title: Effectiveness of percent free prostate specific antigen as a predictor of prostate cancer detection on repeat biopsy.
abstract: BACKGROUND
  The aim of this study was to identify predictors that can increase the accuracy of detecting prostate cancer on subsequent biopsies.
  
  
  METHODS
  Between 1998 and 2003, a total of 235 men with prostate specific antigen (PSA) levels between 4.0 and 20 ng/mL underwent one or more systematic needle biopsies of the prostate. Of these men, 73 (31.1%) underwent one repeat biopsy and 26 (11.1%) underwent two or more repeat biopsies. We evaluated the results of prostate biopsies in relation to the morbidity of prostate cancer detected on repeat biopsies.
  
  
  RESULTS
  Of the 73 men who underwent repeat biopsy, 16 (21.9%) had prostate cancer. Twenty-six men with one negative re-biopsy underwent two or more repeat biopsies, and five of these patients were found to have early stage prostate cancer. On repeat biopsy, there was a significant difference in percent free PSA between the cancer-detected group and the no-cancer-detected group (P < 0.01). A receiver operating characteristics (ROC) curve gave an optimal cut-off value for percent free PSA of 11%, demonstrating a significant difference in the cancer detection rate on repeat biopsy (P = 0.0009). Analysis of the data for re-biopsies showed that cancer-detected cases showed a raised PSA value and a simultaneously reduced percent free PSA (these differences were statistically significant).
  
  
  CONCLUSIONS
  A low percent free PSA level increased the probability of a positive result in repeat biopsy. An increase in the accuracy of detecting cancer, especially on repeat biopsy, will promote the detection of more early stage prostate cancer.
authors.affiliation: Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
authors.forename: Hiroji
authors.initials: H
authors.lastname: Uemura
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nakamura
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hasumi
authors.forename: Shinpei
authors.initials: S
authors.lastname: Sugiura
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Fujinami
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Miyoshi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yao
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Kubota
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology*
chemical_list: D017430:Prostate-Specific Antigen