Table 2. Logistic regression analysis for radiation pneumonitis ≥ grade 2 (n=85).
| Characteristic | n | Univariate analysis | Multivariate analysis | |||||
|---|---|---|---|---|---|---|---|---|
| HR | 95% CI | P value | HR | 95% CI | P value | |||
| Age | 0.99 | 0.96–1.02 | 0.41 | |||||
| Gender | 0.14 | 0.54 | ||||||
| Male | 408 | 1 | – | – | 1 | – | – | |
| Female | 173 | 1.43 | 0.88–2.31 | – | 0.82 | 0.43–1.54 | – | |
| Pack–years | 0.009 | 0.02 | ||||||
| <20 | 186 | 1.00 | – | – | 1.00 | – | – | |
| 20–50 | 195 | 0.82 | 0.48–1.38 | 0.45 | 0.80 | 0.40–1.56 | 0.51 | |
| >50 | 184 | 0.40 | 0.21–0.73 | 0.003 | 0.36 | 0.16–0.79 | 0.01 | |
| PTV | 1.01 | 1.00–1.01 | 0.049 | 1.00 | 0.99–1.01 | 0.90 | ||
| T stage | 0.02 | 0.047 | ||||||
| T1a–b | 328 | 1 | – | – | 1.00 | – | – | |
| T2a–b | 167 | 1.84 | 1.11–3.04 | 0.02 | 1.30 | 0.68–2.44 | 0.42 | |
| T3–4 | 48 | 0.48 | 0.11–1.40 | 0.20 | 0.30 | 0.06–1.10 | 0.07 | |
| rT1–4 | 38 | 1.92 | 0.78–4.31 | 0.15 | 1.89 | 0.72–4.53 | 0.18 | |
| Histology | 0.34 | |||||||
| Proven NSCLC | 308 | 1 | – | – | – | – | – | |
| Clinical NSCLC | 273 | 1.25 | 0.79–1.99 | – | – | – | – | |
| Location | 0.42 | |||||||
| Peripheral | 411 | 1 | – | – | – | – | – | |
| Central | 170 | 1.22 | 0.74–1.99 | – | – | – | – | |
| %VC | 0.65 | |||||||
| 80–140 | 292 | 1 | – | – | – | – | – | |
| 70–79 | 151 | 1.17 | 0.66–2.02 | 0.59 | – | – | – | |
| −69 + unmeasurable | 138 | 1.30 | 0.73–2.26 | 0.37 | – | – | – | |
| GOLD | 0.07 | 0.39 | ||||||
| Non–COPD | 295 | 1 | – | – | 1 | – | – | |
| I–II | 166 | 0.93 | 0.55–1.55 | 0.89 | 1.28 | 0.71–2.27 | 0.41 | |
| III–IV + unmeasurable | 120 | 0.46 | 0.21–0.90 | 0.02 | 0.75 | 0.32–1.62 | 0.47 | |
| Total dose | 0.10 | 0.11 | ||||||
| 60 Gy | 72 | 0.39 | 0.13–0.93 | 0.03 | 0.38 | 0.12–0.95 | 0.04 | |
| 50 Gy | 401 | 1 | – | – | 1 | – | – | |
| 40 Gy | 108 | 0.92 | 0.49–1.62 | – | 0.93 | 0.47–1.79 | 0.84 | |
| V20 | 1.14 | 1.07–1.23 | 0.001 | 1.14 | 1.02–1.28 | 0.03 | ||
| MLD | – | 1.34 | 1.18–1.52 | 0.001 | – | – | – | |
| Predictable high–risk RP factors | 0.19 | 0.06 | ||||||
| No | 404 | 1 | – | – | 1 | – | – | |
| Yes | 177 | 1.38 | 0.84–2.22 | – | 1.70 | 0.98–2.91 | – | |
| Idiopathic interstitial pneumonias | 0.06 | |||||||
| No | 536 | 1 | – | – | – | – | ||
| Yes | 45 | 2.02 | 0.94–4.05 | – | – | – | – | |
| Elevated KL–6/SP–D | 0.15 | |||||||
| No | 420 | 1 | – | – | – | – | – | |
| Yes | 161 | 1.43 | 0.87–2.32 | – | – | – | – | |
| CAM administration | 0.47 | |||||||
| No | 487 | 1 | – | – | – | – | – | |
| Yes | 94 | 1.24 | 0.67–2.21 | – | – | – | – | |
| Era | 0.047 | 0.04 | ||||||
| Non–CAM era | 445 | 1 | – | – | 1 | – | – | |
| CAM era | 136 | 0.55 | 0.28–0.99 | – | 0.51 | 0.26–0.96 | – | |
HR, hazard ratio; CI, confidence interval; PTV, planning target volume; NSCLC, non-small cell lung cancer; %VC, vital capacity as percent of predicted; GOLD, Global Initiative for Chronic Obstructive Lung Diseases stage; V20, the normal lung volume receiving ≥20 Gy; MLD, mean normal lung dose; RP, radiation pneumonitis; KL-6, sialylated carbohydrate antigen; SP-D, surfactant protein D; CAM, clarithromycin.