Characteristics of the 25 radiotherapy patients
| Characteristics | Presence of RP (n=12) | Absence of RP (n=13) | p‐value |
| Age, yrs | 65.7±12.4 | 64.5±11.2 | ns |
| Male/female | 8/4 | 11/2 | ns |
| Smoker/nonsmoker | 11/1 | 10/3 | ns |
| Histology | |||
| Squamous cell carcinoma | 3 | 10 | |
| Small cell carcinoma | 3 | 0 | |
| Adenocarcinoma | 5 | 3 | |
| Invasive thymoma | 1 | 0 | |
| Preceding anticancer agents | 6 | 3 | ns |
| Total dose, Gy | 56.0±5.4 | 52.7±6.2 | ns |
| New symptom at the completion of RT | 4 | 0 | |
| RP on plain radiography | 3 | 0 | |
| RP on HRCT | 12 | 0 | |
| LDH IU·L−1 | 291.6±83.9 | 283.0±61.8 | ns |
| SP‐A ng·mL−1 | 58.0±17.5 | 37.6±20.8 | 0.0065 |
| SP‐D ng·mL−1 | 145.0±44.3 | 78.6±31.4 | 0.0011 |
| A‐aDO2 mmHg | 22.4±11.4 | 13.9±6.4 | 0.489 |
Values are n or mean±SD
values were obtained 1 week after the completion of radiotherapy
The normal upper limits of SP‐A, SP‐D and LDH were 43.8 ng·mL−1, 112 ng·mL−1 and 440 IU·L−1, respectively
RP: radiation pneumonitis
HRCT: high resolution computed tomography
LDH: lactate dehydrogenase
SP: Surfactant protein
A‐aDO2: alveolar-arterial oxygen diffusion
NS: nonsignificant
Statistical analysis was performed by Fisher's exact probability test and unpaired t‐test.