Identifying Sentinel Lymph Nodes in Merkel Cell Cancer With Indocyanine Green
Posted: Monday, September 17, 2018
Published in the Journal of Surgical Research, a study conducted by Rebecca W. Knackstedt, MD, PhD, of the Cleveland Clinic Foundation, and colleagues, found that indocyanine green (ICG) fluorescence-based technology seems to improve sentinel lymph node (SLN) identification in patients with Merkel cell carcinoma. The researchers suggest they will continue enrolling more patients and investigating the technology’s role in reporting SLN in this relatively rare type of skin cancer.
“This study suggests the importance of utilizing two modalities to augment SLN identification and that ICG-based fluorescence may be able to identify nodes that would have been otherwise missed by gamma probe,” the researchers concluded.
The researchers prospectively studied patients with Merkel cell carcinoma who underwent SLN biopsy with radioisotope lymphoscintigraphy, with intraoperative handheld gamma probe, and ICG-based fluorescence imaging from 2012 to 2017. In addition, they observed a group of historical controls who underwent SLN biopsy for Merkel cell carcinoma with radioisotope lymphoscintigraphy and vital blue dye (VBD).
A total of 24 consecutive patients underwent SLN biopsy with lymphoscintigraphy and ICG-based fluorescence and 11 controls underwent SLN biopsy with lymphoscintigraphy and VBD. “The localization rate by node with VBD was 63.6% and ICG-based fluorescence was 94.8%,” Dr. Knackstedt and colleagues reported.
Positive SLNs were detected by ICG-based fluorescence alone and not by gamma probe in two patients. In addition, one patient’s singular positive node was identified through ICG fluorescence alone. “VBD or gamma probe did not identify any unique positive SLNs,” according to the researchers.