Accuracy and reproducibility of lymphoscintigraphy for sentinel node detection in patients with cutaneous melanoma

Lymphoscintigraphy is an important part of the mapping and identification of sentinel lymph nodes (SLNs). However, few studies report its reproducibility, and some concerns prevail. The aim of the study was to determine the reproducibility of lymphoscintigraphy performed by different team members following a strict protocol to assess lymphatic drainage and the location and number of SLNs.

Sixty-eight melanoma patients were included. All underwent 2 separate lymphoscintigraphy studies, which followed the same acquisition protocol. Discordance was defined as a change in localization or a failure to identify the SLN in one of the studies.

All patients showed lymphatic drainage, and in all cases at least 1 sentinel node was identified. In 65 of 68 patients (96%), the findings of the first lymphoscintigraphy study were similar to those of the second. This similarity was also found in the number of sentinel nodes (171 in the first study and 173 in the second). Eighty percent of patients showed 1-3 SLNs in both lymphoscintigraphy studies. The 2 studies differed in 3 patients (4%): 2 melanomas were located on the trunk and 1 on the head and neck. Drainage was visualized to more than 1 lymphatic basin in 19 patients (28%) in the first study versus 18 patients in the second study.

Lymphoscintigraphy is highly reproducible in the detection of sentinel nodes in melanoma patients. The classic protocol of radiotracer injection is reproducible and reliable enough to guarantee SLN identification, although a slight variation in isolated cases (especially when primary lesions are located on the trunk or the head and neck regions) is inevitable.