Head-to-head Comparison of Transrectal Ultrasound-guided Prostate Biopsy Versus Multiparametric Prostate Resonance Imaging with Subsequent Magnetic Resonance-guided Biopsy in Biopsy-naïve Men with Elevated Prostate-specific Antigen: A Large Prospective Multicenter Clinical Study

Multivariate risk prediction tools including MRI for individualized biopsy decision in prostate cancer diagnosis: current status and future directions

Background and purpose

Individualized risk-adapted algorithms in prostate cancer (PCa) diagnosis using predictive prebiopsy variables in addition to prostate-specific antigen value may result in a considerable reduction of unnecessary systematic biopsies. Multi-parametric magnetic resonance imaging (mpMRI) has emerged as a secondary prediction tool that can further improve the detection of clinically significant prostate cancer (csPCa). This review explores the performance of new MRI risk models for indicating a biopsy for prostate cancer diagnosis.

Results and considerations

The area under the receiver-operating characteristic curve for detecting csPCa varies between 0.64 and 0.91 in biopsy-naïve men, and between 0.78 and 0.93 in men with a previous negative biopsy. The utility of multivariate risk prediction tools including MRI suspicion scores as an extra input parameter has the potential to avoid a notable number of biopsies and detection of clinically insignificant PCa at a low price of missing some csPCa. The trade-off depends on the risk threshold that is chosen. In biopsy-naïve men a net benefit was obtained at a risk threshold of above 10% for csPCa in most MRI risk prediction models. All constructed MRI risk models used (referral) patient cohorts with high prevalence of csPCa. Using more representative cohorts from daily clinical screening, net benefit may attenuate at lower risk thresholds. Strengths and limitations of these models are discussed.

Future directions

To assess their wider applicability, in-depth analysis of mpMRI predictive qualities should be further investigated, in combination with required external validation of these models in a multicenter setting with large prospective datasets.

[Fusion biopsies for primary diagnosis of prostate cancer : Implementation, benefits, and clinical aspects]

Prostate carcinoma is one of the most common tumors worldwide. Histological confirmation by biopsy is an obligatory part of the diagnostic approach. The main problem of the 10-12-fold transrectal ultrasound-guided (TRUS) biopsy, which has so far been regarded as the gold standard, is the underdiagnosis of clinically significant cancer. MRI-based procedures, so-called fusion biopsies, have shown superior results when compared to conventional biopsies. There are three different approaches (cognitive and software-based MRI/TRUS fusion and in-bore biopsy) with comparable detection rates but differences in the technical aspects and time involvement. In order to reduce fusion errors, targeted biopsies should consist of multiple cores. There is currently no clear preference for the access pathway (transrectal or transperineal), but clinical parameters such as infection risk or location of the tumor can influence the decision. While the German S3 guideline considers MRI prior to primary biopsy to be optional, the 2019 European Association of Urology guidelines already recommend MRI prior to biopsy for all patients. The combination of MRI-targeted and systematic biopsy offers the highest detection rates with the disadvantage that more low-risk tumors are diagnosed. Both the patient and the urologist benefit from an improved informative value of the biopsy when deciding on active surveillance as well as when planning invasive therapies.

[Active surveillance of prostate cancer : An update]

Prostate cancer is a heterogeneous disease. In cases of low-risk prostate cancer, active surveillance represents an attractive alternative treatment. Significant complications of a definitive treatment can therefore be delayed or completely avoided. Despite strict inclusion criteria for active surveillance, the diagnosis of low-risk prostate cancer can be inaccurate and there is therefore a risk of missing the optimal point in time for definitive treatment. Multimodal diagnostics and continuous aftercare are therefore crucial.

[Focal therapy for prostate cancer]

Focal therapy (FT) should have the same oncological efficacy as whole gland therapy with fewer side effects. Precise diagnosis with PI-RADS v2 standard multiparametric magnetic resonance imaging (MRI) and fusion or template biopsy is a basic prerequisite. Numerous ablation technologies and treatment strategies have been developed, including hemiablation. Treatment success is still inconsistently defined. The only large randomized study available compares one of the procedures to standard therapy. Therefore, even in 2019, FT must still be regarded as experimental and should only be carried out within the context of studies. Follow-up should correspond to active surveillance (AS), including MRI and fusion biopsy. Advantages and disadvantages of each ablation technique should be taken into consideration as well as the suitability of certain regions in the gland. Ideally, an individualized "à la carte" selection of various procedures should be offered. FT is well suited for patients with highly localized cancers at intermediate risk if standard therapies or AS is not possible or has been refused.