title: The number of cores taken in patients diagnosed with a single microfocus at initial biopsy is a major predictor of insignificant prostate cancer.
abstract: OBJECTIVE
  Patients with a single microfocus of prostate cancer at initial biopsy represent the ideal candidates for active surveillance. We investigate whether the number of cores taken affects the concordance rate between microfocus of prostate cancer and the confirmation of a pathologically insignificant prostate cancer at radical prostatectomy.
  
  
  METHODS
  Data were analyzed from 233 patients with a single microfocus of prostate cancer at initial transrectal prostate biopsy (a single focus of Gleason 6 involving 5% or less of the core) subsequently treated with radical prostatectomy. The chi-square test, cubic spline analyses and logistic regression analyses were used to depict the relationship between the number of cores taken and the probability of confirming the presence of an indolent disease (pathologically confirmed insignificant prostate cancer defined as radical prostatectomy Gleason score 6 or less, tumor volume 0.5 ml or less and organ confined disease).
  
  
  RESULTS
  Overall 65 patients (27.9%) showed pathologically confirmed insignificant prostate cancer at radical prostatectomy. The rate of pathologically confirmed insignificant prostate cancer was 3.8%, 29.6% and 39.4% in patients who underwent biopsy of 12 or fewer cores, 13 to 18 cores and 19 or more cores, respectively (p <0.001). After adjusting for the available confounders, age (p = 0.04), number of cores taken (p <0.001) and prostate specific antigen density (p <0.02) were independent predictors of pathologically confirmed insignificant prostate cancer.
  
  
  CONCLUSIONS
  Of patients diagnosed with a single microfocus of prostate cancer the number of biopsy cores taken was a major independent predictor of having pathologically confirmed insignificant prostate cancer at radical prostatectomy. Therefore, when active surveillance is considered as a possible alternative in patients with microfocus of prostate cancer, the number of cores taken should be taken into account in decision making.
authors.affiliation: Department of Urology, Urological Research Institute, University Vita-Salute San Raffaele, Milan, Italy. l.villa@hotmail.it
authors.forename: Luca
authors.initials: L
authors.lastname: Villa
authors.forename: Umberto
authors.initials: U
authors.lastname: Capitanio
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
authors.forename: Firas
authors.initials: F
authors.lastname: Abdollah
authors.forename: Nazareno
authors.initials: N
authors.lastname: Suardi
authors.forename: Andrea
authors.initials: A
authors.lastname: Salonia
authors.forename: Andrea
authors.initials: A
authors.lastname: Gallina
authors.forename: Massimo
authors.initials: M
authors.lastname: Freschi
authors.forename: Andrea
authors.initials: A
authors.lastname: Russo
authors.forename: Fabio
authors.initials: F
authors.lastname: Castiglione
authors.forename: Marco
authors.initials: M
authors.lastname: Bianchi
authors.forename: Patrizio
authors.initials: P
authors.lastname: Rigatti
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Scattoni
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D062005:Biopsy, Large-Core Needle / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading / Q000379:methods*; D011237:Predictive Value of Tests; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D015203:Reproducibility of Results; D012189:Retrospective Studies; D047368:Tumor Burden