Page 26 - Fluorescence-guided cancer surgery

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Chapter 2
utilized indocyanine green (ICG) as the lymphatic tracer. However, the use of ICG resulted in detection of more uorescent lymph nodes per patient than expected due to migration through the SLN to second tier nodes. Consequently, resection and pathological assessment of multiple nodes was still needed. Adsorption of ICG to a nanocolloid (ICG:Nanocoll) increases its hydrodynamic diameter, which may result in better retention of the lymphatic tracer in the SLN, and thereby staining less second-tier nodes. This results in intraoperative identi cation of true SLNs, and avoids analyzing non-SLNs during pathological assessment for tumor-status of the SLN. This principle was already successfully described for breast cancer16 and skin melanoma17.
The aim of this study was to investigate feasibility of ICG adsorbed to nanocolloid as a lymphatic tracer for the intraoperative detection of the SLN in gastric cancer patients with di erent pT stages, and to determine the prognostic utility of the detected SLN.
MATERIALS AND METHODS
Tracer preparation
ICG:Nanocoll was prepared by diluting 25mg ICG (Pulsion Medical Systems, Munich, Germany) in 5ml water and diluting 0.5mg Nanocoll (GE Healthcare, Eindhoven, the Netherlands) in 3ml saline. Portions of these solutions were mixed to obtain 1.6ml ICG:Nanocoll containing 0.05mg ICG and 0.1mg Nanocoll. Preparation was performed in the operating room, following preparation instructions of the institutional pharmacist.
Clinical trial
The trial was approved by the Medical Ethics Committee of the Leiden University Medical Center and was performed in accordance with the ethical standards of the Helsinki Declaration of 1975. Registration within the Netherlands Trial Register was performed (NTR4280).
Twenty-six patients with di erent T stages of gastric cancer, planned for a partial or total gastrectomy, were included between February 2013 and March 2015. Patients underwent standard-of-care preoperative imaging using a Computed Tomography (CT) scan. No standard endoscopic ultrasound or staging laparoscopy was performed. All procedures were performed by surgeons with broad experience in gastric cancer surgery.