Presentation Authors: Alexandar Blazevski*, Matthijis Scheltema, Brian Yuen, Thomas Cusick, Anne-Maree Haynes, Phillip Stricker, Darlinghurst, Australia
Introduction: The utilisation of focal therapy for prostate cancer (PCa) is increasing worldwide. There is no agreed protocol on how to monitor patients post focal therapy treatment however many institutions utilise multiparametric magnetic resonance imaging (mpMRI) to detect residual or recurrent PCa. The objective of this study is to determine the diagnostic accuracy of mpMRI to detect residual PCa following focal therapy with irreversible electroporation (IRE).
Methods: Between February 2013 and September 2018, 170 patients consented and underwent primary IRE treatment. 102 of these patients were included for analysis after undergoing a follow-up mpMRI at 6 months and a transperineal template mapping biopsy at 12 months. PI-RADS v2 was used to report outfield region of interest (ROI) recurrence while a binary outcome (suspicious v nonsuspicious) was used for the infield ablative zone. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of mpMRI was calculated in patients with Gleason â‰¥ 3 + 4, and Gleason â‰¥ 3 + 3 with a maximum core length â‰¥ 4 mm on follow up biopsy. The diagnostic accuracy was calcuated for infield ROI, outfield ROI, as well as the whole gland.
Results: Sensitivity, specificity, PPV and NPV of infield ROI was 40%, 98%, 67% and 94%, whilst outfield ROI was 58%, 93%, 69% and 90% respectively. For whole-gland this was 56%, 89%, 60% and 86%.
Conclusions: Our data shows that follow up mpMRI is able to rule out residual PCa in both the infield and outfield. However, given that 14% of residual PCa is missed by mpMRI, repeat prostate biopsies are still required in patients following focal therapy. Limitations of this study are the low incidence of recurrence in our cohort and the retrospective design of the study.