Early PSA level decline is an independent predictor of biochemical and clinical control for salvage postprostatectomy radiotherapy.

Background: To improve the early detection of responders to salvage external beam radiotherapy (RT) after radical prostatectomy (RP).

Methods: Between 2002 and 2007, in a single institution, 136 consecutive patients received salvage RT to a dose of 66 Gy without androgen-deprivation therapy after RP for a rising prostate-specific antigen (PSA) level. PSA measurements were systematically performed before RT (PSART), at the fifth week of RT (PSA5), and in the follow-up at least twice a year (every 6 mo).