title: Dose-response relations for stricture in the proximal oesophagus from head and neck radiotherapy.
abstract: OBJECTIVE
  Determination of the dose-response relations for oesophageal stricture after radiotherapy of the head and neck.
  
  
  METHODS
  In this study 33 patients who developed oesophageal stricture and 39 patients as controls are included. The patients received radiation therapy for head and neck cancer at Karolinska University Hospital, Stockholm, Sweden. For each patient the 3D dose distribution delivered to the upper 5 cm of the oesophagus was analysed. The analysis was conducted for two periods, 1992-2000 and 2001-2005, due to the different irradiation techniques used. The fitting has been done using the relative seriality model.
  
  
  RESULTS
  For the treatment period 1992-2005, the mean doses were 49.8 and 33.4 Gy, respectively, for the cases and the controls. For the period 1992-2000, the mean doses for the cases and the controls were 49.9 and 45.9 Gy and for the period 2001-2005 were 49.8 and 21.4 Gy. For the period 2001-2005 the best estimates of the dose-response parameters are D(50)=61.5 Gy (52.9-84.9 Gy), γ=1.4 (0.8-2.6) and s=0.1 (0.01-0.3).
  
  
  CONCLUSIONS
  Radiation-induced strictures were found to have a dose response relation and volume dependence (low relative seriality) for the treatment period 2001-2005. However, no dose response relation was found for the complete material.
authors.affiliation: Department of Oncology-Pathology, Division of Medical Radiation Physics, Karolinska Institutet and Stockholm University, Stockholm, Sweden. Eleftheria.Alevronta@ki.se
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Alevronta
authors.forename: Alexander
authors.initials: A
authors.lastname: Ahlberg
authors.forename: Panayiotis
authors.initials: P
authors.lastname: Mavroidis
authors.forename: Massoud
authors.initials: M
authors.lastname: al-Abany
authors.forename: Signe
authors.initials: S
authors.lastname: Friesland
authors.forename: Aris
authors.initials: A
authors.lastname: Tilikidis
authors.forename: Göran
authors.initials: G
authors.lastname: Laurell
authors.forename: Bengt K
authors.initials: BK
authors.lastname: Lind
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D004307:Dose-Response Relationship, Radiation; D004940:Esophageal Stenosis / Q000453:epidemiology / Q000209:etiology*; D004947:Esophagus / Q000528:radiation effects*; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000453:epidemiology; D011878:Radiotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D013548:Sweden / Q000453:epidemiology