Hybrid Indocyanine Green-^99mTc-nanocolloid for Single-photon Emission Computed Tomography and Combined Radio- and Fluorescence-guided Sentinel Node Biopsy in Penile Cancer: Results of 740 Inguinal Basins Assessed at a Single Institution.

Abstract

RESULTS AND LIMITATIONS

In total, 740 groins were assessed. No tracer-related (allergic) reactions were reported. All preoperatively defined SNs (n=1163) were localised intraoperatively. Of all excised SNs, 98% were detectable with gamma probe and 96% were visible with fluorescence imaging. In the analysis of the patients who received ICG-^99mTc-nanocolloid and blue dye, fluorescence imaging yielded a 39% higher SN detection rate than blue dye (95% confidence interval 36-43%, p<0.001). Of the SNs that were tumour positive, 100% were intraoperatively visualised by fluorescence imaging, whereas merely 84% of the positive nodes stained blue.

PATIENT SUMMARY

Hybrid indocyanine green (ICG)-^99mTc-nanocolloid is a safe and reliable sentinel node (SN) tracer, as established in this large series of 400 penile cancer patients (740 groins). It enables accurate pre- and intraoperative SN identification and significantly improves SN detection rate compared with blue dye, without staining the surgical field or the need for an additional injection.

CONCLUSIONS

This study confirms that ICG-^99mTc-nanocolloid is a reliable SN tracer for PeCa that significantly improves optical SN detection over blue dye.

BACKGROUND

Sentinel node (SN) biopsy in penile cancer (PeCa) is typically performed using ^99mTc-nanocolloid and blue dye. Recent reports suggested that the hybrid (radioactive and fluorescent) tracer indocyanine green (ICG)-^99mTc-nanocolloid may improve intraoperative optical SN identification.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

All patients (n=400, 740 groins) received ICG-^99mTc-nanocolloid. Intraoperative SN identification rates were retrospectively evaluated. In those patients who received ICG-^99mTc-nanocolloid and blue dye (n=266, 492 groins), SN visualisation rates were compared using the McNemar test.

DESIGN, SETTING, AND PARTICIPANTS

A total of 400 ≥T1G2N0 PeCa patients were staged with SN biopsy at a single European centre. SNs were preoperatively identified with lymphoscintigraphy and single-photon emission computed tomography. Intraoperatively, SNs were detected via gamma tracing, blue staining, and fluorescence imaging.

OBJECTIVE

The current study aimed to confirm the reliability of ICG-^99mTc-nanocolloid and to assess whether blue dye is still of added value.