In this study, the authors ask a slightly reversed question – in men undergoing targeted biopsy alone, is there an added benefit to systematic biopsy? Adding systematic cores to MRI-targeted biopsy might improve the detection of csPCa - but, the implications of adding systematic cores in predicting adverse pathology in men undergoing radical prostatectomy (RP) are still unknown. I would argue that isn’t necessarily the case – we know the implications of doing a combined systematic + targeted biopsy, systematic alone and targeted alone from numerous studies. In general, from most of the large randomized trials (primarily out of the UK), there is some additional benefit to obtaining systematic cores in addition to targeted cores.
However, in certain settings, many centers are now doing targeted only biopsies. In this study, the authors assessed 614 patients who underwent MRI-targeted biopsy and RP between 2016 and 2018 at five international referral centers. All patients received concomitant systematic biopsy at the time of targeted biopsy. The D’Amico risk groups and the rate of pathological upgrading were assessed considering grade group (GG) at targeted biopsy and after adding information from the systematic biopsy. A logistic regression model assessed the impact of MRI-targeted biopsy parameters (PSA, prostate volume, grade group at target biopsy, clinical stage and the diameter of the mpMRI lesion) on the risk of upgrading. Then, a model that included also information on clinically significant PCa outside the index lesion, the number of random positive and total cores were developed. The difference between these models was assessed using area under the curve (AUC) analyses.
Median PSA was 7.8ng/ml. Targeted biopsy GG was 1, 2, 3, and >=4 in 86 (13%), 325 (49.3%), 138 (20.9%) and 110 (17%) patients – but when considering systematic cores as well, biopsy GG was 1, 2, 3, and >=4 in 60 (9%), 333 (50%), 145 (22%) and 121 (18%) men; slightly higher in the GG 3 and 4-5 groups. Overall, 86 (13.1%), 445 (67%) and 128 (19%) patients had low-, intermediate- and high-risk disease at targeted biopsy – when including systematic biopsy, 42 (6.4%), 451 (68%) and 166 (25%) patients had low-, intermediate- and high-risk. This is summarized below:
In terms of reclassification, as you can see above, with systematic biopsies, an additional 6% were classified as high-risk, and an additional 5% were classified as GG3-5 disease.
More importantly, the rate of upgrading from biopsy GG to final RP GG decreased when accounting for systematic biopsies: 32% with targeted biopsies alone to 26% when including information from systematic biopsy (P=0.04). Significant disease at systematic biopsy and a higher number of systematic cores taken were associated with a reduced risk of upgrading (all p<0.01).
When comparing the models with and without the systematic biopsy info, the discrimination of a model predicting upgrading including systematic biopsy information was higher compared to including targeted biopsy only (AUC: 75 vs. 72%). Similar results were found in models predicting ECE and SVI.
Based on this info, and along with the data already published, it would appear that continuing to assess systematic biopsies at the time of targeted biopsy allows for better accurate staging of patients – their data reinforces the need for accurate systematic biopsy sampling to improve accuracy for tumor grading and to optimize patient selection for active surveillance or focal therapies.
Presented by: Giorgio Gandaglia, MD, Cancer Prognostic and Health Outcomes Unit, Université de Montréal, Montréal, Quebec, Canada
Co-authors: Guillaume Ploussard, Massimo Valerio, Agostino Mattei, Cristian Fiori, Nicola Fossati, Armando Stabile, Jean-Baptiste Beauval, Bernard Malavaud, Mathieu Roumiguié, Daniele Robesti, Paolo Dell'Oglio, Federico Dehò, Umberto Capitanio, Marco Moschini, Stefania Zamboni, Arnas Rakauskas, Francesco De Cobelli, Francesco Porpiglia, Francesco Montorsi, Alberto Briganti
Written by: Thenappan Chandrasekar, MD (Clinical Instructor, Thomas Jefferson University) (twitter: @tchandra_uromd, @JEFFUrology) at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois