title: Development of clinical models for predicting erectile function after localized prostate cancer treatment.
abstract: OBJECTIVE
  To develop clinical prediction models estimating the probability of maintaining erections adequate for intercourse 2 years after prostate cancer treatment, based on pretreatment characteristics.
  
  
  METHODS
  Study participants consisted of prostate cancer patients with localized disease and functional erections before undergoing surgery (n = 536) or radiation therapy (n = 240) at a single USA institution. Baseline patient- and treatment-related data were collected from a clinical database and through chart review. Erectile function at 2 years post-treatment was prospectively assessed through a self-administered single-item measure. Multivariate logistic regression using backward selection was used to derive clinical prediction models to predict erectile function at 2 years for surgery and radiation therapy patients; the models were internally validated using bootstrapping methods.
  
  
  RESULTS
  The final prediction model for surgery patients included the predictor variables of age, body mass index, smoking, diabetes, hypertension and nerve-sparing procedures, whereas the model for radiation therapy patients included hypertension, risk category and radiation technique. The new models showed acceptable calibration and discrimination: c-statistic = 0.71 (95% confidence interval 0.68-0.76) for surgery and 0.66 (95% confidence interval 0.61-0.74) for radiation therapy models.
  
  
  CONCLUSIONS
  New clinical prediction models based on patient and treatment characteristics show promising accuracy in predicting erectile function at 2 years in patients treated with surgery and radiation for localized prostate cancer. More work is required to confirm and validate these models in different patient populations.
authors: Center for Outcomes Research and Evaluation, Maine Medical Center, Portland, Maine, USA.
authors: Amy E
authors: AE
authors: Haskins
authors: Paul K J
authors: PK
authors: Han
authors: Frances L
authors: FL
authors: Lucas
authors: Ian
authors: I
authors: Bristol
authors: Moritz
authors: M
authors: Hansen
mesh_terms: D000368:Aged; D007172:Erectile Dysfunction / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D005544:Forecasting; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D010410:Penile Erection / Q000502:physiology*; D011379:Prognosis; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000503:physiopathology* / Q000532:radiotherapy / Q000601:surgery; D011788:Quality of Life
keywords: decision support techniques; erectile dysfunction; prostatectomy; prostatic neoplasms; radiotherapy