Reduction of MRI-targeted biopsies in men with low-risk prostate cancer on active surveillance by stratifying to PI-RADS and PSA-density, with different thresholds for significant disease

Abstract

BackgroundThe fear of undergrading prostate cancer (PCa) in men on active surveillance (AS) have led to strict criteria for monitoring, which have resulted in good long-term cancer-specific survival, proving the safety of this approach. Reducing undergrading, MRI-targeted biopsies are increasingly used in men with low-risk disease despite their undefined role yet. The objective of this study is to investigate the rate of upgrading using MRI-targeted biopsies in men with low-risk disease on AS, stratified on the basis of PI-RADS and PSA-density, with the aim to reduce potential unnecessary repeat biopsy procedures.MethodsA total of 331 men were prospectively enrolled following the MRI-PRIAS protocol. MR imaging was according to Prostate Imaging Reporting and Data System (PI-RADSv2) guidelines. Suspicious MRI lesions (PI-RADS 3–5) were additionally targeted by MRI-TRUS fusion biopsies. Outcome measure was upgrading to Gleason score (GS) ≥3+4 with MRI-targeted biopsies, stratified for PI-RADS and PSA-density.ResultsIn total, 25% (82/331) of men on AS showed upgrading from GS 3+3. Only 3% (11/331) was upgraded to GS ≥8. In 60% (198/331) a suspicious MRI lesion was identified, but in only 41% (82/198) of men upgrading was confirmed. PI-RADS 3, 4 and 5 categorized index lesions, showed upgrading in 30%, 34% and 66% of men, respectively. Stratification to PI-RADS 4–5, instead of PI-RADS 3–5, would have missed a small number of high volume Gleason 4 PCa in PI-RADS 3 category. However, further stratification into PI-RADS 3 lesions and PSA-density <0.15 ng/mL2 could result in a safe targeted biopsy reduction of 36% in this category, without missing any upgrades.ConclusionsStratification with the combination of PI-RADS and PSA-density may reduce unnecessary additional MRI biopsy testing. Overall, the high rate of detected upgrading in men on AS may result in an unintended tightening of continuing in AS. Since patients, included under current AS criteria showed extremely favorable outcome, there might be no need to further restrict continuing on AS with MRI and targeted biopsies.

Standardized Magnetic Resonance Imaging Reporting Using the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation Criteria and Magnetic Resonance Imaging/Transrectal Ultrasound Fusion with Transperineal Saturation Biopsy to Select Men on Active Surveillance

“…Similarly, Shaw et al reported superiority of targeted biopsies (TB) over standard TRUS-biopsies [12]. Recent studies emphasize the benefit of additional MRI and MRI-guided biopsy for AS [7,13,14]. In a previously published AS-cohort with a two-year follow-up, our group demonstrated a significantly decreased AS disqualification with initial MRI/TRUS-fusion biopsy, compared to initial 12-core-TRUS-biopsy [7].…”

Four‐year outcomes from a multiparametric magnetic resonance imaging (MRI)‐based active surveillance programme: PSA dynamics and serial MRI scans allow omission of protocol biopsies

“…Visible abnormalities were reported as likely to be malignant or equivocal for malignancy. It is possible that five‐point MRI risk categorization may have better risk‐stratified patients in a larger cohort . Kaplan–Meier analysis showed well‐calibrated risk of progression based on the three MRI risk levels that we assigned.…”

MRI in early prostate cancer detection: how to manage indeterminate or equivocal PI-RADS 3 lesions?

“…On the basis of the studies reviewed, comprising 8,252 men ( 6 - 21 ), PI-RADS category 1–2, 3, 4 and 5 appear to be equally distributed in all suspicious or positive MRIs, represented by approximately one fourth for each category ( Table 1 ). Furthermore, this distribution is comparable for men with first biopsies (total n=1,855), previously negative biopsies (total n=1,355), and men with active surveillance biopsies (total n=1,198).…”

“…Some of these studies reported their results according to the Standards of reporting for MRI-targeted biopsy studies (START) of the prostate ( 22 ), and Gleason grading was correlated to the PI-RADS assessment score 1 to 5. Summary results of these studies ( 7 , 8 , 10 , 12 , 21 , 23 ) are shown in Figures 3 and S1 .…”

“… Histology outcome by Gleason score (GS) of PI-RADS assessment categories 3, 4 and 5, with subsequently MRI-targeted biopsies, in men with first biopsies (A), previous negative biopsies (B), and active surveillance biopsies (C). Cumulated data, generated by individual reports ( 7 , 8 , 10 , 12 , 13 , 21 ) (see Figure S1 ). …”