RESUMO
Introduction: Modern image-guided biopsy pathways at diagnostic centres have greatly refined the investigations of men referred with suspected prostate cancer. However, the referral criteria from primary care are still based on historical prostate-specific antigen (PSA) cut-offs and age-referenced thresholds. Here, we tested whether better contemporary pathways and biopsy methods had improved the predictive utility value of PSA referral thresholds. Methods: PSA referral thresholds, age-referenced ranges and PSA density (PSAd) were assessed for positive predictive value (PPV) in detection of clinically significant prostate cancer (csPCa - histological ⩾ Grade Group 2). Data were analysed from men referred to three diagnostics centres who used multi-parametric magnetic resonance imaging (mpMRI)-guided prostate biopsies for disease characterisation. Findings were validated in a separate multicentre cohort. Results: Data from 2767 men were included in this study. The median age, PSA and PSAd were 66.4 years, 7.3 ng/mL and 0.1 ng/mL2, respectively. Biopsy detected csPCa was found in 38.7%. The overall area under the curve (AUC) for PSA was 0.68 which is similar to historical performance. A PSA threshold of ⩾ 3 ng/mL had a PPV of 40.3%, but this was age dependent (PPV: 24.8%, 32.7% and 56.8% in men 50-59 years, 60-69 years and ⩾ 70 years, respectively). Different PSA cut-offs and age-reference ranges failed to demonstrate better performance. PSAd demonstrated improved AUC (0.78 vs 0.68, p < 0.0001) and improved PPV compared to PSA. A PSAd of ⩾ 0.10 had a PPV of 48.2% and similar negative predictive value (NPV) to PSA ⩾ 3 ng/mL and out-performed PSA age-reference ranges. This improved performance was recapitulated in a separate multi-centre cohort (n = 541). Conclusion: The introduction of MRI-based image-guided biopsy pathways does not appear to have altered PSA diagnostic test characteristics to positively detect csPCa. We find no added value to PSA age-referenced ranges, while PSAd offers better PPV and the potential for a single clinically useful threshold (⩾0.10) for all age groups. Level of evidence: IV.
RESUMO
OBJECTIVES: To determine the extent to which clinically significant prostate cancer (csPCa) can be detected in a routine National Health Service setting in men with no previous biopsy, when multiparametric magnetic resonance imaging (mpMRI) is introduced into the diagnostic pathway. PATIENTS AND METHODS: In all, 1 090 mpMRIs were performed between July 2013 and April 2016 in biopsy-naïve men with an abnormal prostate-specific antigen level and/or digital rectal examination. Data were collected from patient records at the Royal Devon and Exeter NHS Foundation Trust. mpMRI Prostate Imaging Reporting and Data System (PI-RADS) scores were compared to transperineal or transrectal ultrasonography (TRUS)-guided biopsy findings as the reference standard. csPCa was defined as Gleason score of ≥3+4. The diagnostic accuracy of mpMRI was also assessed. RESULTS: The mpMRI was interpretable in 1 023 men and 792 underwent biopsy, of which 106 were transperineal. The median number of cores taken in transperineal and TRUS-guided biopsy were 10 and 6, respectively. The detection rate of csPCa was 37%; csPCa rose from 15% of PI-RADS 1 and 2 to 86% of PI-RADS 5. The sensitivity, negative predictive value, specificity, and positive predictive value were 82%, 85%, 59% and 54%, respectively. The study is limited by its retrospective nature and lack of reporting of follow-up for 'missed cancers'. Men with low mpMRI PI-RADS were also less likely to undergo biopsy. Whilst this selection bias may overestimate the detection rate of csPCa, this reflects the shared decisions patients and clinicians make in day-to-day practice outside of research centres. CONCLUSION: In a routine clinical setting, the higher the mpMRI PI-RADS, the greater the detection rate of csPCa in biopsy-naïve men. A normal mpMRI does not exclude csPCa; however, mpMRI may have utility in informing shared-decision making on whether to proceed to biopsy and subsequent treatment.
