Comparison of Real-Time Fluorescent Indocyanine Green and (99m)Tc-Nanocolloid Radiotracer Navigation in Sentinel Lymph Node Biopsy of Penile Cancer.

Introduction: The aim of this study was to compare lymphatic drainage patterns detected with fluorescent dye indocyanine green (ICG) with the lymphatic drainage patterns detected with radiotracer (99m)Tc-nanocolloid in dynamic sentinel node biopsy (DSNB) procedures.

Patients And Methods: Fourteen patients with penile cancer and no palpable lymph nodes were included prospectively for DSNB. First, on the day of surgery (99m)Tc-nanocolloid was injected at the lesion site. Then, single photon emission computed tomography (SPECT) lymphoscintigraphy was performed. ICG was injected in the same manner as the radiotracer just before the surgery. In all cases partial penectomy and DSNB were performed. Sentinel lymph nodes (SLNs) were localized intraoperatively using the gamma-ray detection probe for radiocolloid and near infrared fluorescence (NIRF) camera for ICG.

Results: Transcutaneously, lymphatic nodes were identified in all 14 patients using the gamma probe and in 10 patients using the NIRF camera. After skin incision, fluorescent nodes were observed using the NIRF camera in the remaining 4 patients. The examination led to identification of 32 SLNs in total using technetium and ICG and additionally 3 more nodes visible only using ICG. All SLNs found using SPECT were also fluorescent. In 3 patients ICG enabled only approximate localization of the SLNs. Of 35 SLNs, 30 were negative and 4 were positive for metastasis.

Conclusion: Our analysis of the effectiveness of ICG compared with radiocolloid in the DSNB for penile cancer indicates that they are comparable with some specific advantages and disadvantages. These findings must be studied further in a larger group of patients.