Detection of Viable CTCs Using the EPIDROP Technology in Metastatic Prostate Cancer (EPIDROP) (EPIDROP)

The use of liquid biopsy could be the key for precision medicine. Circulating tumor cells (CTCs) are the most studied circulating biomarkers used to assess the metastatic process and they have shown their clinical validity and utility in cancer patients. However, their detection and capture are still a challenge as they are very rare in the bloodstream. In this clinical trial named "EPIDROP", the investigators will use an innovative device called EPIDROP (for EPIspot in a DROP) in metastatic prostate cancer. EPIDROP is a completely new technology answering to biological and clinical questions by proposing a procedure detecting the functional subset of prostatic CTCs at the single cell level. The investigators will stain cells in the sample for EpCAM, PSMA, CD45 before to encapsulate them one by one in microdroplets and measure the PSA secretion by only the viable CTCs. This study aims to demonstrate the non-inferiority of the EPIDROP compared to the CellSearch system.

Methods : One hundred patients with a metastatic prostate cancer will be recruited plus 50 healthy donors. Twenty ml of blood will be drawn : 10 ml of blood will be drawn on CellSave tubes (fixed cells) for CTC detection using the FDA-cleared CellSearch system (gold standard) and 10 ml of blood will be drawn on EDTA tubes (viable cells) for the detection of functional CTCs using the EPIDROP. Patients will be followed for 18 months. Samples from fifty control subjects will be provided by the Etablissement Français du Sang.

Twenty ml of blood will be drawn from each patient : 10 ml of blood will be drawn on CellSave tubes (fixed cells) for CTC detection using the FDA-cleared CellSearch system (gold standard) and 10 ml of blood will be drawn on EDTA tubes (viable cells) for the detection of functional CTCs using the EPIDROP.

Inclusion Criteria : To be male, over 18 years old Metastatic prostate cancer naive to any treatment or metastatic prostate cancer in biological recurrence (PSA increase) and/or clinical recurrence after hormone suppression (mCRPC) Exclusion Criteria: Non-metastatic prostate cancer in biological and/or clinical recurrence after hormone-suppression (nmCRPC) Other active or treated cancer less than 5 years old Be protected by law (guardianship or curatorship) Be deprived of liberty by administrative decision Not being affiliated to a social security scheme, or not being a beneficiary of such a plan Being in a period of exclusion from another protocol Inability to understand and/or respond to questionnaires Inability to understand the nature, purpose and methodology of the study Refusal to sign informed consent