Clin Lung Cancer 2017 Jul 10
Impact of Pretreatment Interstitial Lung Disease on Radiation Pneumonitis and Survival in Patients Treated With Lung Stereotactic Body Radiation Therapy (SBRT).
Abstract
Introduction
The purpose of this study was to determine the impact of interstitial lung disease (ILD) on radiation pneumonitis (RP) and overall survival (OS) in lung stereotactic body radiation therapy (SBRT).
Methods
Patients treated with lung SBRT from 2004 to 2015 were included. Pretreatment computed tomography scans were reviewed and classified for interstitial changes by thoracic radiologists using American Thoracic Society guidelines and Washko and Kazerooni scores. RP was scored prospectively using Common Terminology Criteria for Adverse Events, version 3.0. Pretreatment imaging characteristics, clinical variables, and dosimetry were assessed by univariate (UVA) and multivariate analysis (MVA). OS was assessed by the log-rank test, and the impact of ILD on OS was assessed by Cox regression.
Results
Of the 537 patients assessed, 39 had interstitial changes (13 usual interstitial pneumonia [UIP], 24 possible UIP, and 2 inconsistent with UIP). RP was significantly higher in patients with ILD than in patients without ILD (grade ≥ 2, 20.5% vs. 5.8%; P < .01; grade ≥ 3, 10.3% vs. 1.0%; P < .01). Two of 3 grade 5 RP had imaging features of ILD. On UVA, ILD, Washko score, lung parameters performance status, and dose were significant predictors of grade ≥ 2 RP. On MVA, ILD (odds ratio, 5.81; 95% confidence interval, 2.28-14.83; P < .01) and mean lung dose (odds ratio, 1.40; 95% confidence interval, 1.14-1.71; P < .01) were predictors of RP. ILD did not significantly affect OS on UVA or MVA. Median survival was 27.4 months in the ILD cohort and 34.8 in the ILD-negative cohort (P = .17).
Discussion
ILD is a significant risk factor for RP in patients treated with lung SBRT. Computed tomography scans should be reviewed for evidence of ILD prior to SBRT.
Related Questions
How does the presence of interstitial lung disease affect your decision to offer SBRT for early stage NSCLC?
As opposed to interstitial lung disease (ILD) in general, the entity most described in the literature as associated with severe pulmonary toxicity after SABR has more specifically been idiopathic pulmonary fibrosis (IPF) and additionally, in the absence of a known diagnosis of IPF, CT findings consi...
Do you use minimum cutoff values for any PFTs below which you would not offer conventionally fractionated chemoradiation or SBRT for NSCLC?
We have historically not used a cut-off lower-limit for FEV1 or DLCO when selecting patients for SBRT for stage I NSCLC. This is supported by both our own (PMID 19487961) and the Indiana University (PMID 18394819) series in which patients were divided into quartiles by baseline PFT's. In both series...