Clinical significance of intra-thoracic and intra-abdominal sentinel lymph nodes detected on lymphoscintigraphy in truncal melanoma patients.

Abstract

Background: Although most melanomas drain to the more common major lymph node basins (axilla, groin, neck), rarely they drain to deep SLN locations such as intra-abdominal and intra-thoracic (including intercostal and internal mammary) sites, which pose a higher surgical risk and complexity for procurement. Our study is aimed at determining the rate of positivity and likelihood of recurrence in these nodal sites to guide management decisions for patients with truncal melanomas which drain to these 'deep' SLN locations.

Methods: Retrospective data collected between May 2008 and May 2022 including all patients with truncal melanomas who underwent lymphoscintigraphy resulting in the identification of deep SLNs in intra-abdominal and intra-thoracic sites were included. The associations between retrieval of SLNs and recurrence-free survival (RFS) and overall survival (OS) were investigated.

Results: 74 patients with a total of 91 SLNs located at deep sites were included. 11 (15 %) patients with a total of 12 lymph nodes had SLNB of these deep nodes, all of which were intercostal nodes. Only 1 patient had a positive SLNB. In total, 24 (32 %) patients developed recurrence. However, the remaining patients did not recur at the deep SLN sites. There were no statistically significant associations between retrieval of deep SLNs and RFS or OS. 3-year RFS in the patients who had deep SLNB performed was 62 % compared to 54 % and 50 % in those who had no SLNB or incomplete SLNB, respectively (p = 0.63).

Conclusion: In this study omitting procurement of these deep SLNs did not result in reduced RFS or OS.