Reply to Alan Dal Pra, Stephane Supiot and Pirus Ghadjar's Letter to the Editor re: Giorgio Gandaglia, Stephen A. Boorjian, William P. Parker, et al. Impact of Postoperative Radiotherapy in Men with Persistently Elevated Prostate-specific Antigen After Radical Prostatectomy for Prostate Cancer: A Long-term Survival Analysis. Eur Urol 2017;72:910-7.