Circulating melanoma cells in peripheral blood of patients with uveal melanoma before and after different therapies and association with prognostic parameters: a pilot study

Purpose: To evaluate whether tumour therapy for malignant uveal melanoma leads to a shedding of melanoma cells into the systemic circulation. Methods: Ninety-four peripheral blood samples from 81 patients with malignant uveal melanoma were collected before and after different tumour therapies and the number of circulating melanoma cells (CMCs) was investigated (seven patients with enucleation, 49 patients with stereotactic radiotherapy, 19 patients with endoresection of the tumour, 15 patients with ruthenium-brachy-therapy and four patients with transpupillary thermotherapy). A cellular approach was used to detect CMCs through an immunocytological assay with tumour cell enrichment by immunomagnetic cell sorting. The number of CMCs was analysed further according to specific patient characteristics, tumour parameters and the development of metastasis. Results: There was no significant difference between the number of CMCs before and after the different therapies (p = 0.78). There was also no significant association between established prognostic parameters of primary uveal melanoma and the detection of CMCs (all p > 0.05). The number of CMCs was not related to the development of metastasis in a short median follow-up time of 16 months (p > 0.05). Conclusion: No changes in CMC values were observed before and after different tumour therapies. In the majority of cases therapy does not lead to a shedding of detectable melanoma cells into the systemic circulation.