Assessment and agreement of the CT appearance pattern and its severity grading of radiation-induced lung injury after stereotactic body radiotherapy for lung cancer.

Takaya Yamamoto,Noriyoshi Takahashi,Rei Umezawa,Haruo Matsushita,Yu Katagiri,Noriyuki Kadoya,Yoshinao Sato,Yohei Morishita,Ken Takeda,Yojiro Ishikawa,Keiichi Jingu,Aamir Ahmad

doi:10.1371/journal.pone.0204734

Takaya Yamamoto, Noriyoshi Takahashi + Show 10 more

Open Access

https://doi.org/10.1371/journal.pone.0204734

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Journal: PloS one	Publication Date: Oct 4, 2018
Citations: 6	License type: CC BY 4.0

Affiliation: Tohoku University

Abstract

PurposeRadiographic severity of radiation-induced lung injury (RILI) has not been well-studied. The goal of this study was to assess the CT appearance pattern and severity of RILI without consideration of the clinical presentation.Material and methodsA total of 49 patients, 41 with primary lung cancer and 8 with metastatic lung cancer, were treated by 4-fraction stereotactic body radiotherapy (SBRT). RILI after SBRT was separately assessed by two observers. The early and late CT appearance patterns and CT-based severity grading were explored.ResultsThe median follow-up period was 39.0 months. In the early CT findings of observers 1 and 2, there was diffuse consolidation in 15 and 8, diffuse ground glass opacity (GGO) in 0 and 0, patchy consolidation and GGO in 17 and 20, patchy GGO in 3 and 3, and no changes in 10 and 14, respectively (kappa = 0.61). In late CT findings of observer 1 and 2, there were modified conventional pattern in 28 and 24, mass-like pattern in 8 and 11, scar-like pattern in 12 and 12, and no changes in 1 and 2, respectively (kappa = 0.63). In the results of the CT-based grading by observers 1 and 2, there were grade 0 in 1 and 2, grade 1 in 10 and 14, grade 2 in 31 and 29, grade 3 in 7 and 4, and none of grade 4 or more, respectively (kappa = 0.66). According to multivariate analyses (MVA), the significant predicting factors of grade 2 or more CT-based RILI were age (p = 0.01), oxygen dependence (p = 0.03) and interstitial shadow (p = 0.03).ConclusionsThe agreement of the CT appearance and CT-based grading between two observers was good. These indicators may be able to provide us with more objective information and a better understanding of RILI.

Highlights

Stereotactic body radiotherapy (SBRT) for lung cancer is performed worldwide [1,2,3]
The agreement of the CT appearance and CT-based grading between two observers was good. These indicators may be able to provide us with more objective information and a better understanding of Radiation-induced lung injury (RILI)
Common Terminology Criteria for Adverse Events (CTCAE) grading of pulmonary fibrosis includes radiographic pulmonary fibrosis, it is not appropriate for RILI after SBRT considering the CT appearance pattern after SBRT

Summary

Introduction

Stereotactic body radiotherapy (SBRT) for lung cancer is performed worldwide [1,2,3]. CTCAE grading of pneumonitis deals with the symptomatic and therapeutic factors for RILI, but cannot assess the radiographic severity. Many doctors have difficulty assessing RILI of oxygendependent patients treated with home oxygen therapy (HOT) because they frequently develop dyspnea and require an increase of oxygen flow in spite of a moderate radiographic change. These symptoms can be caused by RILI and by progression of their underlying disease and poor pulmonary preservation. One radiologist and one radiation oncologist separately assessed early and late CT appearances and graded late RILI using a CT-based severity grading scale after SBRT. The predictive factors of CT-based RILI grading were explored

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Conclusion