title: Modeling Urinary Dysfunction After External Beam Radiation Therapy of the Prostate Using Bladder Dose-Surface Maps: Evidence of Spatially Variable Response of the Bladder Surface.
abstract: We assessed the association of the spatial distribution of dose to the bladder surface, described using dose-surface maps, with the risk of urinary dysfunction.
  
  
  
  The bladder dose-surface maps of 754 participants from the TROG 03.04-RADAR trial were generated from the volumetric data by virtually cutting the bladder at the sagittal slice, intersecting the bladder center-of-mass through to the bladder posterior and projecting the dose information on a 2-dimensional plane. Pixelwise dose comparisons were performed between patients with and without symptoms (dysuria, hematuria, incontinence, and an International Prostate Symptom Score increase of ≥10 [ΔIPSS10]). The results with and without permutation-based multiple-comparison adjustments are reported. The pixelwise multivariate analysis findings (peak-event model for dysuria, hematuria, and ΔIPSS10; event-count model for incontinence), with adjustments for clinical factors, are also reported.
  
  
  
  The associations of the spatially specific dose measures to urinary dysfunction were dependent on the presence of specific symptoms. The doses received by the anteroinferior and, to lesser extent, posterosuperior surface of the bladder had the strongest relationship with the incidence of dysuria, hematuria, and ΔIPSS10, both with and without adjustment for clinical factors. For the doses to the posteroinferior region corresponding to the area of the trigone, the only symptom with significance was incontinence.
  
  
  
  A spatially variable response of the bladder surface to the dose was found for symptoms of urinary dysfunction. Limiting the dose extending anteriorly might help reduce the risk of urinary dysfunction.
authors.affiliation: School of Health Sciences, National University of Malaysia, Kuala Lumpur, Malaysia; School of Physics, University of Western Australia, Perth, Western Australia, Australia. Electronic address: noorazrul.yahya@research.uwa.edu.au.
authors.forename: Noorazrul
authors.initials: N
authors.lastname: Yahya
authors.affiliation: School of Physics, University of Western Australia, Perth, Western Australia, Australia; Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Ebert
authors.affiliation: School of Physics, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: House
authors.affiliation: Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.
authors.forename: Angel
authors.initials: A
authors.lastname: Kennedy
authors.affiliation: Department of Radiation Oncology, Auckland City Hospital, Auckland, New Zealand.
authors.forename: John
authors.initials: J
authors.lastname: Matthews
authors.affiliation: Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; School of Surgery, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Joseph
authors.affiliation: School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: James W
authors.initials: JW
authors.lastname: Denham
mesh_terms: D005500:Follow-Up Studies; D006417:Hematuria / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011829:Radiation Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D063189:Symptom Assessment; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000528:radiation effects*; D014549:Urinary Incontinence / Q000209:etiology / Q000503:physiopathology; D014555:Urination Disorders / Q000209:etiology* / Q000503:physiopathology