title: Initial extended transrectal prostate biopsy--are more prostate cancers detected with 18 cores than with 12 cores?
abstract: OBJECTIVE
  We retrospectively investigated the detection rates of prostate cancer, high grade prostatic intraepithelial neoplasia and atypical glands suggestive of carcinoma by initial 18 and 12-core prostate biopsy.
  
  
  METHODS
  A total of 3,460 consecutive patients with prostate specific antigen between 2.5 and 15 ng/ml underwent 12 (1,684) or 18 (1,776) core prostate biopsy under local anesthesia at 2 departments that adopted the same indications for performing biopsy. Biopsies were evenly distributed throughout the prostate in 6 sectors. In the 12-core prostate biopsy group 2 samples were obtained from each sector and in the 18-core prostate biopsy group 1 additional core was taken from each sector.
  
  
  RESULTS
  The cancer detection rate in patients who underwent 18-core prostate biopsy was not different from the rate in those who underwent 12-core prostate biopsy (39.9% and 38.4%, p = 0.37), nor did the detection of atypical glands suggestive of carcinoma differ significantly between the 2 groups (2.9% and 3.3%, respectively, p = 0.33). However, 18-core prostate biopsy detected a significantly higher percent of cases of high grade prostatic intraepithelial neoplasia (20.0% vs 12.9%, p = 0.001). The cancer detection rate was higher with 18 than with 12-core prostate biopsy in patients with a prostate volume of 55 cc or greater (31.5% vs 24.8%, p = 0.01) but not in those with a prostate volume of less than 55 cc (54.3% and 53.0%, respectively, p = 0.7). Moreover, we determined that patients with positive digital rectal examination findings do not need 18-core prostate biopsy as opposed to 12-core prostate biopsy.
  
  
  CONCLUSIONS
  Compared with 12-core prostate biopsy, 18-core prostate biopsy detects significantly more cases of high grade prostatic intraepithelial neoplasia. However, 18-core prostate biopsy detects a significantly higher number of cancer only in patients with a prostate volume of 55 cc or greater.
authors.affiliation: Department of Urology, University Vita-Salute, Scientific Institute San Raffaele, Milan, Italy. scattoni.vincenzo@hsr.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Scattoni
authors.forename: Marco
authors.initials: M
authors.lastname: Roscigno
authors.forename: Marco
authors.initials: M
authors.lastname: Raber
authors.forename: Federico
authors.initials: F
authors.lastname: Dehò
authors.forename: Tommaso
authors.initials: T
authors.lastname: Maga
authors.forename: Matteo
authors.initials: M
authors.lastname: Zanoni
authors.forename: Matteo
authors.initials: M
authors.lastname: Riva
authors.forename: Mattia
authors.initials: M
authors.lastname: Sangalli
authors.forename: Luciano
authors.initials: L
authors.lastname: Nava
authors.forename: Bruno
authors.initials: B
authors.lastname: Mazzoccoli
authors.forename: Massimo
authors.initials: M
authors.lastname: Freschi
authors.forename: Giorgio
authors.initials: G
authors.lastname: Guazzoni
authors.forename: Patrizio
authors.initials: P
authors.lastname: Rigatti
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology*; D019048:Prostatic Intraepithelial Neoplasia / Q000473:pathology; D011471:Prostatic Neoplasms / Q000473:pathology*; D012189:Retrospective Studies