title: Toxicities of organs at risk in the mediastinal and hilar regions following stereotactic body radiotherapy for centrally located lung tumors.
abstract: BACKGROUND
  We investigated tolerable doses to organs at risk (OARs) in the mediastinum and pulmonary hilum following stereotactic body radiotherapy for centrally located lung tumors.
  
  
  METHODS
  Between 2005 and 2012, 381 patients with lung tumors were treated with stereotactic body radiotherapy of 40 to 60 Gy in five fractions. From among these patients, we extracted those who received greater than 25 Gy irradiation to OARs and analyzed dosimetric factors in relation to grade 3 to 5 toxicities.
  
  
  RESULTS
  In total, 398 OARs in 133 patients were analyzed, with a median follow-up of 33 (range, 3-87) months. The numbers receiving greater than 25 Gy irradiation to the aorta, vena cava, pulmonary artery, pulmonary vein, bronchus, trachea, heart, and esophagus were 72, 33, 73, 60, 55, 13, 69, and 23, respectively. The corresponding median Dmax 0.5 ml were 43.8, 32.0, 32.2, 29.1, 28.4, 28.7, 41.1, and 21.7 Gy. Of these patients, two developed grade 5 and one grade 3 hemoptysis, and two had grade 3 obstructive pneumonia. Two patients with grade 5 hemoptysis received high doses at the pulmonary artery and bronchus (59.2 and 54.4 Gy, and 61.3 and 59.6 Gy, respectively). No other grade 3 to 5 toxicities occurred.
  
  
  CONCLUSIONS
  Therapeutic indications and dose-intensity should be carefully determined for patients with central tumors, especially when doses to the pulmonary artery and bronchus in the pulmonary hilum exceed 50 Gy. Tolerable doses for other OARs might, however, be higher than in this study, though longer follow-up is necessary to assess this possibility.
authors.affiliation: *Radiation Oncology Center, Ofuna Chuo Hospital, Kanagawa, Japan; †Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan; ‡Department of Radiology, Tokai University School of Medicine, Kanagawa, Japan; and §Department of Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Nishimura
authors.forename: Atsuya
authors.initials: A
authors.lastname: Takeda
authors.forename: Naoko
authors.initials: N
authors.lastname: Sanuki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishikura
authors.forename: Yohei
authors.initials: Y
authors.lastname: Oku
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Aoki
authors.forename: Etsuo
authors.initials: E
authors.lastname: Kunieda
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Shigematsu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001980:Bronchi / Q000473:pathology / Q000528:radiation effects; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000601:surgery*; D004947:Esophagus / Q000473:pathology / Q000528:radiation effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008482:Mediastinum / Q000473:pathology / Q000528:radiation effects; D008875:Middle Aged; D058958:Organs at Risk; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000175:diagnosis*; D016634:Radiosurgery / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014132:Trachea / Q000473:pathology / Q000528:radiation effects