title: Tadalafil for prevention of erectile dysfunction after radiotherapy for prostate cancer: the Radiation Therapy Oncology Group [0831] randomized clinical trial.
abstract: OBJECTIVE
  Tadalafil is used to treat erectile dysfunction after prostate cancer treatment, but its role as a preventive agent is undefined.
  
  
  OBJECTIVE
  To determine primarily whether tadalafil preserved erectile function in men treated with radiotherapy for prostate cancer, and secondarily to determine whether participant- or partner-reported overall sexual function and sexual and marital satisfaction were affected.
  
  
  METHODS
  Stratified, placebo-controlled, double-blind, parallel-group study with 1:1 randomization at 76 community-based and tertiary medical sites in the United States and Canada. Two hundred forty-two participants with intact erectile function scheduled to receive radiotherapy for prostate cancer were recruited between November 2009 and February 2012 with follow-up through March 2013.
  
  
  METHODS
  One hundred twenty-one participants were assigned 5 mg of tadalafil daily and 121 were assigned placebo for 24 weeks starting with external radiotherapy (63%) or brachytherapy (37%). Participant-reported International Index of Erectile Function response before radiotherapy and at weeks 2 and 4, between weeks 20 and 24, between weeks 28 and 30, and 1 year thereafter. Participants and partners could respond also to the Sexual Adjustment Questionnaire and to the Locke Marital Adjustment Test before radiotherapy, between weeks 20 and 24 and weeks 28 and 30, and at 1 year.
  
  
  METHODS
  Primary outcome was off-drug spontaneous erectile function 28 to 30 weeks after radiotherapy started. Secondary end points were spontaneous erection at 1 year; overall sexual function and satisfaction; marital adjustment; and partner-reported satisfaction and marital adjustment at 28 to 30 weeks and 1 year, predictors of tadalafil response; and adverse events.
  
  
  RESULTS
  Among 221 evaluable participants, 80 (79%; 95% CI, 70%-88%) assigned to receive tadalafil retained erectile function between weeks 28 and 30 compared with 61 (74%; 95% CI, 63%-85%) assigned to receive placebo (P = .49); an absolute difference of 5% (95% CI, -9% to 19%). A significant difference was also not observed at 1 year (72%; 95% CI, 60%-84% vs 71%; 95% CI, 59%-84%; P = .93). Tadalafil was not associated with significantly improved overall sexual function or satisfaction; a significant difference was not observed in any domain subscale. Partners of men assigned tadalafil noted no significant effect on sexual satisfaction, and marital adjustment was not significantly improved in participants or partners.
  
  
  CONCLUSIONS
  Among men undergoing radiotherapy for prostate cancer, daily use of tadalafil compared with placebo did not result in improved erectile function. These findings do not support daily use of tadalafil to prevent erectile dysfunction in these patients.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00931528.
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Pisansky
authors.affiliation: Radiation Therapy Oncology Group, Philadelphia, Pennsylvania.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Pugh
authors.affiliation: Fox Chase Cancer Center, Philadelphia, Pennsylvania.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Greenberg
authors.affiliation: Cross Cancer Institute, Edmonton, Alberta.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Pervez
authors.affiliation: Arizona Center for Cancer Care, Phoenix.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Reed
authors.affiliation: Sutter Medical Group, Sacramento, California.
authors.forename: Seth A
authors.initials: SA
authors.lastname: Rosenthal
authors.affiliation: Toledo Community Hospital Community Clinical Oncology Program, Toledo, Ohio.
authors.forename: Rex B
authors.initials: RB
authors.lastname: Mowat
authors.affiliation: Christiana Care Health Service Community Clinical Oncology Program, Newark, Delaware.
authors.forename: Adam
authors.initials: A
authors.lastname: Raben
authors.affiliation: Stanford University, Stanford, California.
authors.forename: Mark K
authors.initials: MK
authors.lastname: Buyyounouski
authors.affiliation: Boston Medical Center Minority-Based Community Clinical Oncology Program, Boston, Massachusetts.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Kachnic
authors.affiliation: Emory University, Atlanta, Georgia.
authors.forename: Deborah W
authors.initials: DW
authors.lastname: Bruner
mesh_terms: D000223:Adaptation, Psychological; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy; D002243:Carbolines / Q000627:therapeutic use*; D004311:Double-Blind Method; D007172:Erectile Dysfunction / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008393:Marriage; D008875:Middle Aged; D017060:Patient Satisfaction; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000517:prevention & control*; D012725:Sexual Behavior; D000068581:Tadalafil; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D002243:Carbolines; D014665:Vasodilator Agents; D000068581:Tadalafil