Extended pelvic lymphadenectomy for prostate cancer: should the Cloquet's nodes dissection be considered only an option?

BACKGROUND: The aim of this study was to assess the anatomical prevalence and secondary involvement of Cloquet's nodes in patients undergoing robotic radical prostatectomy (RRP) and extended pelvic lymph node dissection (ePLND) for prostate cancer (PCa).

METHODS: RRP and ePLND were performed by two expert surgeons (WA and VDM). Data were prospectively collected and retrospectively analyzed. Dissected pelvic lymph nodes were sampled according to an anatomical template as follows: external iliac, obturator, Marcille's, and Cloquet's. Node packages were sent to the dedicated pathologist separately. Baseline characteristics, perioperative and pathological outcomes were analyzed.

RESULTS: Between January 2014 and December 2017 a total of 258 patients were evaluated. In aggregate 247 out of 258 patients (95.7%) presented at least a lymph node in the in the Cloquet's fossa tissue and 105 (40.6%) had more than one node. Patients with multiple nodes in Cloquet fossa presented higher median lymph node amount (27 vs. 33; P<0.0001). 13.5% of patients had lymph node invasion Pathological evaluation of the Cloquet's nodes showed metastatic PCa in 3 out of 35 (8.6%) pN+ patients. No differences were found when patients with metastatic Cloquet's nodes were compared with the pN+ population in terms of demographics, PSA, D'Amico classification, biopsy and pathological Gleason Grouping, clinical and pathological stage and complications.

CONCLUSIONS: To the best of our knowledge this is the first study that analyses specifically the quantitative prevalence of Cloquet's nodes and the incidence of malignancy involvement in patients undergoing RRP and ePLND for PCa. The occurrence of multiple lymph nodes in the Cloquet fossa is a rare event. Our series showed that Cloquet involvement seems to be associated with multiple nodes cohabitation and contemporarily multiple lymph node metastases in other template locations. Related morbidity rate is sporadic and cannot justify the Cloquet preservation. Wider series are required to comprehend predictor factors of Cloquet nodes involvement. Until then the Cloquet lymphadenectomy would be recommended and should not be an option.