Indocyanine green fluorescence-guided sentinel lymph node identification in urologic cancers: a systematic review and meta-analysis

INTRODUCTION: To date, bilateral pelvic lymph node dissection (PLND) represents the most accurate and reliable staging procedure for the detection of lymph node invasion in prostate cancer and bladder cancer. However, the procedure is not devoid of complications. In this field, Indocyanine green fluorescence-guided sentinel lymph node (SLN) identification is an emerging and promising technique, as accurate staging of urologic cancer could be enhanced by a thorough evaluation of the sentinel lymph nodes. Aim of the present review is to analyze available evidence and perform a metanalysis on ICG-guided SLN detection for urologic malignancies. EVIDENCE ACQUISITION: A systematic review to assess the clinical value of Indocyanine green for the identification of sentinel lymphatic drainage for bladder, prostate, kidney and penile cancers was undertaken, with a meta-analysis to generate pooled detection rate concerning patients (clinical sensitivity) and nodes basin (technical sensitivity) separately. Studies reporting on the use of Indocyanine green for the detection of SLNs from the bladder, prostate and penile cancers were included. EVIDENCE SYNTHESIS: A total of 10 clinical trials were included. Using the fixed effects model and the random effects model, the pooled patient detection rates and their 95% confidence intervals (95% CI) were 0.88 (0.82-0.92) and 0.92 (0.84-0.96), respectively. The pooled nodes detection rates were 0.71 (95% CI: 0.68-0.74) using the fixed effect model and 0.75 (95% CI: 0.56-0.87) using the random effect model. Significant heterogeneities existed among studies for patients and for nodes (I-2=0.66, P<0.001 and I-2=0.96, P<0.001, respectively). Significant publication bias was found in patient detection rate (P<0.001) and in nodes detection rate (P<0.001). CONCLUSIONS: SLN mapping in bladder and prostate cancer is a method with a high detection rate, although its specificity to predict LN invasion remains poor. Large, well-constructed trails are needed to assess the impact of ICG-fluorescence guided SLN dissection on uro-oncologic surgery.