Lymphatic mapping is essential in performing sentinel lymph node biopsy (SLNB) procedures accurately because it allows for the complete visualization of nodal groups at risk for metastases.1 While the use of Tc 99–labeled agents has been the gold standard method for lymphatic mapping in patients with melanoma, alternative visualization techniques have been explored. Most notably, indocyanine green (ICG) has been widely used for the staging of breast and gastrointestinal cancers where lymphatic drainage patterns are fairly predictable. Results using ICG dye in patients with melanoma have been mixed in retrospective studies, most likely because there is ambiguous lymphatic drainage in 25% to 40% of melanomas arising in the trunk or head and neck areas.2 In a prospective study of patients with melanomas of the trunk or extremities, Stoffels and colleagues3 found that ICG dye was inferior to Tc 99 in defining lymphatic basins containing metastases. The fluorescence signal was simply not strong enough, especially in obese patients. We agree entirely with their conclusions that Tc 99 radiocolloid remains the gold standard for lymphoscintigraphy in patients with melanoma and that single-photon emission computed tomography/computed tomography should also be used in patients with head and neck cancer.
Balch CM, Ross MI. Lymphatic Mapping and Sentinel Node Biopsy in Melanoma. JAMA Surg. 2015;150(7):623-624. doi:10.1001/jamasurg.2015.0712