Prediction of radiation pneumonitis following high-dose thoracic radiation therapy by 3 Gy/fraction for non-small cell lung cancer: analysis of clinical and dosimetric factors.
OBJECTIVE
This study was undertaken to identify the factors predictive of radiation pneumonitis (RP) in 69 non-small cell lung cancer patients treated with thoracic radiation therapy only by 3 Gy fractions.


METHODS
A total of 69 patients who received only RT in daily 3 Gy were included in this study. Grade > or =3 RP was defined as an RP event. The cumulative incidence of RP was estimated and the correlations of the development of RP with the potential predictors were determined.


RESULTS
The cumulative incidence of events was 17.1% at 12 months. By univariate analysis, all clinical factors [age, performance status, weight loss, pre-RT forced expiratory volume in 1 s, tumour location, stage, RT dose and clinical target volume] were not associated with the risk of Grade > or =3 RP; however, all dosimetric factors [V5-50 and mean lung dose (MLD)] closely correlated with the development of RP. The receiver-operative characteristics (ROC) analysis revealed that MLD was the best predictors of Grade > or =3 RP (area under curve ROC = 0.937). By multivariate analysis, MLD was the only significant factor to be predictive of RP risk: the probability of Grade > or =3 RP was 3.7% when MLD < or = 16.1 Gy and 78.4% when MLD > 16.1 Gy.


CONCLUSIONS
Dosimetric parameters were valuable in predicting the development of RP.
Oh
Dongryul
D
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, Republic of Korea.
Ahn
Yong Chan
YC
Park
Hee Chul
HC
Lim
Do Hoon
DH
Han
Youngyih
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011014:Pneumonia / Q000209:etiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D011878:Radiotherapy / Q000009:adverse effects; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors