@article{oai:repo.qst.go.jp:00048372,
 author = {Hayashi, Kazuhiko and Yamamoto, Naoyoshi and Karube, Masataka and Nakajima, Mio and Matsufuji, Naruhiro and Tsuji, Hiroshi and Ogawa, Kazuhiko and Kamada, Tadashi and 林 和彦 and 山本 直敬 and 軽部 雅崇 and 中嶋 美緒 and 松藤 成弘 and 辻 比呂志 and 小川 和彦 and 鎌田 正},
 issue = {1},
 journal = {Radiation Oncology},
 month = {Oct},
 note = {Background
\nCarbon-ion radiotherapy (CIRT) is a promising treatment for locally advanced non-small-cell lung cancer, especially for patients with inoperable lung cancer. Although the incidence of CIRT-induced radiation pneumonitis (RP) ≥ grade 2 ranges from 2.5 to 9.9%, the association between CIRT-induced RP and dosimetric parameters is not clear. Herein, we identified prognostic factors associated with symptomatic RP after CIRT for patients with non-small-cell lung cancer.
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Methods
\nClinical results of 65 patients treated with CIRT between 2000 and 2015 at the National Institute of Radiological Sciences were retrospectively analyzed. Clinical stage II B disease (TNM classification) was the most common stage among the patients (45%). The median radiation dose was 72 Gy (68–76) relative biological effectiveness (RBE) in 16 fractions. In cases involving metastatic lymph nodes, prophylactic irradiation of mediastinal lymph nodes was performed at a median dose of 49.5 Gy (RBE). The median follow-up was 22 months.
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Results
\nGrade 2 and grade 3 RP occurred in 6 and 3 patients (9 and 5%), respectively. No patients developed grade 4 or 5 RP. Using univariate analysis, vital capacity as a percentage of predicted (%VC), forced expiratory volume in 1 s (FEV1), mean lung dose (MLD), volume of lung receiving ≥5 Gy (RBE) (V5), V10, V20 and V30 were determined to be the significant predictive factors for ≥ grade 2 RP. The receiver operating characteristic (ROC) analysis revealed the cutoff values for %VC, FEV1, MLD, V5, V10, V20 and V30 for ≥ grade 2 RP, which were 86.9%, 1.16 L, 12.5 Gy (RBE), 28.8, 29.9, 20.1 and 15.0%, respectively. In addition, the multivariate analysis revealed that %VC <86.9% (odds ratio = 13.7; p = 0.0041) and V30 ≥ 15% (odds ratio = 6.1; p = 0.0221) were significant risk factors.
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Conclusions
\nOur study demonstrated the risk factors for ≥ grade 2 RP after carbon-ion radiotherapy for patients with locally advanced lung cancer.},
 pages = {91-1--91-7},
 title = {Prognostic analysis of radiation pneumonitis: carbon-ion radiotherapy in patients with locally advanced lung cancer},
 volume = {12},
 year = {2017}
}