Table 4.
Correlation between factors and RP by univariate analysis
| Factors | Grade ≥ 2 RP (N = 45) | Grade ≥ 3 RP (N = 18) | ||||
|---|---|---|---|---|---|---|
| Grade < 2 RP | Grade ≥ 2 RP | p value | Grade < 3 RP | Grade ≥ 3 RP | p value | |
| Gender | 0.175 | 0.439 | ||||
| Male | 37 | 44 | 63 | 18 | ||
| Female | 5 | 1 | 6 | 0 | ||
| Age (years) | 0.256 | 0.659 | ||||
| < 70 | 25 | 32 | 46 | 11 | ||
| ≥ 70 | 17 | 13 | 23 | 7 | ||
| Smoking history | 0.165 | 0.493 | ||||
| No | 15 | 10 | 21 | 4 | ||
| Yes | 27 | 35 | 48 | 14 | ||
| Pathological type | 0.503 | 0.219 | ||||
| NSCLC | 29 | 28 | 43 | 14 | ||
| SCLC | 13 | 17 | 26 | 4 | ||
| Tumor stage | 0.092 | 0.692 | ||||
| I | 2 | 0 | 2 | 0 | ||
| III | 28 | 36 | 51 | 13 | ||
| IV | 4 | 6 | 7 | 3 | ||
| Postoperative | 8 | 3 | 9 | 2 | ||
| Tumor location | 0.043 | 0.120 | ||||
| Upper lobe | 32 | 25 | 48 | 9 | ||
| Middle or lower lobe | 10 | 20 | 21 | 9 | ||
| Chemotherapy with gemcitabine in the past | 0.856 | 0.031 | ||||
| No | 26 | 27 | 46 | 7 | ||
| Yes | 16 | 18 | 23 | 11 | ||
| Concurrent chemotherapy | 0.142 | 0.782 | ||||
| No | 30 | 38 | 53 | 15 | ||
| Yes | 12 | 7 | 16 | 3 | ||
| Distribution of subclinical ILD | 0.275 | 0.157 | ||||
| Lateral | 7 | 4 | 11 | 0 | ||
| Bilateral | 35 | 41 | 58 | 18 | ||
| Morphology of subclinical ILD | 0.399 | 0.137 | ||||
| No honeycombing | 34 | 33 | 56 | 11 | ||
| Honeycombing | 8 | 12 | 13 | 7 | ||
| Percentage of lung volume affected in subclinical ILD | 0.171 | 0.037 | ||||
| < 25% | 38 | 36 | 62 | 12 | ||
| ≥ 25% | 4 | 9 | 7 | 6 | ||
| Pulmonary emphysema | 0.658 | 0.775 | ||||
| No | 6 | 8 | 12 | 2 | ||
| Yes | 36 | 37 | 57 | 16 | ||
| Total dose (Gy) | 0.834 | 0.349 | ||||
| EQD2 < 60.0 | 13 | 13 | 19 | 7 | ||
| EQD2 ≥ 60.0 | 29 | 32 | 50 | 11 | ||
| Single fraction dose | 0.826 | 1.000 | ||||
| 2.0 Gy | 38 | 39 | 61 | 16 | ||
| > 2.0 Gy, ≤ 3.0 Gy | 4 | 6 | 8 | 2 | ||
| FVC% | 89.53 ± 14.50 | 92.15 ± 25.83 | 0.632 | 89.93 ± 22.58 | 94.53 ± 17.75 | 0.472 |
| FEV1/ FVC (%) | 74.71 ± 9.05 | 74.05 ± 9.89 | 0.782 | 74.57 ± 8.52 | 73.56 ± 12.40 | 0.720 |
| MLD (Gy) | 11.52 ± 3.36 | 12.97 ± 2.45 | 0.024 | 12.00 ± 3.15 | 13.29 ± 2.11 | 0.106 |
| V5 (%) | 46.07 ± 12.51 | 48.24 ± 9.54 | 0.363 | 46.19 ± 11.69 | 51.06 ± 7.25 | 0.097 |
| V10 (%) | 33.14 ± 9.84 | 35.00 ± 7.20 | 0.316 | 33.68 ± 9.26 | 35.72 ± 5.04 | 0.216 |
| V20 (%) | 20.62 ± 6.88 | 21.89 ± 4.46 | 0.314 | 21.10 ± 6.14 | 21.94 ± 4.05 | 0.583 |
| V30 (%) | 14.24 ± 5.64 | 16.07 ± 4.08 | 0.085 | 14.91 ± 5.12 | 16.22 ± 4.22 | 0.321 |
| GTV (cc) | 97.80(3.75–398.99) | 120.17(20.47–497.86) | 0.288 | 105.40(3.75–398.99) | 105.14(20.47–497.86) | 0.991 |
| PTV (cc) | 355.88(69.26–2601.29) | 392.60(300.77–1070.38) | 0.139 | 379.12(69.26–2601.29) | 349.95(257.32–1070.38) | 0.608 |
RP, radiation pneumonitis; NSCLC, non-small-cell lung cancer; SCLC, small-cell lung cancer; ILD, interstitial lung disease; FVC, forced vital capacity; FEV1, forced expiratory volume in one second; FVC%, percentage forced vital capacity; EQD2, equivalent dose in 2.0 Gy/(fraction per day); MLD, mean lung dose; V5, percentage of lung volume receiving ≥ 5 Gy; V10, percentage of lung volume receiving ≥ 10 Gy; V20, percentage of lung volume receiving ≥ 20 Gy; V30, percentage of lung volume receiving ≥ 30 Gy; GTV, gross tumor volume; PTV, planning target volume