S-100B: a stronger prognostic biomarker than LDH in stage IIIB-C melanoma

In melanoma patients with nodal macrometastases, the distinction between good and poor prognosis is based on the presence of primary melanoma ulceration or metastatic involvement of 4 or more lymph nodes in the 7th edition of the American Joint Committee on Cancer (AJCC) classification. We hypothesized that biomarkers would increase the accurateness of staging in these patients. The aim was to assess and compare the prognostic impact of biomarkers S-100B and LDH and to determine the best timing of their measurement in stage IIIB-C melanoma.

A total of 119 patients underwent therapeutic lymph node dissection (TLND) for nodal macrometastases with serum S-100B and LDH level measurements preoperatively. In 75 of them, S-100B and LDH were also measured on postoperative days 1 and 2. S-100B and LDH levels on days 0, 1, and 2 were compared for their association with disease-free survival (DFS) and disease-specific survival (DSS).

At a median follow-up of 17 (range 1-89) months, S-100B levels at all time points were associated with DFS. In multivariable analysis, preoperative S-100B and S-100B measured on day 2 showed the strongest association with DFS (hazard ratio [HR] 2.55, P = 0.007 and HR 3.80, P = 0.01). For DSS, the preoperative S-100B level was the strongest independent predictor (HR 2.81, P = 0.01). LDH measurements showed a significant association with DSS in univariate analysis only when measured preoperatively (HR 2.46, P = 0.01). In multivariable analysis, LDH measurement was not associated with melanoma prognosis.

The S-100B level measured preoperatively is, in contrast to LDH, one of the most important independent predictors of melanoma prognosis in patients undergoing TLND for nodal macrometastases.