Timo Soeterik

170 CHAPTER 10 an unreliable tool to exclude stage ≥T3a cancer, it still remains a valuable tool with a high specificity and thus high true positive rate for non-organ-confined disease, and should remain to be used in concert with mpMRI. Moving forward, novel strategies to further optimise mpMRI interpretation should be explored to decrease false positive stage ≥T3a test results and thus improve its prognostic value. Areas of opportunity include the reporting of the likelihood of extraprostatic extension (EPE) by using a 5-point Likert scale and standardization of the degree of EPE when definite EPE on mpMRI is established. 5–8 In addition, future studies should focus on evaluating whether local staging and risk stratification assessed by mpMRI improves oncological as well as patient-reported outcomes. Association between nerve sparing and positive surgical margins In Chapter 5 we report that side-specific nerve sparing during robot-assisted radical prostatectomy (RARP) was associated with a 40% increased odds of ipsilateral positive margins versus non-nerve sparing. Reason this association was not found in the majority of previously performed studies on this subject could be explained by insufficient adjustment for (side-specific) confounding factors. 9,10 Although these results can contribute to patient counselling and indication for nerve sparing, the study has some limitations. The retrospective nature of our study, including the performance of nerve sparing based on patient selection, is not the most ideal study design to evaluate this issue. To further evaluate the association, prospective randomised trials are needed wherein patients are randomised into nerve sparing versus non-nerve sparing. However, this design may not be justified from an ethical perspective as retaining urinary continence and erectile function is withheld in those randomised into the non-nerve sparing group. In addition to revealing the association between nerve sparing and risk of positive margins, our study led to the identification of other significant predictors of positive margins including presence of EPE on mpMRI and surgeon. To further improve the safety of nerve sparing surgery and thus improving outcomes for patients, quality improvement initiatives should focus on surgical training and surgical outcome feedback programmes, creating an environment wherein surgeons evaluate their procedures and learn from each other. Moreover, clinicians should focus on optimising their diagnostic and staging modalities. Local multi-disciplinary quality improvement programmes involving urologists, pathologists and radiologists can improve mpMRI reading and interpretation, further enhancing the detection and exclusion of EPE on pre-operative MRI enabling optimal preoperative surgical planning. Incorporating MRI information into clinical prediction models The main finding of this section is that incorporation of mpMRI information into preoperative prostate cancer nomograms positively impacts their predictive accuracy