title: Plan quality and dosimetric association of patient-reported rectal and urinary toxicities for prostate stereotactic body radiotherapy.
abstract: To study the association between dosimetric parameters with patient-reported quality-of-life (QOL) in urinary irritative/incontinency and bowel functions for prostate stereotactic body radiotherapy (SBRT).
  
  
  
  The patient-reported QOL was evaluated using the Expanded Prostate Cancer Index Composite (EPIC-26). According to the progression in QOL score over 12months, patients were assigned to one of three subgroups: score decrement, no change, or increment. The dosimetric parameters were cross-compared among subgroups in urinary and bowel domains using univariate Analysis of Variance (ANOVA). The evaluated dosimetric metrics included target volume, V100 (volume receiving 100% prescription dose); rectal volume/dose-volume endpoints, maximum/mean doses; bladder volume/dose-volume endpoints, and maximum/mean doses.
  
  
  
  Patients with consistent QOL reduction in urinary irritation function were significantly associated with greater mean bladder dose, greater V85/V90/V95/V100 and D2cc/D10cc. Patients with QOL reduction in urinary incontinence were marginally associated with greater mean bladder dose (p=0.06). None of the evaluated dosimetric parameters showed a significant correlation with QOL score change in bowel function.
  
  
  
  Patients with large prostate size were more susceptible to QOL decrements for urinary irritative and incontinency functions. Large bladder V85/V90/V95/V100 was associated with QOL decrements in the urinary irritative domain at 1-year after prostate SBRT.
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA. Electronic address: xqi@mednet.ucla.edu.
authors: X Sharon
authors: XS
authors: Qi
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Jason P
authors: JP
authors: Wang
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Caitlin L
authors: CL
authors: Gomez
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Weber
authors: W
authors: Shao
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Xiaoqing
authors: X
authors: Xu
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Christopher
authors: C
authors: King
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Daniel A
authors: DA
authors: Low
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Michael
authors: M
authors: Steinberg
authors: Department of Radiation Oncology, University of California Los Angeles School of Medicine, USA.
authors: Patrick
authors: P
authors: Kupelian
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003672:Defecation / Q000528:radiation effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011788:Quality of Life; D011832:Radiation Injuries / Q000209:etiology; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000592:standards; D012007:Rectum / Q000528:radiation effects*; D001743:Urinary Bladder / Q000528:radiation effects*; D014549:Urinary Incontinence / Q000209:etiology
keywords: Minimally clinically important difference (MID); Plans quality; Prostate cancer; Quality-of-life (QOL); Stereotactic body radiotherapy (SBRT)