Reply to Vincenza Conteduca, Giorgia Gurioli, and Ugo De Giorgi's Letter to the Editor re: Niven Mehra, David Dolling, Semini Sumanasuriya, et al. Plasma Cell-free DNA Concentration and Outcomes from Taxane Therapy in Metastatic Castration-resistant Prostate Cancer from Two Phase III Trials (FIRSTANA and PROSELICA). Eur Urol. In press. https://doi.org/10.1016/j.eururo.2018.02.013