title: Dosimetric and patient correlates of quality of life after prostate stereotactic ablative radiotherapy.
abstract: OBJECTIVE
  Initial results of Stereotactic Ablative Body Radiotherapy (SABR) in the treatment of localized prostate cancer appear promising however long-term quality of life (QOL) outcomes and dosimetric correlates are necessary.
  
  
  METHODS
  A phase I/II study was performed where low risk prostate cancer patients received SABR 35 Gy in 5 fractions, once weekly. Patient self-reported QOL was measured using the Expanded Prostate Cancer Index Composite (EPIC) at baseline and q6 month up to 5 years. Urinary, bowel and sexual domains were analyzed. A minimally clinical important change (MCIC) was defined as 0.5∗standard deviation of the baseline. Univariate and multivariate logistic regression were used to identify dosimetric predictors of MCIC.
  
  
  RESULTS
  84 patients were included. The median follow-up was 50.8 months (interquartile range [IQR], 44.7-56.3). 17.9%, 26.2% and 37.5% of patients reported worse QOL on follow up in the urinary, bowel and sexual domains respectively. On univariate analysis Rectal V31.8>10%, D1cc>35 Gy were associated with bowel MCIC, penile bulb (PB) V35>4%, V20>40% with sexual MCIC. Of these factors only rectal D1cc and PB V35 were predictors of worse QOL on multivariate analysis.
  
  
  CONCLUSIONS
  Long-term single-institution QOL outcomes are encouraging. Rigorous dosimetric constraints are needed to keep bothersome side effects low.
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Elias
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Joelle
authors.initials: J
authors.lastname: Helou
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada.
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Patrick
authors.initials: P
authors.lastname: Cheung
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Deabreu
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: D'Alimonte
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada.
authors.forename: Perakaa
authors.initials: P
authors.lastname: Sethukavalan
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Mamedov
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada.
authors.forename: Marlene
authors.initials: M
authors.lastname: Cardoso
authors.affiliation: Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada; Department of Radiation Oncology, University of Toronto, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Canada. Electronic address: andrew.loblaw@sunnybrook.ca.
authors.forename: Andrew
authors.initials: A
authors.lastname: Loblaw
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005767:Gastrointestinal Diseases / Q000209:etiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D052801:Male Urogenital Diseases / Q000209:etiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000601:surgery*; D011788:Quality of Life; D011832:Radiation Injuries / Q000209:etiology*; D011874:Radiometry; D016634:Radiosurgery / Q000009:adverse effects*; D057566:Self Report; D012735:Sexual Dysfunction, Physiological / Q000209:etiology*
chemical_list: D017430:Prostate-Specific Antigen
keywords: Image-guided radiotherapy; Prostate cancer; Quality of life; Stereotactic Ablative Body Radiotherapy