Persistent prostate-specific antigen (PSA; >=0.1ng/ml) at 6wk after radical prostatectomy represents an independent predictor for worse long-term oncological outcome after radical prostatectomy in patients with nonmetastatic prostate cancer. Specifically, persistent PSA is associated with death and development of metastasis. In selected patients, salvage radiotherapy may lead to a survival benefit in patients with persistent PSA.