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Prostate Cancer: Localized: Surgical Therapy III (MP50): Moderated Poster 50: Sunday, September 12, 2021

MP50-13 REIMAGINING PELVIC LYMPH NODE DISSECTION DURING RADICAL PROSTATECTOMY: INSIGHTS FROM A LARGE SERIES OF FLUORESCENCE-GUIDED PROCEDURES

Claps, Francesco; Ramirez-Backhaus, Miguel; Mascaros, Juan Manuel; Gomez-Ferrer, Alvaro; Marenco, Jose; Collado-Serra, Argimiro; Casanova, Juan; Calatrava, Ana; Trombetta, Carlo; Rubio-Briones, Jose

doi: 10.1097/JU.0000000000002076.13
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INTRODUCTION AND OBJECTIVE:

Current standard imaging procedures have limited ability to predict lymph node metastases (LNMs) in clinically localized prostate cancer (PCa) and extended pelvic lymph node dissection (ePLND) during radical prostatectomy (RP) remains the most accurate staging procedure. Nowadays the optimal extent and the oncological benefits of ePLND remains an area of controversy. Previous reports demonstrated the reliability of Indocyanine Green (ICG) as non-radioactive tracer able to drive a sentinel lymph node (SLN) mapping in patients undergoing RP. The aim of this study was to describe the anatomical location of both SLNs and LNMs through the ICG roadmap within a large series of fluorescence-guided procedures.

METHODS:

Data about 295 consecutive patients who underwent laparoscopic RP with ICG-guided SLNs mapping at our Department were prospectively evaluated. Location of SNLs was intraoperatively labelled using a predefined template. Lymph node density (LND) was defined as the ratio between the number of positive LNs and the total number of resected LNs per region of interest. To our knowledge this study shows anatomical data about the largest cohort of patients underwent ICG-guided SLN mapping.

RESULTS:

Overall, median age of patients was 64.5 years with a median PSA of 6.7 ng/ml. Extracapsular disease occurred in 140 (47.9%) patients. Fluorescent LNs were successfully identified in all patients and a total of 2058 SLNs were analyzed. A median of 6 (IQR, 3 - 8) SLNs were detected per patient. LNMs was confirmed in 66 (22.4%) patients harboring a total of 127 (6.2%) positive LNs. Percentages of SNLs retrieved per area were 25.5%, 30.4%, 27.7%, 8.7%, and 7.6% in obturator, internal, external, common iliac and presacral region, respectively. LND was significantly higher in the internal iliac region (7.2%, p=0.01). Density analysis demonstrated that more than 66.7% of SLNs were located in a junctional area including the triangle of Marcille, the proximal portion of the internal iliac route and the cranial segment of the external iliac branch. This very area harbored the higher rate of LNMs (71.7%).

CONCLUSIONS:

This pathological mapping study demonstrated a hierarchic pattern of both ICG lymphatic spread and LNMs distribution. Most of the SLNs and LNMs were found at a key junctional crossroad. This complex anatomical interplay included the triangle of Marcille, the proximal portion of the internal iliac route and the cranial segment of the external iliac branch representing a crucial hub to ascend to the common iliac region. Surgical efforts have to be focused on the dissection of this area whereas the removal of the LNs sited laterally and distally should be safely avoided, particularly when fluorescence is not noticed.

Source of Funding:

None

© 2021 by American Urological Association Education and Research, Inc.