Risk factors of radiation pneumonitis in lung cancer

Abstract

7573 Background: The clinical syndrome of radiation pneumonitis develops in 5–15% of patients receiving thoracic radiotherapy for lung cancer. In this study, we evaluated and identified the clinical characteristics, clinical courses of patients who developed radiation pneumonitis compared with patients who did not develop radiation pneumonitis. Methods: One hundred and five lung cancer patients who underwent thoracic radiotherapy between January 2001 and January 2006 were evaluated and clinical characteristics were reviewed retrospectively. Results: The median age of total patients was 60.9 years old and 86 cases (81.9%) of non-small cell lung cancer and 19 cases (18.1%) of small cell lung cancer patients were enrolled. Forty-one cases(39.0%) developed radiation pneumonitis. Among these patients, 23 cases (56.1%) of early radiation pneumonitis, 15 (36.7%) of intermediate and 3 (7.2%) of late were classified by development time. By severity, 10 cases (24.4%) of Grade 1, 23 (56.1%) of Grade 2, 7 (17.1%) of Grade 3 and 1 of Grade 4 radiation pneumonitis were observed. 21cases (51.2%) of patients who developed radiation pneumonitis were treated with corticosteroid for mean duration of 9.8 weeks. Non-smoking history (p=0.046), concomitant other lung disease (p=0.021), and NTCP (Normal Tissue Complication Probability)≥30% (p=0.012) significantly increased risk of radiation pneumonitis development in multivariate analysis. Development of radiation pneumonitis did not affect survival (p=0.456). Conclusions: Radiation pneumonitis was developed in 39% of patients who had received thoracic radiation due to primary lung cancer and 56.1% cases of these radiation pneumonitis patients developed within 2 months. In this study, non-smoking history, concomitant other lung disease and NTCP≥30% were identified as risk factors of radiation pneumonitis, thus, more attention will be needed to these patients group. No significant financial relationships to disclose.