Abstract: PD71-02
Sources of Funding: A.R. is supported by a DOD PRTA award (W81XWH-13-1-0445) as well as a PCF Young Investigator Award and Patrick C. Walsh Investigator Grant.

Introduction

The prostate health index (PHI) is superior to PSA and other PSA-derivatives for the detection of prostate cancer (PCa). We sought to explore the utility of PHI density for the detection of clinically-significant PCa in a contemporary cohort of men presenting for diagnostic workup of PCa.

Methods

The study cohort included patients with elevated PSA (>2 ng/mL) and negative digital rectal examination who underwent PHI testing and prostate biopsy at our institution in 2015. Serum markers were prospectively measured per standard clinical pathway. PHI was calculated as [([-2]proPSA/free PSA) x (PSA)^1/2], and density calculations were performed using prostate volume as determined on transrectal ultrasound. Logistic regression was used to assess the ability of serum markers to predict clinically-significant PCa, defined as any Gleason score ≥7 cancer or Gleason score 6 cancer in >2 cores or >50% of any positive core._x000D_

Results

Of 118 men with PHI testing who underwent biopsy, 47 (39.8%) were found to have clinically-significant PCa on biopsy. The median PHI density was 0.70 (IQR 0.43-1.21); it was 0.53 (IQR 0.36-0.75) in men with negative biopsy or clinically-insignificant PCa and 1.21 (IQR 0.74-1.88) in men with clinically-significant PCa (p<0.001). Clinically-significant PCa was detected in 3.6% of men in the first quartile of PHI density (<0.43), 36.7% of men in the interquartile range (0.43-1.21) of PHI density, and 80.0% of men with PHI density >1.21 (p<0.001). Using a threshold of 0.43, PHI density was 97.9% sensitive and 38.0% specific for clinically-significant PCa, and 100% sensitive for Gleason score ≥7 disease. Compared to PSA (AUC 0.52), PSAD (AUC 0.70), %free PSA (AUC 0.75), and PHI (AUC 0.76), PHI density demonstrated the highest discriminative ability for clinically-significant PCa (AUC 0.84).

Conclusions

Based on this prospective single-center experience, PHI density could be used to avoid 38% of unnecessary biopsies while failing to detect only 2% of clinically-significant cancers.

Funding

A.R. is supported by a DOD PRTA award (W81XWH-13-1-0445) as well as a PCF Young Investigator Award and Patrick C. Walsh Investigator Grant.