title: Time of decline in sexual function after external beam radiotherapy for prostate cancer.
abstract: OBJECTIVE
  Erectile dysfunction is one of the most concerning toxicities for patients in the treatment of prostate cancer. The inconsistent evaluation of sexual function (SF) and limited follow-up data have necessitated additional study to clarify the rate and timing of erectile dysfunction after external beam radiotherapy (EBRT) for prostate cancer.
  
  
  METHODS
  A total of 143 men completed baseline data on SF before treatment and at the subsequent follow-up visits. A total of 1187 validated SF inventories were analyzed from the study participants. Multiple domains of SF (sex drive, erectile function, ejaculatory function, and overall satisfaction) were analyzed for < or =8 years of follow-up.
  
  
  RESULTS
  The median follow-up was 4.03 years. The strongest predictor of SF after EBRT was SF before treatment. For all domains of SF, the only statistically significant decrease in function occurred in the first 24 months after EBRT. SF stabilized 2 years after treatment completion, with no statistically significant change in any area of SF >2 years after the end of EBRT.
  
  
  CONCLUSIONS
  These data suggest that SF does not have a continuous decline after EBRT. Instead, SF decreases maximally within the first 24 months after EBRT, with no significant changes thereafter.
authors.affiliation: Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Siglin
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Kubicek
authors.forename: Benjamin
authors.initials: B
authors.lastname: Leiby
authors.forename: Richard K
authors.initials: RK
authors.lastname: Valicenti
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004542:Ejaculation / Q000502:physiology / Q000528:radiation effects; D007172:Erectile Dysfunction / Q000209:etiology* / Q000503:physiopathology; D005500:Follow-Up Studies; D006801:Humans; D007989:Libido / Q000502:physiology; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D010410:Penile Erection / Q000502:physiology / Q000528:radiation effects*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D013997:Time Factors