Is the Recommendation of a Pelvic Lymphadenectomy in Conjunction with Radical Prostatectomy in Prostate Cancer Patients Justified? Report from a Multidisciplinary Expert Panel Meeting.

Introduction: Pelvic lymphadenectomy (pLA) in prostate cancer (PCa) is one of the most common uro-oncologic surgical procedures. An increased complication rate is accompanied by unproven oncologic benefit. Extent of pLA and mechanisms of metastasis are discussed controversially. We aimed to explore evidence and knowledge gaps in pLA and mechanisms of metastasis in PCa and to develop further steps to clarify oncologic benefits through an expert panel.

Methods: A multidisciplinary expert meeting was initiated, compiling available facts on pLA and mechanisms of metastasis in PCa. Questions and hypotheses were formulated. The resulting protocol was modeled on priority and consistency in four anonymized voting rounds using the Delphi method (March 2018-June 2018).

Results: The oncologic benefit of pLA in PCa is still unclear. Results of randomized trials (RCTs) are pending. Extent and techniques of pLA are differently applied and inconsistently recommended by the guidelines as well as the indication for pLA. Different growth rates for the primaries and metastases and different survival curves for lymph node and organ metastasis at diagnosis argue against metastasis originating from positive nodes. However, results from clinical and basic research support this opportunity in PCa.

Conclusions: The RCTs required to clarify the estimated low oncologic benefit of pLA prove to be difficult because of the great effort (e.g., high case number). Establishing a network of treatment centers for implementation of high-quality cohort studies could be an alternative approach. Future studies with larger panels and international participants based on the presented feasibility should be launched to set this process in motion. Until valid data are available, benefits and harms of pLA should be weighted under consideration of low-invasive techniques (e.g., sentinel pLA).