title: Analysis of factors associated with radiation-induced bronchiolitis obliterans organizing pneumonia syndrome after breast-conserving therapy.
abstract: OBJECTIVE
  To evaluate factors associated with radiation-induced bronchiolitis obliterans organizing pneumonia (BOOP) syndrome after breast-conserving therapy.
  
  
  METHODS
  A total of 702 women with breast cancer who received radiotherapy after breast-conserving surgery at seven institutions between July 1995 and December 2006 were analyzed. In all patients, the whole breast was irradiated with two tangential photon beams. The criteria used for the diagnosis of radiation-induced BOOP syndrome were as follows: (1) radiotherapy to the breast within 12 months, (2) general and/or respiratory symptoms lasting for >or=2 weeks, (3) radiographs showing lung infiltration outside the radiation port, and (4) no evidence of a specific cause.
  
  
  RESULTS
  Radiation-induced BOOP syndrome was seen in 16 patients (2.3%). Eleven patients (68.8%) were administered steroids. The duration of steroid administration ranged from 1 week to 3.7 years (median, 1.1 years). Multivariate analysis revealed that age (>or=50 years; odds ratio [OR] 8.88; 95% confidence interval [CI] 1.16-67.76; p = 0.04) and concurrent endocrine therapy (OR 3.05; 95% CI 1.09-8.54; p = 0.03) were significantly associated with BOOP syndrome. Of the 161 patients whose age was >or=50 years and who received concurrent endocrine therapy, 10 (6.2%) developed BOOP syndrome.
  
  
  CONCLUSIONS
  Age (>or=50 years) and concurrent endocrine therapy can promote the development of radiation-induced BOOP syndrome after breast-conserving therapy. Physicians should carefully follow patients who received breast-conserving therapy, especially those who are older than 50 years and received concurrent endocrine therapy during radiotherapy.
authors.affiliation: Department of Radiology, Okayama University Hospital, Okayama, Japan. n-katayama@bea.hi-ho.ne.jp
authors.forename: Norihisa
authors.initials: N
authors.lastname: Katayama
authors.forename: Shuhei
authors.initials: S
authors.lastname: Sato
authors.forename: Kuniaki
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authors.lastname: Katsui
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Takemoto
authors.forename: Toshihide
authors.initials: T
authors.lastname: Tsuda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshida
authors.forename: Tsuneharu
authors.initials: T
authors.lastname: Morito
authors.forename: Tomio
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Akifumi
authors.initials: A
authors.lastname: Mizuta
authors.forename: Takahiro
authors.initials: T
authors.lastname: Waki
authors.forename: Harutaka
authors.initials: H
authors.lastname: Niiya
authors.forename: Susumu
authors.initials: S
authors.lastname: Kanazawa