Impact of Pretreatment Interstitial Lung Disease on Radiation Pneumonitis and Survival in Patients Treated With Lung Stereotactic Body Radiation Therapy (SBRT)

• Published in: Clinical lung cancer 2018-03, Vol.19 (2), p.e219-e226
• Main Authors: Glick, Daniel, Lyen, Stephen, Kandel, Sonja, Shapera, Shane, Le, Lisa W., Lindsay, Patricia, Wong, Olive, Bezjak, Andrea, Brade, Anthony, Cho, B.C. John, Hope, Andrew, Sun, Alexander, Giuliani, Meredith
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Early stage lung cancer; Female; Follow-Up Studies; Humans; Interstitial pneumonia; Lung - physiology; Lung - radiation effects; Lung Diseases, Interstitial; Lung Neoplasms - complications; Lung Neoplasms - epidemiology; Lung Neoplasms - radiotherapy; Lung toxicity; Male; Middle Aged; Prospective Studies; Pulmonary fibrosis; Radiation Pneumonitis - epidemiology; Radiation Pneumonitis - etiology; Radiation Pneumonitis - mortality; Radiosurgery - adverse effects; Risk Factors; SBRT; Survival Analysis; Tomography, X-Ray Computed
• ISSN: 1525-7304; 1938-0690
• DOI: 10.1016/j.cllc.2017.06.021

Interstitial lung disease (ILD) in patients with lung cancer is a management challenge. In this study of 537 patients who underwent lung stereotactic body radiation therapy, we found that patients with ILD (vs. patients without ILD) had greater risk of radiation pneumonitis. On multivariable analysis, ILD and mean lung dose were predictors of radiation pneumonitis. Computed tomography scans should be assessed for ILD before stereotactic body radiation therapy is considered. 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). 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. 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). 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.