EMUC 2020: Hybrid ICG - 99mTc - Nanocolloid, on the Road Towards Becoming the New Standard for Sentinel Node Biopsy in Penile Cancer

(UroToday.com) In a talk presented in the Oral Presentations session of the 12th European Multidisciplinary Congress on Urological Cancers (EMUC), Dr. De Vries presented on the role of indocyanine green (ICG) as a tracer in sentinel node biopsy for penile cancer.

To date, sentinel lymph node biopsy in penile cancer has typically been guided with the use of 99m-TC-nanocolloid and blue dye. The authors postulated that the use of ICG-99m-TC-nanocolloid may improve localization intra-operatively due to the ability to use combined radioactive and fluorescence guidance.

To assess this, they included 400 patients with T1G2N0 penile cancer who were undergoing sentinel lymph node biopsy and management of their primary penile lesion. Sentinel nodes were identified based on pre-operative lymphoscintigraphy and SPECT/CT after peritumoral injection of ICG-99mTc-nanocolloid. In a subset of 266 (of 400 )patients, blue dye was intra-operatively. The investigators used a combination of gamma tracing, visual identification of blue dye, and near-infrared fluorescence imaging intra-operatively to identify sentinel lymph nodes. With an individual patient unit of analysis, the authors compared intra-operative sentinel node identification rates using radio and fluorescence guidance. Among the subset who also received blue dye, this approach was further compared to fluorescence identification rates.

Among the 400 included patients, 740 unilateral groins were examined. 100% (n=1163) of pre-operatively identified sentinel lymph nodes were successfully identified intraoperatively. 98% of that would be detected with gamma tracing and 96% with fluorescence localization. Among the excised sentinel nodes, 95 contained tumors, all of which were able to be identified based on both radioactive and fluorescent signals. Comparing blue dye with the use of fluorescence localization, the authors found a substantially higher rate of sentinel node identification using fluorescent signals (95.3%) compared with blue dye (56.1%). Among those nodes which were positive for tumor involvement, all were identifiable with fluorescence imaging while 84% would be identified using blue bye.

The authors conclude that ICG-99m-TC-nanocolloid is a reliable tracer and the use of the fluorescence outperformed blue dye. The identification of tumor-involved lymph nodes was similar to the use of a fluorescent approach or gamma tracing.

Presented by: Hielke-Martijn de Vries, PhD Candidate, bij Leiden University Medical Center Amsterdam, North Holland, Netherlands

Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center Contact: @WallisCJD at the 12th European Multidisciplinary Congress on Urological Cancers (EMUC) (#EMUC20 ), November 13th - 14th, 2020
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