Fluorescence-enhanced Robotic Radical Prostatectomy Using Real-time Lymphangiography and Tissue Marking with Percutaneous Injection of Unconjugated Indocyanine Green: The Initial Clinical Experience in 50 Patients

BackgroundPilot studies have demonstrated the utility of indocyanine green (ICG) sentinel lymphadenectomy for prostate cancer. Prior work has used ICG with radiocontrast agents injected at a separate procedure and relied on assistant-controlled fluorescence systems, making the technique costly and cumbersome.ObjectiveTo describe the initial optimization and feasibility of fluorescence-enhanced robotic radical prostatectomy (FERRP) using real-time injection of ICG for tissue marking and identification of sentinel lymphatic drainage visualized by a fully integrated surgeon-controlled system.Design, setting, and participantsPatients with clinically localized prostate cancer at a tertiary referral center were offered FERRP. Ten patients participated in a pilot arm in which ICG dosing and injection technique were optimized. Fifty consecutive patients then underwent FERRP.Surgical procedureAfter development of the space of Retzius, 0.4 ml of a 2.5 mg/ml ICG solution were injected into each lobe of the prostate using a robotically guided percutaneous needle. After ICG was allowed to travel through the pelvic lymphatics, lymphadenectomy was performed from the endopelvic fascia to the aortic bifurcation.Outcome measurements and statistical analysisParameters describing the time course of tissue fluorescence and pelvic lymphangiography were systematically recorded. Lymphatic packets containing fluorescent nodes were considered sentinel.Results and limitationsPercutaneous, robotic-guided ICG injection proved superior to cystoscope or transrectal delivery. Tissue marking was achieved in all patients, positively identifying the prostate with uniform fluorescence relative to the obturator nerve, seminal vesicles, vas deferens, and neurovascular pedicles at a mean time of 10 min postinjection. Sentinel nodes were identified in 76% of patients at a mean time of 30 min postinjection and had 100% sensitivity, 75.4% specificity, 14.6% positive predictive value, and 100% negative predictive value for the detection of nodal metastasis.ConclusionsFERRP is safe, feasible, and allows for reliable prostate tissue marking and identification of sentinel lymphatic drainage in the majority of patients. ICG sentinel nodes are highly sensitive but relatively nonspecific for the detection of nodal metastasis.