Purpose: We evaluated the ability of PHI to discriminate aggressive prostate cancer from indolent or no cancer in a biopsy naïve population.
Materials and methods: Two independent prospective cohorts of 561 and 395 subjects, respectively, with no prior prostate biopsy who were enrolled at different clinical sites were used to validate the results. We compared the diagnostic specificity of PHI to prebiopsy total and percent free prostate specific antigen using prostate biopsy results. We also determined the optimal PHI threshold to discriminate aggressive prostate cancer (Gleason score 7 or greater) from indolent or no prostate cancer (Gleason score 6 or less).
Results: In the primary cohort higher PHI values were significantly associated with Gleason score 7 or greater. The AUC to detect aggressive prostate cancer was 0.815. At 95% sensitivity PHI specificity was 36.0% vs 17.2% and 19.4% for total and percent free prostate specific antigen, respectively. At 95% sensitivity for detecting aggressive prostate cancer the optimal PHI cutoff was 24, which would help avoid 41% of unnecessary biopsies. A cutoff of 24 led to 36% biopsies avoided with few aggressive cancers missed. These results were confirmed in the validation cohort.
Conclusions: The PHI detected aggressive prostate cancer with better specificity than total and percent free prostate specific antigen in a biopsy naïve population. It could be a useful tool to decrease unnecessary prostate biopsies.
Keywords: biopsy; nomograms; prostate; prostate-specific antigen; prostatic neoplasms.
Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.