title: Dose to the inferior rectum is strongly associated with patient reported bowel quality of life after radiation therapy for prostate cancer.
abstract: OBJECTIVE
  To evaluate rectal dose and post-treatment patient-reported bowel quality of life (QOL) following radiation therapy for prostate cancer.
  
  
  METHODS
  Patient-reported QOL was measured at baseline and 2-years via the expanded prostate cancer index composite (EPIC) for 90 patients. Linear regression modeling was performed using the baseline score for the QUANTEC normal tissue complication probability model and dose volume histogram (DVH) parameters for the whole and segmented rectum (superior, middle, and inferior).
  
  
  RESULTS
  At 2-years the mean summary score declined from a baseline of 96.0-91.8. The median volume of rectum treated to ≥70 Gy (V70) was 11.7% for the whole rectum and 7.0%, 24.4%, and 1.3% for the inferior, middle, and superior rectum, respectively. Mean dose to the whole and inferior rectum correlated with declines in bowel QOL while dose to the mid and superior rectum did not. Low (V25-V40), intermediate (V50-V60) and high (V70-V80) doses to the inferior rectum influenced bleeding, incontinence, urgency, and overall bowel problems. Only the highest dose (V80) to the mid-rectum correlated with rectal bleeding and overall bowel problems.
  
  
  CONCLUSIONS
  Segmental DVH analysis of the rectum reveals associations between bowel QOL and inferior rectal dose that could significantly influence radiation planning and prognostic models.
authors: University of Michigan Medical Center, Ann Arbor, MI , United States; Veterans Affairs Medical Center, Ann Arbor, MI , United States. Electronic address: stenmark@med.umich.edu.
authors: Matthew H
authors: MH
authors: Stenmark
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Anna S C
authors: AS
authors: Conlon
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Skyler
authors: S
authors: Johnson
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Stephanie
authors: S
authors: Daignault
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Dale
authors: D
authors: Litzenberg
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Robin
authors: R
authors: Marsh
authors: University of Michigan Medical Center, Ann Arbor, MI , United States; Veterans Affairs Medical Center, Ann Arbor, MI , United States.
authors: Timothy
authors: T
authors: Ritter
authors: Henry Ford Medical Center, Detroit, MI , United States.
authors: Sean
authors: S
authors: Vance
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Nayla
authors: N
authors: Kazzi
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Felix Y
authors: FY
authors: Feng
authors: Cedars-Sinai Medical Center, Los Angeles, United States.
authors: Howard
authors: H
authors: Sandler
authors: Emory University, Atlanta, GA, United States.
authors: Martin G
authors: MG
authors: Sanda
authors: University of Michigan Medical Center, Ann Arbor, MI , United States.
authors: Daniel A
authors: DA
authors: Hamstra
mesh_terms: D000368:Aged; D015331:Cohort Studies; D006471:Gastrointestinal Hemorrhage / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011788:Quality of Life; D011832:Radiation Injuries / Q000209:etiology* / Q000503:physiopathology; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012002:Rectal Diseases / Q000209:etiology / Q000503:physiopathology; D012007:Rectum / Q000503:physiopathology / Q000528:radiation effects*
keywords: Patient-reported; Prostate cancer; Quality of life; Radiation