The PSA-response to salvage radiotherapy after radical prostatectomy correlates with freedom from progression and overall survival.

BACKGROUND AND PURPOSE In a retrospective analysis, we examined factors influencing the outcome of prostate cancer (PCa) patients receiving salvage radiotherapy (SRT) for PSA recurrence after radical prostatectomy (RP). MATERIAL AND METHODS 306 patients received 3D-conformal SRT at a median pre-SRT PSA of 0.298 ng/ml. Post-SRT progression was defined as PSA ⩾0.2 ng/ml above nadir and rising further, or hormone treatment, or clinical recurrence. Data were analyzed with the Kaplan-Meier method and multivariable Cox regression. RESULTS Application of SRT at a PSA <0.2 ng/ml correlated significantly with achieving a post-SRT PSA nadir <0.1 ng/ml and with improved freedom from progression (median follow-up 7.2 years). The post-SRT nadir <0.1 ng/ml correlated significantly with less recurrences and with better overall survival. In multivariable Cox analysis restricted to pre-SRT parameters, a pre-SRT PSA ⩾0.2 ng/ml had the strongest impact (hazard ratio 2.4) on progression. If the post-SRT PSA nadir was included in the model, then failing the nadir was the most important risk factor (hazard ratio 8.1). CONCLUSIONS Early SRT at a PSA <0.2 ng/ml is a favorable treatment option for post-RP biochemical recurrence. It correlated with a post-SRT PSA-nadir <0.1 ng/ml which was associated with improved freedom from progression and overall survival.