Clinical implementation of pre-biopsy magnetic resonance imaging pathways for the diagnosis of prostate cancer

Up-to-Date Imaging and Diagnostic Techniques for Prostate Cancer: A Literature Review

Prostate cancer (PCa) faces great challenges in early diagnosis, which often leads not only to unnecessary, invasive procedures, but to over-diagnosis and treatment as well, thus highlighting the need for modern PCa diagnostic techniques. The review aims to provide an up-to-date summary of chronologically existing diagnostic approaches for PCa, as well as their potential to improve clinically significant PCa (csPCa) diagnosis and to reduce the proliferation and monitoring of PCa. Our review demonstrates the primary outcomes of the most significant studies and makes comparisons across the diagnostic efficacies of different PCa tests. Since prostate biopsy, the current mainstream PCa diagnosis, is an invasive procedure with a high risk of post-biopsy complications, it is vital we dig out specific, sensitive, and accurate diagnostic approaches in PCa and conduct more studies with milestone findings and comparable sample sizes to validate and corroborate the findings.

MRI-informed prostate biopsy: What the radiologist should know on quality in biopsy planning and biopsy acquisition

Quality is currently recognized as the pre-requisite for delivering the clinical benefits expected by magnetic resonance imaging (MRI)-informed prostate biopsy (MRI-i-PB) in patients with a suspicion for clinically significant prostate cancer (csPCa). The "quality chain" underlying MRI-i-PB is multidisciplinary in nature, and depends on several factors related to the patient, imaging technique, image interpretation and biopsy procedure. This review aims at making the radiologist aware of biopsy-related factors impacting on MRI-i-PB quality, both in terms of biopsy planning (threshold for biopsy decisions, association with systematic biopsy and number of targeted cores) and biopsy acquisition (biopsy route, targeting technique, and operator's experience). While there is still space for improvement and better standardization of several biopsy-related procedures, current evidence suggests that high-quality MRI-i-PB can be delivered by acquiring and increased the number of biopsy cores targeted to suspicious imaging findings and perilesional area ("focal saturation biopsy"). On the other hand, uncertainty still exists as to whether software-assisted fusion of MRI and transrectal ultrasound images can outperform cognitive fusion strategy. The role for operator's experience and quality assurance/quality control procedures are also discussed.

Quality checkpoints in the MRI-directed prostate cancer diagnostic pathway

Multiparametric MRI of the prostate is now recommended as the initial diagnostic test for men presenting with suspected prostate cancer, with a negative MRI enabling safe avoidance of biopsy and a positive result enabling MRI-directed sampling of lesions. The diagnostic pathway consists of several steps, from initial patient presentation and preparation to performing and interpreting MRI, communicating the imaging findings, outlining the prostate and intra-prostatic target lesions, performing the biopsy and assessing the cores. Each component of this pathway requires experienced clinicians, optimized equipment, good inter-disciplinary communication between specialists, and standardized workflows in order to achieve the expected outcomes. Assessment of quality and mitigation measures are essential for the success of the MRI-directed prostate cancer diagnostic pathway. Quality assurance processes including Prostate Imaging-Reporting and Data System, template biopsy, and pathology guidelines help to minimize variation and ensure optimization of the diagnostic pathway. Quality control systems including the Prostate Imaging Quality scoring system, patient-level outcomes (such as Prostate Imaging-Reporting and Data System MRI score assignment and cancer detection rates), multidisciplinary meeting review and audits might also be used to provide consistency of outcomes and ensure that all the benefits of the MRI-directed pathway are achieved.

Implications of the European Association of Urology Recommended Risk Assessment Algorithm for Early Prostate Cancer Detection

Patient summary

A Prospective Multicenter Comparison Study of Risk-adapted Ultrasound-directed and Magnetic Resonance Imaging-directed Diagnostic Pathways for Suspected Prostate Cancer in Biopsy-naïve Men

BACKGROUND

European Association of Urology guidelines recommend a risk-adjusted biopsy strategy for early detection of prostate cancer in biopsy-naïve men. It remains unclear which strategy is most effective. Therefore, we evaluated two risk assessment pathways commonly used in clinical practice.

OBJECTIVE

To compare the diagnostic performance of a risk-based ultrasound (US)-directed pathway (Rotterdam Prostate Cancer Risk Calculator [RPCRC] #3; US volume assessment) and a magnetic resonance imaging (MRI)-directed pathway.

DESIGN, SETTING, AND PARTICIPANTS

This was a prospective multicenter study (MR-PROPER) with 1:1 allocation among 21 centers (US arm in 11 centers, MRI arm in ten). Biopsy-naïve men with suspicion of prostate cancer (age ≥50 yr, prostate-specific antigen 3.0-50 ng/ml, ± abnormal digital rectal examination) were included.

INTERVENTION

Biopsy-naïve men with elevated risk of prostate cancer, determined using RPCRC#3 in the US arm and Prostate Imaging Reporting and Data System scores of 3-5 in the MRI arm, underwent systematic biopsies (US arm) or targeted biopsies (MRI arm).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the proportion of men with grade group (GG) ≥2 cancer. Secondary outcomes were the proportions of biopsies avoided and GG 1 cancers detected. Categorical (nonparametric) data were assessed using the Mann-Whitney U test and χ² tests.

RESULTS AND LIMITATIONS

A total of 1965 men were included in the intention-to-treat population (US arm n = 950, MRI arm n = 1015). The US and MRI pathways detected GG ≥2 cancers equally well (235/950, 25% vs 239/1015, 24%; difference 1.2%, 95% confidence interval [CI] -2.6% to 5.0%; p = 0.5). The US pathway detected more GG 1 cancers than the MRI pathway (121/950, 13% vs 84/1015, 8.3%; difference 4.5%, 95% CI 1.8-7.2%; p < 0.01). The US pathway avoided fewer biopsies than the MRI pathway (403/950, 42% vs 559/1015, 55%; difference -13%, 95% CI -17% to -8.3%; p < 0.01). Among men with elevated risk, more GG ≥2 cancers were detected in the MRI group than in the US group (52% vs 43%; difference 9.2%, 95% CI 3.0-15%; p < 0.01).

CONCLUSIONS

Risk-adapted US-directed and MRI-directed pathways detected GG ≥2 cancers equally well. The risk-adapted US-directed pathway performs well for prostate cancer diagnosis if prostate MRI capacity and expertise are not available. If prostate MRI availability is sufficient, risk assessment should preferably be performed using MRI, as this avoids more biopsies and detects fewer cases of GG 1 cancer.

PATIENT SUMMARY

Among men with suspected prostate cancer, relevant cancers were equally well detected by risk-based pathways using either ultrasound or magnetic resonance imaging (MRI) to guide biopsy of the prostate. If prostate MRI availability is sufficient, risk assessment should be performed with MRI to reduce unnecessary biopsies and detect fewer irrelevant cancers.