Circulating tumor cells and survival in abiraterone- and enzalutamide-treated patients with castration-resistant prostate cancer.

Background: The outcome to treatment administered to patients with metastatic castration-resistant prostate cancer (mCRPC) greatly differs between individuals, underlining the need for biomarkers guiding treatment decision making.

Objective: To investigate the prognostic value of circulating tumor cell (CTC) enumeration and dynamics, in the context of second-line endocrine therapies (ie, abiraterone acetate or enzalutamide), irrespective of prior systemic therapies.

Design, Settings, And Participants: In a prospective, multicentre study blood samples for CTC enumeration were collected from patients with mCRPC at baseline (n = 174).