title: Randomized, double-blinded, placebo-controlled crossover trial of treating erectile dysfunction with sildenafil after radiotherapy and short-term androgen deprivation therapy: results of RTOG 0215.
abstract: BACKGROUND
  Erectile dysfunction (ED) may be the most commonly observed adverse event (AE) associated with the combination of radiation therapy (RT) and androgen deprivation therapy (ADT). A significant number of men are trying phosphodiesterase type 5 inhibitors (PDE5s) such as sildenafil to treat ED, yet sildenafil studies to date shed little light on the response to ED after ADT.
  
  
  OBJECTIVE
  The purpose of this trial was to evaluate sildenafil in the treatment of ED in prostate cancer patients previously treated with external beam RT and neoadjuvant and concurrent ADT.
  
  
  METHODS
  In this randomized, double-blinded crossover trial, eligible patients received RT/ADT for intermediate risk prostate cancer and currently had ED as defined by the International Index of Erectile Function (IIEF). Patients were randomized to 12 weeks of sildenafil or placebo followed by 1 week of no treatment then 12 weeks of the alternative. Treatment differences were evaluated using a marginal model for binary crossover data.
  
  
  METHODS
  The primary end point was improved erectile function, as measured by the IIEF.
  
  
  RESULTS
  The study accrued 115 patients and 61 (55%) completed all three IIEF assessments. Sildenafil effect was significant (P = 0.009) with a difference in probabilities of erectile response of 0.17 (95% confidence interval: 0.06, 0.29), and 0.21 (0.06, 0.38) for patients receiving ≤ 120 days of ADT. However, as few as 21% of patients had a treatment-specific response, only improving during sildenafil but not during the placebo phase.
  
  
  CONCLUSIONS
  This is the first controlled trial to suggest a positive sildenafil response for ED treatment in patients previously treated with RT/ADT, however, only a minority of patients responded to treatment. ADT duration may be associated with response and requires further study. The overall low response rate suggests the need for study of additional or preventative strategies for ED after RT/ADT for prostate cancer.
authors.affiliation: University of Pennsylvania, Philadelphia, Pennsylvania, USA. wbruner@nursing.upenn.edu
authors.forename: Deborah
authors.initials: D
authors.lastname: Watkins Bruner
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: James
authors.forename: Charlene J
authors.initials: CJ
authors.lastname: Bryan
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Pisansky
authors.forename: Marvin
authors.initials: M
authors.lastname: Rotman
authors.forename: Thomas
authors.initials: T
authors.lastname: Corbett
authors.forename: Joycelyn
authors.initials: J
authors.lastname: Speight
authors.forename: Roger
authors.initials: R
authors.lastname: Byhardt
authors.forename: Howard
authors.initials: H
authors.lastname: Sandler
authors.forename: Søren
authors.initials: S
authors.lastname: Bentzen
authors.forename: Lisa
authors.initials: L
authors.lastname: Kachnic
authors.forename: Lawrence
authors.initials: L
authors.lastname: Berk
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000728:Androgens; D006801:Humans; D018783:Impotence, Vasculogenic / Q000188:drug therapy* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000150:complications / Q000188:drug therapy* / Q000532:radiotherapy; D011687:Purines / Q000627:therapeutic use; D011878:Radiotherapy / Q000009:adverse effects*; D018570:Risk Assessment; D057566:Self Report; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*
chemical_list: D000728:Androgens; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate