Sentinel Lymph Node Procedure in Pediatric Patients with Melanoma, Squamous Cell Carcinoma, or Sarcoma Using Near-Infrared Fluorescence Imaging with Indocyanine Green: A Feasibility Trial

Abstract

Background: Standard sentinel lymph node procedure (SNP) in pediatric cancer consists of a preoperative injection with 99mtechnetium nanocolloid in combination with an optional intraoperative injection with blue dye. However, blue dye has disadvantages, and the detection rate is low, with only 60% of sentinel lymph nodes (SLNs) staining blue. In adult oncology, fluorescence imaging using indocyanine green (ICG) has been shown to be a safe and accurate method for visual detection of SLNs, with a higher sensitivity (up to 97%) compared with blue dye. Therefore, our aim is to determine the feasibility of the addition of ICG to 99mtechnetium nanocolloid (ICG–TC) for visual detection of SLN in pediatric patients. Methods: A total of 15 pediatric patients with melanoma, squamous cell carcinoma, and sarcoma were prospectively included. Preoperatively, patients were injected with ICG–TC and imaging with lymphoscintigraphy and single-photon emission computed tomography– computed tomography was performed. Intraoperatively, SLN was detected with fluorescence and the gamma probe. Postoperatively, fluorescence was quantified by tumor-to-background ratio (TBR) and surgeons evaluated the use of ICG using a standardized questionnaire. Results: In 10/15 (67%) patients, SLNs were visible transcutaneously. Of all intraoperatively detected SLNs, 35/37 (95%) were fluorescent and 37/37 (100%) were radioactive. Furthermore, ICG–TC led to the identification of six additional SLNs as compared with preoperative imaging. The median TBR in vivo was 6.5 (IQR 5.3). The surgical evaluation showed that ICG assisted in SLN detection and was easy to use. Conclusions: ICG–TC for the SNP is a feasible procedure in pediatric patients. It showed an accurate detection rate, was helpful for visual guidance, and no adverse events occurred.