title: Interstitial Lung Change in Pre-radiation Therapy Computed Tomography Is a Risk Factor for Severe Radiation Pneumonitis.
abstract: OBJECTIVE
  We examined clinical and dosimetric factors as predictors of symptomatic radiation pneumonitis (RP) in lung cancer patients and evaluated the relationship between interstitial lung changes in the pre-radiotherapy (RT) computed tomography (CT) and symptomatic RP.
  
  
  METHODS
  Medical records and dose volume histogram data of 60 lung cancer patients from August 2005 to July 2006 were analyzed. All patients were treated with three dimensional (3D) conformal RT of median 56.9 Gy. We assessed the association of symptomatic RP with clinical and dosimetric factors.
  
  
  RESULTS
  With a median follow-up of 15.5 months (range, 6.1 to 40.9 months), Radiation Therapy Oncology Group grade ≥ 2 RP was observed in 14 patients (23.3%). Five patients (8.3%) died from RP. The interstitial changes in the pre-RT chest CT, mean lung dose (MLD), and V30 significantly predicted RP in multivariable analysis (p=0.009, p < 0.001, and p < 0.001, respectively). MLD, V20, V30, and normal tissue complication probability normal tissue complication probability (NTCP) were associated with the RP grade but less so for grade 5 RP. The risk of RP grade ≥ 2, ≥ 3, or ≥ 4 was higher in the patients with interstitial lung change (grade 2, 15.6% to 46.7%, p=0.03; grade 3, 4.4% to 40%, p=0.002; grade 4, 4.4% to 33.3%, p=0.008). Four of the grade 5 RP patients had diffuse interstitial change in pre-RT CT and received chemoradiotherapy.
  
  
  CONCLUSIONS
  Our study identified diffuse interstitial disease as a significant clinical risk for RP, particularly fatal RP. We showed the usefulness of MLD, V20, V30, and NTCP in predicting the incidence and severity of RP.
authors: Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Yun Hee
authors: YH
authors: Lee
authors: Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Yeon Sil
authors: YS
authors: Kim
authors: Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Sang Nam
authors: SN
authors: Lee
authors: Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Hyo Chun
authors: HC
authors: Lee
authors: Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Se Jin
authors: SJ
authors: Oh
authors: Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Seoung Joon
authors: SJ
authors: Kim
authors: Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Young Kyoon
authors: YK
authors: Kim
authors: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Dae Hee
authors: DH
authors: Han
authors: Department of Nuclear Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Ie Ryung
authors: IeR
authors: Yoo
authors: Department of Medical Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Jin Hyung
authors: JH
authors: Kang
authors: Department of Medical Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Suk Hee
authors: SH
authors: Hong
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology* / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D017564:Radiation Pneumonitis / Q000150:complications / Q000000981:diagnostic imaging*; D011874:Radiometry; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
keywords: Interstitial lung diseases; Lung neoplasms; Radiation pneumonitis; Radiotherapy