (16.9) | |
| Severe/atresia | 43 (9.1) | 23 (9.6) | 20 (8.5) | |
| Pulmonary fissure status | ||||
| Complete fissures | 318 (66.9) | 164 (68.6) | 154 (65.3) | 0.44 |
| Incomplete fissures | 157 (33.1) | 75 (33.1) | 82 (31.7) | |
| Conversion to thoracotomy | 16 (3.4) | 3 (1.3) | 13 (5.5) | 0.010 |
| Pathologic parameters, n (%) | ||||
| Histology | ||||
| Adenocarcinoma | 365 (76.8) | 186 (77.8) | 179 (75.8) | 0.40 |
| Squamous cell carcinoma | 88 (18.5) | 40 (16.7) | 48 (20.3) | |
| Adeno-squamous carcinoma | 13 (2.7) | 9 (3.8) | 4 (1.7) | |
| Others | 9 (1.9) | 4 (1.7) | 5 (2.1) | |
| Differentiation degree | ||||
| Low | 84 (17.7) | 39 (16.3) | 45 (19.1) | 0.43 |
| Moderate/high | 391 (82.3) | 200 (83.7) | 191 (80.9) | |
| Tumor invasion (T status) | ||||
| T1-2 | 452 (95.2) | 232 (97.1) | 220 (93.2) | 0.051 |
| T3-4 | 23 (4.8) | 7 (2.9) | 16 (6.8) | |
| Lymph node metastasis (N status) | ||||
| N1-2 | 98 (20.6) | 29 (12.1) | 69 (29.2) | <0.001 |
| N0 | 377 (79.4) | 210 (87.9) | 167 (70.8) | |
| TNM stage | ||||
| I | 349 (73.4) | 194 (81.1) | 155 (64.8) | <0.001 |
| II | 70 (14.7) | 35 (14.6) | 35 (14.8) | |
| IIIa | 56 (11.8) | 10 (4.2) | 46 (19.5) | |
BSA, body surface area; COPD, chronic obstructive pulmonary disease; SD, standard deviation.