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Katsui, Kuniaki Department of Proton Beam Therapy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science ORCID Kaken ID
Ogata, Takeshi Department of Radiology, Iwakuni Clinical Center
Watanabe, Kenta Department of Radiology, Okayama University Hospital
Kuroda, Masahiro Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Kaken ID researchmap
Kiura, Katsuyuki Department of Allergy and Respiratory Medicine, Okayama University Hospital Kaken ID researchmap
Hiraki, Takao Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Kaken ID researchmap
Maeda, Yoshinobu Department of Hematology, Oncology, and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Kaken ID researchmap
Toyooka, Shinichi Departments of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science ORCID Kaken ID researchmap
Kanazawa, Susumu Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Kaken ID
Background: Radiation pneumonitis (RP) is a major pulmonary adverse event of chest radiotherapy. The PACIFIC trial that identified durvalumab as an effective subsequent-line therapy after concurrent chemoradiotherapy (CCRT) found that patients with grade 2 or higher RP may have to be excluded from treatment under certain criteria. The purpose of this study was to investigate the relationship between grade ≥2 RP and the parameters of dose-volume histograms after CCRT with cisplatin/docetaxel for stage III non-small cell lung cancer and conduct a subset analysis of severe RP that can lead to the permanent discontinuation of treatment per the PACIFIC trial criteria to help determine treatment strategy.
Methods: We calculated the percentage of the lung volume received at least 5 Gy (V5) and 20 Gy (V20), the mean lung dose (MLD), and the lung volume spared from a 5 Gy dose (VS5) to the total lung volume. Factors affecting the incidence of grade ≥2 RP were identified; severe RP was defined as grade ≥3 as well as grade 2 RP that required ≥10 mg prednisolone for at least 12 weeks.
Results: This study included 45 patients. On univariate analysis, all parameters and total lung volume were found to be significant predictors of grade ≥2 RP (P = .001, .003, .03, .004, and .02, respectively). On multivariate analysis, V20 was a significant predictive factor of grade ≥2 RP (P = .007). Severe RP developed in 6 of 37 patients (16.2%) whose V20 values were 35% or lower. On univariate analysis, only V20 was a significant predictor of severe RP in these patients (P = .01).
Conclusions: The best approach to reduce the rate of grade ≥2 RP is to maintain the V5, V20, MLD, and VS5 as low as possible during radiotherapy planning in patients receiving definitive CCRT with cisplatin/docetaxel.
non-small cell lung cancer
© 2020 The Authors.
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