Free-indocyanine green-guided pelvic lymph node dissection during radical prostatectomy

Abstract

Introduction and objectives: Extended Pelvic Lymph Node Dissection (ePLND) remains the most accurate technique for the detection of occult lymph node metastases (LNMs) in prostate cancer (CaP) patients. Here we aim to examine whether free-Indocyanine Green (F-ICG) could accurately assess the pathological nodal (pN) status in CaP patients during real-time lymphangiography as a potential replacement for ePLND.

Materials and methods: 219 consecutive patients undergoing F-ICG-guided PLND, ePLND and radical prostatectomy (RP) for clinical-localized CaPwere included in this prospective single-center study. The pathological outcomes of F-ICG-guided PLND were compared to confirmatory ePLND. Parameters of a binary diagnostic test for the proper classification of the pN status of patients ('per-patient' analysis) and for the probability of detecting all the metastatic LNs ('per-node' analysis) were calculated. Outcome measures were prevalence, accuracy (Acc), sensitivity (Se), negative predictive value (NPV), and likelihood ratio of a negative F-ICG-guided PLND test result [LR(-)].

Results: F-ICG-guided PLND successfully visualized LNs in all procedures with no adverse events. The overall per-patient F-ICG staging Acc was 97.7%, Se was 91.4%, with a NPV of 97.0%, and LR(-) of 8.6%. At the overall per-node level, 4,780 LNs were removed and 1,535 (32.1%) were fluorescent in vivo. F-ICG-guided PLND identified LNMs with a Se of 63.4%.

Conclusions: This study confirms that F-ICG-guided lymphangiography correctly staged almost 98% of patients. The high per-patient NPV suggested that avoiding ePLND is safe for most patients when F-ICG stained nodes were pN0. Thus, more conservative approaches might minimise perioperative morbidity during LNMs diagnosis in selected patients.

Keywords: Extended pelvic lymph node dissection; Fluorescence; Indocyanine green; Prostate cancer; Sentinel lymph node biopsy.