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

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.

High-dose thoracic radiation therapy for non-small cell lung cancer: a novel grading scale of radiation-induced lung injury for symptomatic radiation pneumonitis

“…The main novelty of this RGS was based on the hypothesis that higher numbers of lung segments affected by RILI reflect an increased inflammatory response to RT and thus could determine both the severity of RILI and the occurrence of RP. Previous scales used either general terms to describe RILI (Additional file 2: Table A.2) or the percentage of lung volume affected by RILI [25]. The latter is also empirically based, but is more challenging to quantitate from a radiological perspective.…”

“…There are few published reports of inter-observer variability regarding RILI and RP grading scales [25,27], but none regarding the prediction of RP. A study by Yamamoto et al [25] reported a 60% agreement between two observers (Kappa value 0.6).…”

“…There are few published reports of inter-observer variability regarding RILI and RP grading scales [25,27], but none regarding the prediction of RP. A study by Yamamoto et al [25] reported a 60% agreement between two observers (Kappa value 0.6). The current study presents the results of an independent evaluation of radiological images by four senior radiologists and shows a relatively high inter-observer agreement (concordance coefficient 0.8).…”

“…The novel RGS was defined based on prior studies describing the most common radiological findings of lung injury induced by RT [1,[23][24][25]. Typical parenchymal changes and presence of ipsilateral pleural effusion were differentiated into three grades, according to the number of involved lung segments (Table 1).…”

“…Most grading scales focus on the clinical evaluation of RP [19] with a simple description of the radiological signs of toxicity [3,[16][17][18][20][21][22]. Likewise, there are several explicitly descriptive radiological RILI grading scales that do not include a correlation to clinical outcome [1,[22][23][24][25].…”