Diagnostic and therapeutic value of pelvic lymph node dissection in the fossa of Marcille in patients with clinically localized high‐risk prostate cancer: Histopathological and molecular analyses

Abstract

The optimal extent of lymph node dissection in radical prostatectomy has not been determined. Lymph nodes in the fossa of Marcille, which is an important pelvic lymphatic pathway and candidate for additional dissection, have not been evaluated at the molecular level. Here, we assessed by molecular analysis the presence of occult positive lymph nodes in the fossa of Marcille in patients with clinically localized high-risk prostate cancer. Fifty-two patients with clinically localized high-risk prostate cancer underwent pelvic lymph node dissection accompanied by robot-assisted radical prostatectomy. All nodal packets were dissected separately and grouped into right and left obturator, external and internal iliac regions (including common iliac region to ureter crossing), and fossa of Marcille. All lymph nodes were bisected and evaluated by histopathological or molecular analysis using a quantitative reverse transcription-polymerase chain reaction. The number of positive lymph nodes in the fossa of Marcille and the difference in detection rate were investigated using histopathological and molecular analyses. Perioperative complication rate and predictive factors for biochemical recurrence were evaluated. In the molecular analysis, there were seven positive lymph nodes in the fossa of Marcille in three patients, which were coexistent with positive nodes in other regions. The detection rate of positive lymph nodes was significantly higher using molecular than histopathological analysis (P < .01). Perioperative complication rate within 90 days after the operation was 25.0% and no Clavien-Dindo grade ≥3 complication was confirmed. Detection of metastasis by histopathological and molecular analysis was a significant factor related to biochemical recurrence in the Cox proportional hazards regression model. No case of positive lymph nodes in the fossa of Marcille that had skipped over other regions was confirmed. Additional lymph node dissection of fossa of Marcille did not lead to complete resection of molecularly positive lymph nodes.