OBJECTIVES: A large meta-analysis (n>5,000) has paved the way for Circulating Tumor Cell (CTC) assessment as a biomarker in melanoma (Mocellin et al, 2006). The analysis included 53 studies with ~80% of patients having stage III-IV cutaneous melanoma. A statistically significant correlation was found for CTCs and disease stage and survival. However, standardization in more homogeneous patient populations for CTC assessment is warranted to better determine the utility in melanoma. CellSearch® (CS) CTC assay has been cleared by FDA for breast, colon and lung cancer, and a melanoma specific CTC test has been available since 2011. Here we describe CS CTC assay results in melanoma patients.

METHODS: A comprehensive literature search in PubMed was conducted investigating use of the CS CTC assay in melanoma patients. Ten prospective studies were identified that provided data on CTCs.

RESULTS: All ten studies (n ranging from 9–243, total n=769) confirmed the correlation of CTCs with stage and prognosis. The majority of pts in these studies were grade III-IV (88%). When focusing on the 7 studies that used a CTC cut-off of 1, 289 patients were Stage 3, with 37% having ≥1CTCs identified; 249 patients were Stage IV, with 44% having ≥1CTCs. In all studies for which survival data was available, CTCs were significantly associated with decreased recurrence free and/or disease free and/or overall survival, depending on the endpoints used in each study.

CONCLUSIONS: Peer-reviewed literature confirms the clinical utility of CTC enumeration in melanoma patients for prognosis and risk stratification. Because there are few prognostic blood-based biomarkers for melanoma, this pooled data highlights the need for consideration of implementing CTC information into clinical practice as a tool for risk stratification that could help guide treatment decisions. The risk stratification afforded by CTC data could also result in more efficient allocation of healthcare resources and potential cost reduction overall.