Arterial Blood, Rather Than Venous Blood, is a Better Source for Circulating Melanoma Cells

• CTCs were detectable in 100% of arterial blood obtained from metastatic uveal melanoma patients, while only 53% of venous blood was positive for CTCs.CTCs have been investigated to provide prognostic information in multiple tumor types. Of the multiple variables, none is more important than the appropriateness of the sample source. Blood specimens were obtained from both femoral arteries and antecubital veins in 17 uveal melanoma patients with multiple hepatic metastases. CTCs were detectable with greater frequency (100%) and in larger numbers in all arterial blood specimens than in venous samples (52.9%). Our data indicate that arterial blood specimens might be a better source of circulating uveal melanoma cells. Although less convenient, arterial blood should be evaluated as sample source for measurement of CTCs.

ABSTRACTBackgroundCTCs provide prognostic information and their application is under investigation in multiple tumor types. Of the multiple variables inherent in any such process, none is more important to outcome than the appropriateness of the sample source. To address this question, we investigated CTCs in paired peripheral venous and arterial blood specimens obtained from stage IV uveal melanoma patients.MethodsBlood specimens were obtained from both common femoral arteries and antecubital veins in 17 uveal melanoma patients with multiple hepatic metastases for CTC measurements.FindingCTCs were detectable with greater frequency (100%) and in larger numbers (median 5, range 1 to 168) in all arterial blood specimens than in venous samples (52.9%; median 1, range 0 to 8). Patients with hepatic as well as extra-hepatic metastasis showed higher number of arterial CTCs, compared to patients with liver-only metastasis (p = 0.003). There was no significant association between the number of arterial CTCs and the tumor burden within the liver in patients who had liver-only metastases.InterpretationOur data indicate that arterial blood specimens might be a better source of circulating uveal melanoma cells. Although less conveniently processed, perhaps arterial blood should be evaluated as sample source for measurement of CTCs.