Timo Soeterik

172 CHAPTER 10 more lymph node dissections in patients without nodal metastasis (higher false positive rate). Although our analysis showed that mpMRI T-stage is a valuable alternative to DRE T-stage for nomogram-based risk prediction, clinicians should be aware of the stage migration use of mpMRI T-stage initiates, potentially resulting in increased number of unnecessary lymph node dissections. The selection of patients for extended pelvic lymph node dissection (ePLND), using set thresholds (with variation allowed between hospitals and urologists, between 5% to 15%) for risk of LNI, forms an important limitation of the present study; leading to a study population with a relatively high prevalence of LNI. This aspect could limit the generalisability of our study results to patients with a predicted LNI risk for the lower thresholds (0 – 10%). In addition, the selection of patients can also explain the counterintuitive findings regarding the net benefit; as decision curve analysis showed that a “treat all” approach (subjecting all patients to ePLND), would be superior compared to nomogram-based selection. Nevertheless, although the study regards a selected subgroup, we assume the population to be suitable for testing the primary hypothesis; confirming mpMRI T-stage is at least equal to DRE T-stage when used for nomogram-based LNI risk prediction. FUTURE PERSPECTIVES Optimisation of active surveillance in the present MRI era Data of studies with MRI-based AS protocols will reach greater maturity in the near future, yielding valuable information regarding the added value of MRI application in AS. The preliminary outcomes indicate that baseline MRI can further discriminate indolent tumours from those likely to become clinically significant. 14 In addition, performing MRI before entering AS was associated with lower rates of discontinuation at 15 months (14% versus 26-28% in MRI-naïve men). 15 Use of MRI-based risk stratification tools and scoring systems such as PI-RADS and PRECISE can help to reduce the number of necessary repeat biopsies, decreasing AS burden for the patient. 14,16,17 The mid-term results of an AS cohort including full MRI-led monitoring are promising, showing comparable discontinuation, mortality and metastasis rates compared with those reported in standard AS, while drastically reducing the number of repeat biopsies. 18 Although the long-term results are to be awaited, these results show the potential of full MRI-based AS monitoring. Impact of MRI on prostate cancer pre-treatment risk prediction tools Application of MRI and target biopsy information are expected to further shift the paradigm of predictive modelling in prostate cancer. It has been established previously that application of MRI-guided target biopsies, combined with concomitant systematic biopsies, leads to decreased ISUP upgrading rates at final pathology. 19,20 The more accurate the ISUP grade can be assessed preoperatively, the more accurate risk prediction by