Pelvic lymph node dissection using indocyanine green fluorescence lymphangiography in robotic assisted radical prostatectomy for non-lymph node or distant metastasis prostate cancer patients

Purpose: The utility of indocyanine green dye (ICG) has evolved significantly to the robotic operations including Robotic Assisted Radical Prostatectomy (RARP). The technology can help the identification of sentinel lymphatic drainage in lymphadenectomy for the majority of prostate cancer (PCa) patients. We describe the potential indications of ICG for lymphadenectomy assistant in PCa patients without lymph node or distant metastasis. Materials and Methods: We prospectively analyzed PCa patients without lymph node or distant metastasis with clinical pathological stage T1c to T3a received RARP from November 2019 to May 2020. The clinical data and pathological data, including Gleason score, tumor volume, pathological stage, and surgical findings, were described. All lymph nodes were divided into ICG positive or negative. All patients were divided into low, moderate, and high risk according to the European Association of Urology PCa risk stratification. Results: Cystoscope-guided intraprostatic injection was performed successively in 34 localized PCa patients in this study. The mean age was 66.1 ± 7.8 years old. The patients' number of high, moderate, and low risk was 18, 10, 6. A total of 447 lymph nodes were identified. Two hundred and sixty-two lymph nodes were ICG positive and 181 lymph nodes were ICG negative. ICG positive rate higher in high risk patients 158/259 (61.0%) compare to intermediate/low risk patients 104/188 (55.3%). There was no statistic significant result, but lymph node could be identified in all ICG-positive tissues. There were 12 patients revealed higher Gleason grade group after RARP and two patients revealed lower Gleason grade group after RARP. There were 18 patients showed upgrade stage after RARP and 4 patients showed down stage after RARP. Conclusion: Cystoscope-guided intraprostatic ICG injection with fluorescence lymphangiography can help identify pelvic lymph nodes in RARP for PCa patients without lymph node or distant metastasis.