A Multicentric Study on Accurate Grading of Prostate Cancer with Systematic and MRI/US Fusion Targeted Biopsies: Comparison with Final Histopathology after Radical Prostatectomy - Beyond the Abstract

Several large studies have shown a limited correlation between systematic biopsies and final histopathologic outcomes with discordance values reaching up to 50%, disease upgrading and downgrading in more than 30% and 20% of cases respectively1-2. Gleason score remains one of the most important prognostic factors and an essential component for determining the best treatment strategy.  Recently, multiparametric magnetic resonance imaging (mpMRI) has emerged as a new tool for early detection of prostate cancer before reverting to traditional biopsies in suspected cases and recent studies confirm its high sensitivity especially for clinically significant cancer3. Although researchers have sought to establish a difference in term of significant cancer detection between systematic and targeted biopsies using data provided by mpMRI analysis, we believe that histopathologic concordance is of utmost importance as it might imply a change in the therapeutic attitude4.

In this manuscript, we compared the histopathologic concordance with radical prostatectomy between systematic (SB), targeted (TB) biopsies (MRI/US image fusion using Koelis® device) and the combination of both (systematic and targeted biopsies together, SB + TB). We analyzed 443 patients who underwent radical prostatectomy after systematic and targeted biopsies. For ISUP grade group ≥ 2 (Gleason score ≥ 7 (3+4)) at surgery, a significant difference was found between SB group and SB + TB group for upgrading, downgrading and concordance (p < 0.001), between TB group and SB + TB group (p < 0.001), between SB group and TB group (only for upgrading and concordance, p < 0.001). A post hoc subgroup analysis including only biopsy-naïve patients showed similar results (Figure 1a-b-c). Finally, multivariable analysis revealed that previous biopsy (OR = 0.6, 95% CI (0.4 – 0.9) p = 0.01) and number of cores taken (OR = 1.2, 95% CI (1.1 – 1.3) p = 0.004) were independently associated with histopathological concordance.

Figure 1a. Histopathological concordance with the final specimen, overall ISUP grade.
Figure 1a. Histopathological concordance with final specimen, overall ISUP grade.png
Figure 1b. Histopathological concordance with the final specimen, ISUP ≥ 2.
Figure 1b. Histopathological concordance with final specimen, ISUP ≥ 2.png
Figure 1c. Histopathological concordance with the final specimen, ISUP ≥ 2 (biopsy-naïve patients).
Figure 1c. Histopathological concordance with final specimen, ISUP ≥ 2 (biopsy-naïve patients).png


To conclude, our data are in line with current literature and emphasize the importance of targeted biopsies. MRI/US image fusion and systematic biopsies were found to be complementary, significantly increasing concordance with final histopathology and causing a significant decrease in disease upgrading. Combining these two techniques may aid in tailoring the adequate treatment for each patient. In concordance with the results of the PRECISION, MRIfirst and 4M studies, we believe in the necessity of performing targeted biopsies to be able to evaluate tumors more accurately.

Written by: Romain Diamand, MD, Department of Urology, Jules Bordet Institute, Université Libre de Bruxelles, Brussels, Belgium

References:
1. Cohen MS, Hanley RS, Kurteva T, Ruthazer R, Silverman ML, Sorcini A, et al. Comparing the Gleason Prostate Biopsy and Gleason Prostatectomy Grading System: The Lahey Clinic Medical Center Experience and an International Meta-Analysis. Eur Urol. 2008;54(2):371–81.
2. King CR, Long JP. Prostate biopsy grading errors: A sampling problem? Int J Cancer. 2000;90(6):326–30
3. Ahmed HU, El-Shater Bosaily A, Brown LC, Gabe R, Kaplan R, Parmar MK, et al. Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): a paired validating confirmatory study. Lancet. 2017;389(10071):815–22.
4. Kasivisvanathan V, Rannikko AS, Borghi M, Panebianco V, Mynderse LA, Vaarala MH, et al. MRI-Targeted or Standard Biopsy for Prostate-Cancer Diagnosis. N Engl J Med [Internet]. 2018;NEJMoa1801993. Available from: http://www.nejm.org/doi/10.1056/NEJMoa1801993 

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