Reply by Authors

Abstract

<p>We thank Dr de la Calle and Dr Pavlovich for the kind comments. Prostate volume has always been an important element in assessment of risk of clinically significant prostate cancer (csPCa), from PSA density to risk calculators.^{<a href="https://www.auajournals.org/doi/10.1097/JU.0000000000003450.02#R1">1</a>} Prostate volume is readily available in all men with MRI performed. The beauty of PSA density or Prostate Health Index (PHI) density is their ease of calculation and use, compared with a multivariable “PHI risk score.”</p><p>In Figure 1 of the article, the AUCs in predicting csPCa in men with Prostate Imaging Reporting & Data System 3 lesions using PSA, PSA density, PHI, and PHI density were 0.58, 0.70, 0.76, and 0.80, respectively.^{<a href="https://www.auajournals.org/doi/10.1097/JU.0000000000003450.02#R2">2</a>} The difference in AUC of 10% between PHI density and PSA density was both clinically and statistically significant.</p><p>The cost of PHI in Asia is currently less than USD $100, and we believe PHI is significantly cheaper than most other commercially available blood or urine tests on the market, with comparable performance. PHI is widely available in the U.S., Europe, and Asia, and it can be done in local laboratories without the need for shipping to another continent.</p><p>In a recently published paper by Liu et al, pre-biopsy PHI or PHI density predicted 6-year risk of csPCa in men with initial negative prostate biopsy.^{<a href="https://www.auajournals.org/doi/10.1097/JU.0000000000003450.02#R3">3</a>} At 6 years of follow-up, csPCa was diagnosed in 0% and 21.0% of men with PHI density of <0.4 and ≥1.2, respectively. Therefore, PHI and PHI density can provide a guide to how frequently a patient should be followed.</p>