Presentation Authors: Lauwers Nathalie, Genk, Belgium, Filip Claus, Steven Joniau, Maarten Albersen, Vanhoutte Els, Liesbeth Dewever, Raymond Oyen, Lisa Moris*, Cindy Mai, Uros Milenkovic, Wouter Everarts, Leuven, Belgium
Introduction: Current evidence strongly supports the use of multiparametric magnetic resonance imaging (mpMRI) pre-biopsy in men with a suspicion of prostate cancer (PCa) based on elevated PSA. Nevertheless, concerns remain about the negative predictive value of MRI and the potential to miss significant cancers when withholding patients with a negative mpMRI from undergoing prostate biopsies.The objective of this study is to evaluate the clinical outcomes of men with a negative mpMRI (nMRI) after at least 5-years follow-up at our institution.
Methods: We retrospectively analysed a database of 1741 patients that received an mpMRI-scan in our institution between 2006-2013. All patients (n=297) with a negative MRI and a minimum of 5-year follow-up after this MRI were included in our study. For analysis patients were divided in to two groups: biopsy-naÃ¯ve patients (group A) and patients with previous negative biopsy (group B).Kaplan-Meier survival analysis was performed to determine 5-year csPCa and any-grade PCa diagnosis-free survival probabilities in both groups. Multivariate Cox regression analysis was performed to identify predictors of csPCa using the age, previous negative biopsies and PSA-density. A p-value of < 0,05 was considered statistically significant. Both p-values were corrected for multiple testing using the Bonferroni method.
Results: Of all 297 men with nMRI 138 fitted the inclusion criteria. Of these patients 60 were biopsy naÃ¯ve (group A) and 78 had previous negative biopsies (groups B). The overall prevalence of clinically significant prostate cancer (csPCA) in patients with nMRI was 12% in our study. Any-grade PCa diagnosis-free survival probability at 60 months was 91% and 97% for group A and group B respectively (log rank p=0,08). The csPCa diagnosis-free survival at 60 months was 91% for group A and 99% for group B (log rank p < 0,001).Multivariate Cox regression showed that higher PSA-density (PSAD, ng/ml2) is an independent predictor of subsequent csPCa in men with nMRI (p < 0,05, HR 7,3). Previous negative biopsy predicts a lower risk of csPCa diagnosis probability in patients with negative MRI (p < 0,05, HR 0,14). Study limitations include the small study population and its retrospective design.
Conclusions: Our study showed that nMRI is a reliable tool to predict the absence of clinically significant PCA at 5 years, even more so in patients with previous negative biopsy. In patients without a previous biopsy and a high PSA-density, systematic biopsies should be considered, despite an nMRI.