Background: Completion lymph node dissection (CLND) in sentinel node (SN) positive melanoma patients leads to substantial morbidity and costs, while only approximately 20% have a metastasis in non-sentinel nodes (NSNs). The aim of this study was to investigate if the biomarkers S-100B and Lactate Dehydrogenase (LDH) are associated with NSN positivity, to identify patients in whom CLND could safely be omitted.
Methods: All SN positive patients who underwent CLND at the University Medical Centre Groningen between January 2004 and January 2015 were analysed. Patient and tumor characteristics, and serum S-100B and LDH values measured the day before CLND were statistically tested for their association with NSN positivity.
Results: NSN positivity was found in 20.6% of the 107 patients undergoing CLND. Univariate analysis revealed male gender (p = 0.02), melanoma of the lower extremity (p = 0.05), Breslow thickness (p = 0.004), ulceration (p = 0.04), proportion of involved SNs (p = 0.045) and S-100B value (p = 0.01) to be associated with NSN positivity. LDH level was not significantly associated with positive NSNs (p = 0.39). In multivariable analysis, S-100B showed to have the strongest association with NSN positivity, within its reference interval of 0.20 μg/l (p = 0.02, odds ratio 5.71, 95% confidence interval 1.37-23.87).
Conclusion: In this study, the preoperatively measured S-100B value is the strongest predictor for NSN positivity in patients planned for CLND. Fluctuations of the S-100B level within the reference interval might give important clues about residual tumor load. Although further validation will be needed, this new closer look of S-100B could be of value in patient selection for CLND in the future.
Keywords: Biological tumor markers; Lymph node excision; Lymphatic metastasis; Melanoma; S100B protein; Sentinel lymph node biopsy.
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