title: Dose effect relationship for late side effects of the rectum and urinary bladder in magnetic resonance image-guided adaptive cervix cancer brachytherapy.
abstract: OBJECTIVE
  To establish dose-response relationships for late side effects of the rectum and bladder in cervix cancer patients after magnetic resonance image-guided adaptive brachytherapy (IGABT).
  
  
  METHODS
  A cohort of 141 patients was treated with 45 to 50.4 Gy with or without cisplatin plus 4 fractions of 7 Gy IGABT. Doses for the most exposed 2, 1, and 0.1-cm(3) (D(2 cc), D(1 cc), D(0.1 cc)) volumes of the rectum and bladder were converted into the equivalent dose in 2 Gy fractions (EQD2), using a linear quadratic model (α/β = 3 Gy). Late side effects were prospectively assessed (using late effects in normal tissues subjective, objective, management and analytic [LENT SOMA]) scales. Dose-response relationships were determined by logit analyses.
  
  
  RESULTS
  Eleven patients developed rectal side effects, and 23 patients had urinary side effects. A significant dose effect was found for all rectal dose-volume histogram (DVH) parameters for patients with side effect grades of 1 to 4 but was only significant for D(2 cc) and D(1 cc) for grades ≥ 2. The ED10 values for D(2 cc) were 73 Gy for grades 1 to 4 and 78 Gy for grades 2 to 4 rectal morbidity. For bladder side effects, a significant dose effect was shown for all DVH parameters for complication grades ≥ 2; the respective ED10 was 101 Gy.
  
  
  CONCLUSIONS
  Well-defined dose-response curves could be established for D(2 cc) in the rectum and the urinary bladder.
authors.affiliation: Department of Radiotherapy, Medical University of Vienna, Vienna, Austria. petra.georg@akhwien.at
authors.forename: Petra
authors.initials: P
authors.lastname: Georg
authors.forename: Richard
authors.initials: R
authors.lastname: Pötter
authors.forename: Dietmar
authors.initials: D
authors.lastname: Georg
authors.forename: Stefan
authors.initials: S
authors.lastname: Lang
authors.forename: Johannes C A
authors.initials: JC
authors.lastname: Dimopoulos
authors.forename: Alina E
authors.initials: AE
authors.lastname: Sturdza
authors.forename: Daniel
authors.initials: D
authors.lastname: Berger
authors.forename: Christian
authors.initials: C
authors.lastname: Kirisits
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Dörr
mesh_terms: D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D002945:Cisplatin / Q000627:therapeutic use; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D016014:Linear Models; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods; D058958:Organs at Risk / Q000528:radiation effects*; D011446:Prospective Studies; D011832:Radiation Injuries / Q000473:pathology*; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D012007:Rectum / Q000528:radiation effects*; D001743:Urinary Bladder / Q000528:radiation effects*; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*
chemical_list: D011838:Radiation-Sensitizing Agents; D002945:Cisplatin