Exclusion of emphysematous lung from dose-volume estimates of risk improves prediction of radiation pneumonitis
- PDF / 2,088,593 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 1 Downloads / 157 Views
RESEARCH
Open Access
Exclusion of emphysematous lung from dose-volume estimates of risk improves prediction of radiation pneumonitis Yasuki Uchida1, Takuya Tsugawa2, Sachiko Tanaka-Mizuno3,4, Kazuo Noma5, Ken Aoki2, Wataru Shigemori1, Hiroaki Nakagawa1, Daisuke Kinose1, Masafumi Yamaguchi1, Makoto Osawa1,6, Emiko Ogawa1,7 and Yasutaka Nakano1*
Abstract Background: The risk factors for radiation pneumonitis (RP) in patients with chronic obstructive pulmonary disease (COPD) are unclear. Mean lung dose (MLD) and percentage of irradiated lung volume are common predictors of RP, but the most accurate dosimetric parameter has not been established. We hypothesized that the total lung volume irradiated without emphysema would influence the onset of RP. Methods: We retrospectively evaluated 100 patients who received radiotherapy for lung cancer. RP was graded according to the Common Terminology Criteria for Adverse Events (version 4.03). We quantified low attenuation volume (LAV) using quantitative computed tomography analysis. The association between RP and traditional dosimetric parameters including MLD, volume of the lung receiving a dose of ≥2 Gy, ≥ 5 Gy, ≥ 10 Gy, ≥ 20 Gy, and ≥30 Gy, and counterpart measurements of the lung without LAV, were analyzed by logistic regression. We compared each dosimetric parameter for RP using multiple predictive performance measures including area under the receiver operating characteristic curve (AUC) and integrated discrimination improvement (IDI). Results: Of 100 patients, RP of Grades 1, 2, 3, 4, and 5 was diagnosed in 24, 12, 13, 1, and 1 patients, respectively. Compared with traditional dosimetric parameters, counterpart measurements without LAV improved risk prediction of symptomatic RP. The ratio of the lung without LAV receiving ≥30 Gy to the total lung volume without LAV most accurately predicted symptomatic RP (AUC, 0.894; IDI, 0.064). Conclusion: Irradiated lung volume without LAV predicted RP more accurately than traditional dosimetric parameters. Keywords: Radiation pneumonitis, Chronic obstructive pulmonary disease, Low attenuation volume, Dosimetric parameter, Lung cancer
Background Smoking is a major cause of both lung cancer and chronic obstructive pulmonary disease (COPD). Whether emphysematous lesion is a risk factor for radiation pneumonitis (RP) after radiotherapy (RT) is an important clinical problem, but the results obtained so far have been controversial. Some studies showed that COPD is a risk factor for RP [1–4], while others reported that RP was milder in patients * Correspondence: [email protected] 1 Division of Respiratory Medicine, Department of Internal Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan Full list of author information is available at the end of the article
with more severe COPD than in patients with normal lung function [5, 6]. There was also a report that COPD does not influence RP [7]. In that study, a scoring system similar to the modified Goddard system was used to evaluate the association between RP and
Data Loading...
