Table 2.
Details of radiation therapy and univariate analysis
| Variable | All cases(n = 38) | Radiation pneumonitis |
Univariate analysis |
||
|---|---|---|---|---|---|
| Grade 0-1(n = 29) | Grade 2+(n = 9) | OR(95% CI) | P value | ||
| Treatment period, mean (range), d | 8 (4-15) | 8 (4-15) | 8 (4-10) | 0.99 (0.76-1.28) |
.93 |
| Prescribed dose at periphery | |||||
| 42-50 Gy in 4 fractions | 29 | 22 | 7 | 0.90 (0.12-4.86) |
.91 |
| Other fractionations | 9 | 7 | 2 | ||
| Timing of irradiation of the multiple PTVs | |||||
| Concurrently | 22 | 16 | 6 | 1.63 (0.35-8.90) |
.54 |
| Sequentially or alternately | 16 | 13 | 3 | ||
| Summed PTV, mean (range), cm3 | 63.6 (16.2-179.0) |
61.8 (16.2-179.0) |
69.3 (25.9-111.3) |
1.00 (0.99-1.02) |
.66 |
| MLD, mean (range), Gy | 6.0 (2.6-11.2) |
5.6 (2.8-10.5) |
7.5 (2.6-11.2) |
1.59 (1.09-2.50) |
.023 |
| Lung V5Gy, mean (range), % | 30.6 (12.1-54.2) |
28.0 (14.7-45.5) |
39.1 (12.1-54.2) |
1.13 (1.04-1.27) |
.012 |
| Lung V20Gy, mean (range), % | 8.4 (2.0-19.0) |
7.6 (2.0-19.0) |
11.0 (4.9-18.9) |
1.18 (1.00-1.43) |
.052 |
Abbreviations: CI = confidence interval; lung VxGy = the volume of the normal lung receiving ≥x Gy; MLD = mean lung dose; OR = odds ratio; PTV = planning target volume.