The Prostate Health Index (phi) selectively identifies clinically-significant prostate cancer - Abstract

PURPOSE: The Prostate Health Index (phi) is a new test combining total, free and [-2]proPSA into a single score.

It was recently approved by the FDA and is now commercially available in the U.S., Europe and Australia. We investigate whether phi improves specificity for detecting clinically significant prostate cancer and can help reduce prostate cancer over diagnosis.

MATERIALS AND METHODS: From a multicenter prospective trial we identified 658 men age 50 years or older with prostate specific antigen 4 to 10 ng/ml and normal digital rectal examination who underwent prostate biopsy. In this population we compared the performance of prostate specific antigen, % free prostate specific antigen, [-2]proPSA and phi to predict biopsy results and, specifically, the presence of clinically significant prostate cancer using multiple criteria.

RESULTS: The Prostate Health Index was significantly higher in men with Gleason 7 or greater and "Epstein significant" cancer. On receiver operating characteristic analysis phi had the highest AUC for overall cancer (AUCs phi 0.708, percent free prostate specific antigen 0.648, [-2]proPSA 0.550 and prostate specific antigen 0.516), Gleason 7 or greater (AUCs phi 0.707, percent free prostate specific antigen 0.661, [-2]proPSA 0.558, prostate specific antigen 0.551) and significant cancer (AUCs phi 0.698, percent free prostate specific antigen 0.654, [-2]proPSA 0.550, prostate specific antigen 0.549). At the 90% sensitivity cut point for phi (a score less than 28.6) 30.1% of patients could have been spared an unnecessary biopsy for benign disease or insignificant prostate cancer compared to 21.7% using percent free prostate specific antigen.

CONCLUSIONS: The new phi test outperforms its individual components of total, free and [-2]proPSA for the identification of clinically significant prostate cancer. Phi may be useful as part of a multivariable approach to reduce prostate biopsies and over diagnosis.

Written by:
Loeb S, Sanda MG, Broyles DL, Shin SS, Bangma CH, Wei JT, Partin AW, Klee GG, Slawin KM, Marks LS, van Schaik RH, Chan DW, Sokoll LJ, Cruz AB, Mizrahi IA, Catalona WJ.   Are you the author?
Department of Urology, NYU Langone Medical Center, New York, New York; Department of Urology, Emory University and Emory Healthcare, Atlanta, Georgia; Beckman Coulter Incorporated, Carlsbad, California; Department of Urology, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Urology, University of Michigan School of Medicine, Ann Arbor, Michigan; Department of Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota; Vanguard Urologic Institute and Texas Prostate Center, Houston, Texas; Department of Urology, University of California Los Angeles, Los Angeles, California; Clinical Chemistry, Erasmus University Medical Center, Rotterdam, the Netherlands; Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.  

Reference: J Urol. 2014 Nov 15. pii: S0022-5347(14)04900-3.
doi: 10.1016/j.juro.2014.10.121

PubMed Abstract
PMID: 25463993 Prostate Cancer Section