Table 1.
Baseline characteristics according to tumor location of non-small cell lung cancer patients.
| Variable | Non-lower lobe (n = 1,378) | Lower lobe (n = 911) | P value |
|---|---|---|---|
| Age, % (n = 2,289) | 0.270 | ||
| < 40 year | 21 (1.5%) | 14 (1.5%) | |
| 40–59 year | 339 (24.6%) | 207 (22.7%) | |
| 60–79 year | 936 (67.9%) | 618 (67.8%) | |
| ≥ 80 year | 82 (6.0%) | 72 (7.9%) | |
| Male, % (n = 2,289) | 502 (36.4%) | 329 (36.1%) | 0.913 |
| Degree of obesity, % (n = 2,289) | 0.873 | ||
| Underweight, BMI < 18.5 kg/m2 | 82 (6.0%) | 54 (5.9%) | |
| Normal, BMI = 18.5–22.9 kg/m2 | 539 (39.1%) | 359 (39.5%) | |
| Overweight, BMI = 23.0–24.9 kg/m2 | 353 (25.6%) | 220 (24.2%) | |
| Obese, BMI ≥ 25.0 kg/m2 | 404 (29.3%) | 277 (30.4%) | |
| Smoking status, % (n = 2,289) | 0.865 | ||
| Ever smoking | 847 (61.5%) | 564 (61.9%) | |
| ECOG,% (n = 2,289) | 0.108 | ||
| 0 | 641 (46.5%) | 380 (41.7%) | |
| 1 | 590 (42.8%) | 412 (45.2%) | |
| 2 | 113 (8.2%) | 93 (10.2%) | |
| 3 | 30 (2.2%) | 25 (2.7%) | |
| 4 | 4 (0.3%) | 1 (0.1%) | |
| Respiratory symptoms at diagnosis, % (n = 2,289) | 679 (49.3%) | 466 (51.2%) | 0.403 |
| Pulmonary function test (n = 2,028) | |||
| FEV1% of predicted | 98.0 ± 22.6 | 97.7 ± 22.7 | 0.760 |
| FVC % of predicted | 97.1 ± 16.9 | 95.9 ± 17.5 | 0.128 |
| FEV1/FVC % | 71.1 ± 11.6 | 71.3 ± 11.2 | 0.745 |
| Pathology, % (n = 2,289) | 0.011 | ||
| Adenocarcinoma | 922 (66.9%) | 554 (60.8%) | |
| Squamous cell carcinoma | 326 (23.7%) | 260 (28.5%) | |
| Others | 130 (9.4%) | 97 (10.6%) | |
| Stage, % (n = 2,289) | 0.133 | ||
| I | 440 (31.9%) | 274 (30.1%) | |
| II | 145 (10.5%) | 112 (12.3%) | |
| III | 326 (23.7%) | 189 (20.7%) | |
| IV | 467 (33.9%) | 336 (36.9%) | |
| SUV of main mass (n = 2,063) | 12.2 ± 7.2 | 11.7 ± 7.4 | 0.099 |
| EBUS-TBNA (n = 2,289) | 371 (26.9%) | 267 (29.3%) | 0.231 |
| Tumor markers | |||
| NSE, ng/mL (n = 1,059) | 21.7 ± 16.7 | 26.2 ± 31.7 | 0.003 |
| CEA, ng/mL (n = 1,962) | 54.4 ± 385.7 | 34.7 ± 181.2 | 0.182 |
| CYFRA 21-1, ng/mL (n = 1,740) | 6.0 ± 17.4 | 7.9 ± 17.1 | 0.026 |
| EGFR mutations, % (n = 1,672) | 438 (42.6%) | 221 (34.4%) | 0.001 |
| Exon 18, % | 23 (2.2%) | 11 (1.7%) | 0.569 |
| Exon 19, % | 193 (18.7%) | 120 (18.7%) | 1.000 |
| Exon 20, % | 22 (2.1%) | 12 (1.9%) | 0.831 |
| Exon 21, % | 214 (20.8%) | 86 (13.4%) | < 0.001 |
| ALK translocation, % (n = 1,678) | 46 (4.5%) | 39 (6.0%) | 0.199 |
| Active treatment, % (n = 2,289) | 1,309 (95.0%) | 855 (93.9%) | 0.280 |
ALK anaplastic lymphoma kinase; BMI body mass index; CEA carcinoembryonic antigen; CYFRA cytokeratin fragment; EBUS-TBNA endobronchial ultrasound-guided transbronchial needle aspirate; ECOG Eastern Cooperative Oncology Group; EGFR epidermal growth factor receptor; FEV1 forced expiratory volume in 1 second; FVC forced vital capacity; NSE neuron-specific enolase; SUV standardized uptake value.