Prognostic value of serial blood S100B determinations in stage IIB–III melanoma patients: A corollary study to EORTC trial 18952

Abstract

S100B is a prognostic factor for melanoma as elevated levels correlate with disease progression and poor outcome. We determined its prognostic value based on updated information using serial determinations in stage IIb/III melanoma patients.211 Patients who participated in the EORTC 18952 trial, evaluating efficacy of adjuvant intermediate doses of interferon α2b (IFN) versus observation, entered a corollary study. Over a period of 36months, 918 serum samples were collected. The Cox time-dependent model was used to assess prognostic value of the latest (most recent) S100B determination.At first measurement, 178 patients had S100B values <0.2μg/l and 33⩾0.2μg/l. Within the first group, 61 patients had, later on, an increased value of S100B (⩾0.2μg/l). An initial increased value of S100B, or during follow-up, was associated with worse distant metastasis-free survival (DMFS); hazard ratio (HR) of S100B⩾0.2 versus S100B<0.2 was 5.57 (95% confidence interval (CI) 3.81–8.16), P<0.0001, after adjustment for stage, number of lymph nodes and sex. In stage IIb patients, the HR adjusted for sex was 2.14 (95% CI 0.71, 6.42), whereas in stage III, the HR adjusted for stage, number of lymph nodes and sex was 6.76 (95% CI 4.50–10.16). Similar results were observed regarding overall survival (OS).Serial determination of S100B in stage IIb–III melanoma is a strong independent prognostic marker, even stronger compared to stage and number of positive lymph nodes. The prognostic impact of S100B⩾0.2μg/l is more pronounced in stage III disease compared with stage IIb.