AUA 2022: Topographic Description of the Site of Positive mpMRI and Impact on the Risk of Positive Surgical Margins at Robot-Assisted Nerve Sparing Radical Prostatectomy: Implications for Accurate Surgical Approaches

(UroToday.com) The 2022 American Urological Association (AUA) Annual Meeting included a session on surgical therapy of localized prostate cancer and a presentation by Dr. Francesco Barletta discussing the topographic description of the site of positive multiparametric MRI (mpMRI) and impact on the risk of positive surgical margins at robot-assisted nerve sparing radical prostatectomy. Using mpMRI may reduce the risk of positive surgical margins in men with non-palpable prostate cancer. However, its role may vary according to the location of the index lesion. Dr. Barletta and colleagues hypothesized that the site of mpMRI positivity might impact on the risk of positive surgical margins in men undergoing nerve-sparing robot-assisted radical prostatectomy.

 Overall, 307 prostate cancer patients diagnosed with mpMRI-targeted biopsy and treated with nerve-sparing robot-assisted radical prostatectomy at a referral center between 2018 and 2021 were identified. Among those, 283 had detailed information on the site of the index lesion and on the presence of extracapsular extension at mpMRI and represented the study cohort. All patients had details on the site and location of extracapsular extension and positive surgical margins (i.e., malignant cells in contact with the inked surface of the prostate) at final pathology. The proportion of positive surgical margins at the site of the index lesion (namely, concordant) and not concordant with the index lesion location was assessed using contingency tables. The chi-square compared proportions between groups. Logistic regression analyses evaluated the impact of the index lesion location on the risk of having a concordant positive surgical margin.

 In this study, the median age and PSA were 66 years (IQR 60-71) and 6.6 ng/ml (IQR 4.5-10), respectively. Overall, 5 (2%), 201 (71%) and 77 (27%) patients had grade group 1, 2-3, and 4-5, respectively. The median index lesion volume was 0.5 cc (IQR 0.4-1.4). The patient characteristics are as follows:

 

AUA2022_Barletta_1 

 

Overall, 54 (19%), 147 (52%) and 82 (29%) patients had an index lesion at the base, lateral side, and apex, respectively. Among those, 8, 17 and 6 patients had extracapsular extension at mpMRI at the base, lateral side and apex, respectively. Overall, 40 (14%) patients had positive surgical margins and the rate was 20%, 47% and 32% at the base, lateral side and apex, respectively. The site of positive surgical margins was concordant with the index lesion in 15/40 (37%) patients. When stratifying patients with positive surgical margins according to the index lesion location at mpMRI, the proportion of men with a concordant positive surgical margin was higher among those with a lesion at the base (75%) versus lateral (31%) versus apex (23%). Using multivariable analyses, an index lesion at the base had an odds ratio of 15.2 (p = 0.03) for concordant positive surgical margins in men with positive margins.

Dr. Barletta concluded his presentation by discussing the topographic description of the site of positive multiparametric MRI (mpMRI) and impact on the risk of positive surgical margins at robot-assisted nerve sparing radical prostatectomy with the following take-home messages:

  • Men with lesions located at the base have a higher risk of a positive surgical margins if located at the same site
  • Conversely, individuals with a lesion at the lateral margin or apex have a higher risk of harboring a positive surgical margin elsewhere
  • These findings should help surgeons in guiding the optimal extent of the dissection during nerve-sparing robot-assisted radical prostatectomy 

 

Presented by: Francesco Barletta, MD, IRCCS Ospedale San Raffaele, Milan, Italy

Co-Authors: Giorgio Gandaglia, Giuseppe Rosiello, Simone Scuderi, Armando Stabile, Elio Mazzone, Milano, Italy; Nicola Fossati, Andrea Gallina, Lugano, Switzerland; Emanuele Zaffuto, Umberto Capitanio, Alessandro Larcher, Milan, Italy; Andrea Salonia, Milano, Italy; Federico Deho, Varese, Italy; Pierre I. Karakiewicz, Montreal, Canada; Shahrokh F. Shariat, Vienna, Austria; Vincenzo Mirone, Napoli, Italy; Francesco Montorsi, Alberto Briganti, Milano, Italy

Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2022 American Urological Association (AUA) Annual Meeting, New Orleans, LA, Fri, May 13 – Mon, May 16, 2022.

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