Table 2. Univariate analysis with Cox proportional hazard model for disease-free survival.
| Variables | Hazard ratio (95% CI) | P value |
|---|---|---|
| Age (years) | 0.994 (0.945–1.045) | 0.807 |
| Female sex | 1.711 (0.791–3.701) | 0.172 |
| Pleural invasion | 3.389 (1.360–8.449) | 0.009 |
| Lymphatic invasion | 1.995 (0.885–4.500) | 0.096 |
| Vascular invasion | 2.319 (0.869–6.188) | 0.093 |
| SUVmax on FDG-PET | 1.495 (0.763–2.930) | 0.242 |
| CEA | 1.077 (0.728–1.593) | 0.712 |
| EGFR mutation | 2.313 (1.068–5.011) | 0.034 |
| GGO | 1.931 (0.886–4.209) | 0.098 |
| 2DS | 1.292 (0.826–2.020) | 0.262 |
| 3DV* | 1.585 (0.986–2.548) | 0.057 |
| 3DSV** | 2.295 (1.307–4.028) | 0.004 |
| 3DSV/3DV (%) | 1.055 (1.010–1.012) | 0.016 |
*, converted diameter derived from 3DV; **, converted diameter derived from 3DSV. CI, confidence interval; SUVmax, maximum standard uptake value; FDG-PET, [18F] fluorodeoxyglucose positron emission tomography; CEA, carcinoembryonic antigen; EGFR, epidermal growth factor receptor; GGO, ground-glass opacity; 2DS, tumor size on the two-dimensional axial image; 3DV, three-dimensional tumor volume between –600 and 199 HU; 3DSV, three-dimensional solid volume between 0 and 199 HU.