Patients will be selected to present a metastatic cancer (de novo or relapse after primary tumor treatment) eligible for a first line treatment (chemotherapy, immunotherapy, endocrine therapy or targeted therapy).~All tumor subtype could be enrolled in the study; metastatic prostate cancer must be resistant to castration. Triple negative breast cancer and Hormone receptor positive, Her2-negative metastatic breast cancer resistant to endocrine therapy are eligible to the study.~A plasma sample will be collected at baseline and after the first radiologic assessment after treatment start. Plasma samples obtained at baseline will be tested for a large panel of gene and MSI status using Next Generation Sequencing (NGS) (cf table). Plasma samples obtained during treatment will be tested for the concentration of circulating DNA.~Results will be discussed within a Molecular Tumor Board (MTB) with all declared centers.
This is a prospective biomarker study that aims at demonstrating the impact of liquid biopsy to deliver better treatment for cancer patients with metastatic disease managed in the community setting