P2D327: Utility of Indocyanine Green for Sentinel Lymph Node Biopsy in Pediatric Sarcoma and Melanoma

Background: Indocyanine green (ICG) is a fluorescent dye with increasing use for adult sentinel lymph node biopsy (SLNB). The utility of ICG in pediatric oncology remains understudied, with current literature detailing its limited application in tumor demarcation and resection. We aim to describe our experience using ICG for SLNB in pediatric melanoma and sarcoma and compare its utility to standard blue dye.

Methods: A retrospective review of pediatric patients with melanocytic lesions or sarcoma who underwent SLNB with technetium and ICG or blue dye from 2014-2023 at a single large academic children’s hospital was conducted. Chi-square analyses and nonparametric tests were used to compare SLNB results and outcomes between those patients who underwent biopsy using ICG versus blue dye.

Results: Twenty-four patients were included, 58.3% of whom were male (n=14), 91.7% white (n=22), with median age 13 years (range 4-21 years). The majority had a melanocytic lesion (n=22, 91.7%), and 8.3% had sarcoma (n=2). All patients received technetium, with fifteen also receiving blue dye (62.5%) and 9 receiving ICG (37.5%). There were no adverse events associated with ICG or blue dye use. There was no significant difference in median operative time between ICG and blue dye (192 min [IQR 71-235] vs 92 min [78-105], p=0.22). The median number of SLN biopsied was similar (ICG 2 [2-3] vs blue dye 3 [2-5], p=0.14); however, 100% of radioactive SLN identified with technetium were fluorescent with ICG, but only a median of 58.3% (IQR 25.0%-66.7%) of radioactive nodes were identified with blue dye (p=0.03). There was no difference in bilateral SLN detection (11.1% ICG vs 6.7% blue dye, p=0.70). [TABLE 1] Seven patients had positive SLN (29.2%), all of whom underwent subsequent completion lymph node dissection. Recurrence was noted in 2 patients (8.3%), and 1 patient died (4.2%).

Conclusion: We demonstrate that ICG-directed SLNB in pediatric melanoma and sarcoma is a safe, feasible, and effective alternative to blue dye-directed sentinel node detection. Importantly, ICG injection at the primary site does not discolor the region of the primary tumor, whereas blue dye injection will stain the primary site. Use of ICG did not add to operative time, and more often identified sentinel nodes versus blue dye. While we did not have data on positive or negative predictive value of ICG, this will be an important area of future study.