Table 2. Patients demographics and associations with the risk of developing ≥ 2 RP (n = 265).
| Univariate analysis | Multivariate analysis | ||||||
|---|---|---|---|---|---|---|---|
| Parameters | No. of patients (%) | HR | 95% CI | P value | HR | 95% CI | P valuea |
| Age, years | |||||||
| >65 | 127(47.9) | 1 | 1 | ||||
| ≤65 | 138(52.1) | 1.02 | 0.557–1.869 | 0.949 | 0.824 | 0.402–1.691 | 0.598 |
| Gender | |||||||
| male | 207(78.1) | 1 | 1 | ||||
| female | 58(21.9) | 0.588 | 0.248–1.395 | 0.228 | 0.615 | 0.225–1.671 | 0.341 |
| Smoking | |||||||
| never | 110(41.5) | 1 | 1 | ||||
| CSI≤600 | 81(30.6) | 0.712 | 0.352–1.140 | 0.344 | 1.158 | 0.522–2.569 | 0.719 |
| CSI>600 | 74(27.9) | 0.660 | 0.303–1.436 | 0.295 | 0.664 | 0.287–1.536 | 0.339 |
| Pulmonary emphysema | |||||||
| No | 184(69.4) | 1 | 1 | ||||
| Yes | 81(30.6) | 0.790 | 0.397–1.572 | 0.502 | 0.725 | 0.348–1.509 | 0.390 |
| Diabetes | |||||||
| No | 247(93.2) | 1 | 1 | ||||
| Yes | 18(6.8) | 0.314 | 0.043–2.284 | 0.253 | 0.422 | 0.056–3.211 | 0.405 |
| Hypertension | |||||||
| No | 205(77.4) | 1 | 1 | ||||
| Yes | 60(22.6) | 0.663 | 0.294–1.492 | 0.321 | 0.830 | 0.360–1.916 | 0.663 |
| KPS | |||||||
| >80 | 117(44.2) | 1 | 1 | ||||
| ≤80 | 148(55.8) | 1.320 | 0.708–2.460 | 0.383 | 1.412 | 0.731–2.728 | 0.305 |
| Tumor location | |||||||
| Cervical+ Upper thoracic | 106(40.0) | 1 | 1 | ||||
| Middle thoracic | 120(45.3) | 0.637 | 0.294–1.381 | 0.253 | 0.689 | 0.301–1.574 | 0.376 |
| Lower thoracic | 39(14.7) | 0.438 | 0.195–0.987 | 0.046 | 0.470 | 0.200–1.104 | 0.083 |
| Stage | |||||||
| II | 58(21.9) | 1 | 1 | ||||
| III | 185(69.8) | 0.303 | 0.102–0.901 | 0.032 | 0.400 | 0.125–1.281 | 0.123 |
| IV | 22(8.3) | 0.459 | 0.201–1.048 | 0.065 | 0.711 | 0.286–1.769 | 0.463 |
| Chemotherapy | |||||||
| No | 74(27.9) | 1 | 1 | ||||
| Yes | 191(72.1) | 2.434 | 1.026–5.778 | 0.044 | 2.190 | 0.843–5.688 | 0.107 |
| Radiotherapy | |||||||
| CRT | 120(45.3) | 1 | 1 | ||||
| IMRT | 145(54.7) | 0.615 | 0.334–1.134 | 0.119 | 0.708 | 0.367–1.366 | 0.303 |
| Radiation dose, Gy | |||||||
| >55.7 | 191(72.1) | 1 | 1 | ||||
| ≤55.7 | 74(27.9) | 0.491 | 0.218–1.107 | 0.086 | 0.557 | 0.240–1.294 | 0.173 |
| MLDb, Gy | |||||||
| >11.6 | 126(47.5) | 1 | 1 | ||||
| ≤11.6 | 139(52.5) | 0.186 | 0.086–0.403 | <0.001 | 0.205 | 0.092–0.455 | <0.001 |
| V20b, % | |||||||
| >17.1 | 154(58.1) | 1 | 1 | ||||
| ≤17.1 | 111(41.9) | 0.253 | 0.112–0.570 | 0.001 | 0.261 | 0.115–0.594 | 0.001 |
a Multivariate analyses were adjusted for all of the factors in this table.
b Either MLD or V20 was used in multivariate analyses, but not together.
Abbreviations: CSI, cigarette smoking index; KPS, Kamofsky performance status; CRT, conformal radiation therapy; IMRT, intensity-modulated radiation therapy; MLD, mean lung dose; V20, volume of normal lungs receiving 20 Gy or more radiation.