Prognostic relevance of lactate dehydrogenase and serum S100 levels in stage IV melanoma with known BRAF mutation status.

Abstract

Activating mutations of BRAF provide an important treatment target in patients with melanoma. The prognostic role of several biochemical markers in relation to mutation status is not clear. To analyse the prognostic significance of BRAF mutation in patients with melanoma and correlate it to different markers. In total, 162 patients with stage IV melanoma and known BRAF mutation status were included. Clinical, histopathological and laboratory information was collected and compared between patients with BRAF mutant (BRAFm) and wild-type (BRAFwt) melanoma at the time of first distant metastasis. In total, 88 patients (54%) had BRAFm melanoma (V600E/V600K). At the first distant metastasis, S100B levels in BRAFm patients were more frequently elevated (P=0·01) and significantly higher (P=0·02). Median overall survival (mOS) was significantly longer in BRAFwt patients with normal compared with patients with elevated S100B levels (P<0·01). In BRAFm melanoma, elevated S100B levels showed no prognostic influence (P=0·18). Elevated lactate dehydrogenase (LDH) levels had a significantly negative impact on mOS in both groups. mOS was increased for BRAFm patients treated with a BRAF inhibitor (BRAFi) compared with BRAFm patients not receiving BRAFi (P=0·01). No difference in mOS between BRAFm patients who did not receive BRAFi treatment and BRAFwt patients was observed. Better mOS was observed in BRAFm patients treated with BRAFi. BRAFm patients not treated with BRAFi show similar survival curves to BRAFwt patients. Elevated LDH is a BRAF-independent prognostic parameter; S100B has prognostic significance in BRAFwt melanoma only.