Impact of pretreatment interstitial lung disease on radiation pneumonitis and survival after stereotactic body radiation therapy for lung cancer.
BACKGROUND
To investigate the impact of pre-existing radiological interstitial lung disease (ILD) findings on the incidence of radiation pneumonitis (RP) and clinical outcomes after stereotactic body radiation therapy (SBRT) for stage I non-small-cell lung cancer.


METHODS
We included 157 consecutive patients who underwent SBRT alone for stage I non-small-cell lung cancer and whose pretreatment lung computed tomography images were available for retrospective review. The pretreatment computed tomography images were evaluated retrospectively for the presence of ILD. The incidence of RP, overall survival (OS) rate, and the incidence of disease progression and local progression were evaluated between patients with ILD (ILD[+]) and without ILD (ILD[-]).


RESULTS
Pre-existing ILD was identified in 20 patients. The median follow-up period was 39.5 months. The incidences of RP worse than grade 2 (≥ Gr2 RP) and worse than grade 3 (≥ Gr3 RP) were significantly higher in ILD(+) than ILD(-) (1 year ≥ Gr2 RP rate, 55.0% versus 13.3%; p < 0.001 and 1year ≥ Gr3 RP rate 10.0% versus 1.5%; p = 0.020). Multivariate analysis also indicated that ILD(+) was a risk factor for ≥ Gr2 and ≥ Gr3 RP, and the volume of the irradiated lung. The OS rate tended to be worse in ILD(+) than ILD(-) (3-year OS, 53.8% versus 70.8%; p = 0.28). No difference was observed in the disease progression or local progression rates.


CONCLUSIONS
Pre-existing ILD was a significant risk factor for symptomatic and severe RP. Prescreening for ILD findings is important for determining the radiation pneumonitis risk when planning SBRT.
*Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto, Japan; †Department of Genome Biology, Kinki University Faculty of Medicine, Osaka-Sayama, Japan; ‡Departments of Respiratory Medicine, and §Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; and ‖Department of Therapeutic Radiology, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Nami
N
Ueki
Yukinori
Y
Matsuo
Yosuke
Y
Togashi
Takeshi
T
Kubo
Keiko
K
Shibuya
Yusuke
Y
Iizuka
Takashi
T
Mizowaki
Kaori
K
Togashi
Michiaki
M
Mishima
Masahiro
M
Hiraoka
D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D017564:Radiation Pneumonitis / Q000503:physiopathology*; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome