Background: Circulating tumour cell (CTC)ederived organoids have the potentialto provide a powerful tool for personalised cancer therapy but are restrained by low CTCnumbers provided by blood samples. Here, we used diagnostic leukapheresis (DLA) to enrichCTCs from patients with metastatic prostate cancer (mPCa) and explored whether organoidsprovide a platform for ex vivo treatment modelling. [...]