Robustness of free prostate specific antigen measurements to reduce unnecessary biopsies in the 2.6 To 4.0 ng./ml. range

Kimberly A. Roehl*, Jo Ann V Antenor, William J. Catalona

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

82 Scopus citations


Purpose: Prostate specific antigen (PSA) cutoffs lower than 4.0 ng./ml. are being evaluated more frequently but lower PSA cutoffs increase the number of prostatic biopsies. PSA exists in several forms free and complexed to proteins. Percent free PSA is lower in men with prostate cancer. Accordingly, free PSA and complexed PSA have been used to distinguish between cancer and benign disease in the diagnostic gray zone of 4 to 10 ng./ml. to eliminate unnecessary biopsies. There are limited data on the robustness of free PSA measurements in the 2.6 to 4.0 ng./ml. total PSA range. Materials and Methods: We evaluated percent free PSA measurements to discriminate between cancer and benign conditions in 965 consecutive volunteers in a prostate cancer screening study who underwent prostatic biopsy for a PSA of 2.6 to 4.0 ng./ml. and had benign digital rectal examination. Results: Overall 25% of men had cancer detected. A 25% free PSA cutoff detected 85% of cancers and avoided 19% of negative (cancer-free) biopsies, while a 30% free PSA cutoff detected 93% of cancers and avoided only 9% of negative biopsies. Of those men who underwent radical prostatectomy 132 (80%) had pathologically organ confined tumors. Only 5% of these tumors fulfilled the published pathological criteria for possibly clinically unimportant tumors. Conclusions: Percent free PSA provides risk assessment but does not eliminate many unnecessary prostatic biopsies while maintaining a high sensitivity in the narrow total PSA range of 2.6 to 4.0 ng./ml.

Original languageEnglish (US)
Pages (from-to)922-925
Number of pages4
JournalJournal of Urology
Issue number3
StatePublished - Sep 2002


  • Biopsy
  • Prostate-specific antigen
  • Prostatic neoplasms

ASJC Scopus subject areas

  • Urology


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