Prognosis of patients with early salvage radiotherapy and low persisting or increasing PSA levels after radical prostatectomy for prostate cancer. A retrospective comparative analysis

Title: Prognosis of patients with early salvage radiotherapy and low persisting or increasing PSA levels after radical prostatectomy for prostate cancer. A retrospective comparative analysis. Introduction: European prostate cancer guidelines include a "weak" recommendation to add hormonal therapy (ADT) to salvage radiotherapy (SRT) for better prognosis with persistent PSA values after radical prostatectomy (RP). In this study, prognosis with persistent PSA versus a PSA increase above undetectable after RP was compared. Methods: In this retrospective study of patients who underwent SRT to the prostate bed without ADT (pre-SRT-PSA ≤ 0.3 ng/ml), 243 patients had a PSA increase from undetectable (post-op PSA ≤ 0.05 ng/ml), and 110 patients had persisting PSA after RP (post-op PSA > 0.05 ng/ml). Primary endpoints: clinical progression-free survival (PFS), biochemical PFS (BPFS), metastasis-free survival (MFS), overall survival (OS). Results: BPFS rates were 66.4% with low persistent PSA versus 71.6% with recurrent PSA (p = 0.253; median follow-up, 60 [25-92] months). The low-persistent and recurrent groups also did not differ for MFS, PFS, or OS (all p > 0.05). In univariate and multivariate analyses, T3-4 and Gleason grade 4-5 predicted BPFS; T-status, R-status (R1,2), and Gleason grade influenced PFS; Gleason grade predicted MFS; and T-status predicted OS. In multivariate analysis, PSA persistence did not predict any survival outcomes (all p > 0.05). Conclusion: Prognosis with low persistent PSA values seems comparable to that with PSA levels increasing above undetectable. In the absence of other factors, ADT could be omitted in this favorable patient group. Prospective trials are needed.