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.