Table 1.
Characteristics of patients in the development group.
| Patients with negative LNs (%) | Patients with positive N1 nodes (%) | Patients with positive N2 nodes (%) | p value∗ | |
|---|---|---|---|---|
| Age (year) | 59.1 ± 9.7 | 58.1 ± 10.0 | 58.9 ± 10.4 | 0.742 |
| Gender | ||||
| Male | 346 (85.4) | 21 (5.2) | 38 (9.4) | 0.011 |
| Female | 478 (92.1) | 9 (1.7) | 32 (6.2) | |
| Symptoms | ||||
| RCE | 456 (91.9) | 8 (1.6) | 32 (6.5) | 0.010 |
| RCRS | 256 (85.6) | 16 (5.4) | 27 (9.0) | |
| ICD | 112 (86.8) | 6 (4.7) | 11 (8.5) | |
| Asymptomatic | 568 (90.9) | 14 (2.2) | 43 (6.9) | 0.008 |
| Symptomatic | 256 (85.6) | 16 (5.4) | 27 (9.0) | |
| Cancer history | ||||
| Yes | 58 (85.3) | 4 (5.9) | 6 (8.8) | 0.454 |
| No | 766 (89.5) | 26 (3.0) | 64 (7.5) | |
| Family history of cancer | ||||
| Yes | 122 (91.0) | 1 (0.8) | 11 (8.2) | 0.169 |
| No | 702 (88.9) | 29 (3.7) | 59 (7.4) | |
| Pathology | ||||
| Adenocarcinoma | 760 (91.2) | 16 (1.9) | 57 (6.9) | <0.001 |
| Squamous | 52 (75.4) | 10 (14.5) | 7 (10.1) | |
| Adenosquamous | 3 (37.5) | 1 (12.5) | 4 (50.0) | |
| Neuroendocrine | 8 (66.7) | 3 (25.0) | 1 (8.3) | |
| Other tumor type | 1 (50.0) | 0 (0.0) | 1 (50.0) | |
| Smoking history | ||||
| Yes | 220 (85.3) | 17 (6.6) | 21 (8.1) | 0.001 |
| No | 604 (90.7) | 13 (2.0) | 49 (7.3) | |
| Location | ||||
| Upper lobe | 445 (90.1) | 14 (2.8) | 35 (7.1) | 0.670 |
| Lower lobe | 270 (88.8) | 9 (3.0) | 25 (8.2) | |
| Middle lobe | 109 (86.5) | 7 (5.6) | 10 (7.9) | |
| Central | 316 (86.6) | 18 (4.9) | 31 (8.5) | 0.042 |
| Peripheral | 508 (90.9) | 12 (2.1) | 39 (7.0) | |
| Nodule size on CT | ||||
| Tumor size (cm) | 1.63 ± 0.59 | 2.25 ± 0.57 | 2.33 ± 0.50 | <0.001 |
| Consolidation size (cm) | 0.91 ± 0.83 | 2.19 ± 0.69 | 2.22 ± 0.59 | <0.001 |
| C/T ratio | 0.51 ± 0.41 | 0.95 ± 0.19 | 0.95 ± 0.15 | <0.001 |
| Chronic pulmonary disease | ||||
| Yes | 68 (78.2) | 8 (9.2) | 11 (12.6) | 0.001 |
| No | 756 (90.3) | 22 (2.6) | 59 (7.1) | |
| Clinical nodal stage on CT | ||||
| Enlarged LNs in N2 station | 72 (64.3) | 7 (6.3) | 33 (29.4) | <0.001 |
| Enlarged LNs in N1 station | 10 (38.5) | 6 (23.0) | 10 (38.5) | |
| Normal-sized LNs | 742 (94.4) | 17 (2.2) | 27 (3.4) | |
| Levels of tumor markers | ||||
| CEA (ng/ml) | 3.26 ± 4.84 | 3.55 ± 2.56 | 10.21 ± 17.58 | <0.001 |
| AFP (ng/ml) | 3.03 ± 1.80 | 2.68 ± 0.89 | 3.25 ± 2.71 | 0.542 |
| CA199 (U/ml) | 10.48 ± 15.24 | 9.99 ± 9.26 | 15.67 ± 17.16 | 0.013 |
| CA125 (U/ml) | 11.31 ± 11.22 | 13.23 ± 10.04 | 26.53 ± 77.33 | 0.093 |
| CA242 (U/ml) | 5.42 ± 4.34 | 4.80 ± 3.22 | 5.54 ± 3.31 | 0.996 |
| CA211 (ng/ml) | 1.12 ± 0.84 | 1.49 ± 1.07 | 1.36 ± 1.01 | 0.006 |
| NSE (ng/ml) | 9.58 ± 4.55 | 8.48 ± 4.87 | 9.99 ± 5.32 | 0.793 |
| SCC (ng/ml) | 0.84 ± 0.83 | 1.15 ± 0.78 | 0.93 ± 0.59 | 0.143 |
RCE: routine chest examination; RCRS: respiratory- or cancer-related symptoms; ICD: incidental chest discovery; C/T ratio: consolidation size/tumor size ratio. ∗p value acquired from one-way analysis of variance and Pearson's chi-square tests.