title: Effect of aging and long-term erectile function after iodine-125 prostate brachytherapy.
abstract: OBJECTIVE
  To evaluate long-term erectile function (EF) in men treated with iodine-125 prostate brachytherapy (PB) and to determine factors predictive for erectile dysfunction (ED), including natural decline because of aging.
  
  
  METHODS
  Two thousand nine hundred twenty-nine patients (implanted July 1989-June 2012) with baseline EF and greater than 10-month followup (FU) are included. About 78.9% had full and 7.9% had partial EF at baseline. EF was assessed on a physician-reported three-point scale. Poisson regression with generalized estimating equations was used to assess predictors of ED and Kaplan-Meier curves time to ED. The effect of aging was calculated from the declining rate of baseline EF seen in sequential 5-year age cohorts and from the Massachusetts Male Aging Study.
  
  
  RESULTS
  The median age was 66 years and median FU 3.5 years (maximum 14 years). About 1142 patients had more than 5 years of FU, and 43% had received 6 months of androgen deprivation therapy (ADT). Significant drop in EF was seen at 6 weeks after PB, with gradual decline thereafter. EF preservation at 5 years for age younger than 55, 56-59, 60-64, 65-69, and 70 year and older was 82%, 73%, 58%, 39%, and 23%, respectively. Comparisons of the 5-year age-related and treatment-related EF decline show that 50% of the long-term EF decline is related to aging. On univariate and multivariate analyses, age at implant, length of FU, hypertension, diabetes, and use of ADT (all p < 0.01) were significant predictors of ED.
  
  
  CONCLUSIONS
  More than 80% of young men have EF preserved 5 years after PB. Age, ADT, history of hypertension, and the natural decline in EF have negative impact on long-term EF after PB.
authors: Vancouver Cancer Center, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada. Electronic address: mkeyes@bccancer.bc.ca.
authors: Mira
authors: M
authors: Keyes
authors: Vancouver Cancer Center, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: Tom
authors: T
authors: Pickles
authors: Cancer Centre for Southern Interior, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: Juanita
authors: J
authors: Crook
authors: Vancouver Cancer Center, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: Michael
authors: M
authors: McKenzie
authors: Fraser Valley Cancer Centre, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: Arthur
authors: A
authors: Cheung
authors: Vancouver Cancer Center, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: Ingrid
authors: I
authors: Spadinger
authors: Vancouver Cancer Center, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: Vincent
authors: V
authors: LaPointe
authors: Cancer Centre for Southern Interior, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: W Francois
authors: WF
authors: Bachand
authors: Vancouver Cancer Center, The British Columbia Provincial Prostate Brachytherapy Program, University of British Columbia, British Columbia Cancer Agency, Canada.
authors: James
authors: J
authors: Morris
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D007172:Erectile Dysfunction / Q000209:etiology*; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010410:Penile Erection / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology*; D012307:Risk Factors
chemical_list: D007457:Iodine Radioisotopes
keywords: Erectile dysfunction; LDR prostate brachytherapy; Male aging; Predictive factors