Peripheral zone volume ratio (PZ-ratio) is relevant with biopsy results and can increase the accuracy of current diagnostic modality

Abstract

The current diagnostic modality of prostate cancer based on prostate specific antigen (PSA) and systematic biopsy is far from ideal in terms of over-diagnosing indolent prostate cancer and missing significant ones. Thus we integrated the peripheral zone volume ratio (PZ-ratio) for diagnostic refinement. This retrospective study included 247 consecutive patients who underwent initial transrectal ultrasound-guided systematic prostate biopsy from April 2014 to November 2015. Prostate volume was determined by semi-automatic contour on axial T2 weighted magnetic resonance imaging (MRI). PZ-ratio was inversely correlated with age (r = −0.36, p <0.0001). Adding PZ-ratio and MRI findings to the current predictive model (age, PSA density, percent-free PSA) significantly increased diagnostic accuracy in all patients (AUC: 0.871 vs. 0.812, p = 0.0059), but not in patient subgroup with PSA 4–10 ng/ml (AUC: 0.863 vs. 0.803, p = 0.12). The new model also significantly reduced the number of unnecessary biopsies while missing less significant cancers at a probability threshold of 25%. PZ-ratio is a potential tool in predicting biopsy results, and when added alone or in combination with MRI findings, the diagnostic accuracy can be further enhanced.

Benign prostate hyperplasia as a potential protective factor against prostate cancer: Insights from a magnetic resonance imaging study of compositional characteristics

“…Current literature suggests that the mechanism of BPH reducing the risk of cancer may arise from enlarging central gland compressing the peripheral zone, resulting in decreased thickness, atrophy, fibrosis, and decreased density 21–23 . Our results largely differ from previous studies as the central gland volumes, not peripheral zone characteristics, drove the decreased odds of Pca.…”

Is PSA density of the peripheral zone as a useful predictor for prostate cancer in patients with gray zone PSA levels?

“…In Chang et al's study [22], the peripheral zone volume ratio (PZ-ratio) was calculated by dividing the peripheral zone's measured volume by the total prostate volume using mpMRI. The AUC value of PZ-ratio as a predictor of prostate cancer in patients with gray zone PSA level was reported to be 0.676, similar to that of EPHPSA, and the AUC value increased to 0.863 when using MRI and PZ ratio.…”

The roles of MRI-based prostate volume and associated zone-adjusted prostate-specific antigen concentrations in predicting prostate cancer and high-risk prostate cancer

“…[15] However, measurement of PV using TRUS is less accurate compared with MRI. [14, 16, 17] Further, MRI assesses PV with high reproducibility and accuracy compared with TRUS because of interobserver variability associated with the latter. [18]…”