Serum PSA evaluations during salvage radiotherapy for post-prostatectomy biochemical failures as prognosticators for treatment outcomes

Introduction: Serum prostate specific antigen (PSA) levels have proved to b e sensitive markers for the diagnosis of prostrate cancer. In addition, PSA levels are useful for detecting and monitoring prostate cancer progression after radiotherapy. Serum PSA evaluations during radiotherapy, however, ha ve not been well documented. In this study, we investigate the prognostic v alue of PSA evaluations during salvage radiotherapy for prostatectomy failu res. Methods: Forty-one patients with biochemical failures after prostatectomy t reated with salvage radiotherapy consented to have their serum PSA levels e valuated at 30 Gy and 45 Gy of irradiation. All 41 patients had negative me tastatic workup and pathologically uninvolved pelvic lymph nodes at the tim e of referral for salvage radiotherapy. Radiation therapy was delivered wit h 10-25 MV photons, with doses of 59.4-66.6 Gy. No patients received hormon al ablation therapy before irradiation. Results: The mean follow-up for all patients was 30.9 months. At last follo w-up, 28/41 patients (68.3%) were free from biochemical failure, with 20 of 41 patients (48.8%) expressing undetectable PSA levels. Serum PSA evaluati ons at 30 Gy did not significantly predict for either biochemical (p = 0.09 17) or clinical (p = 0.106) disease-free outcome. However, serum PSA evalua tions at 45 Gy significantly predicted for both biochemical (p = 0.0043) an d clinical (p = 0.0244) disease-free outcomes, with PSA elevations at 45 Gy significantly associated with poor outcomes. On univariate analysis of pro gnosticators for biochemical failures, the following were significant: an e levation in serum PSA levels at 45 Gy, detectable serum PSA immediately aft er prostatectomy, Gleason score 7-10, and serum PSA level > 1 ng/ml before salvage radiotherapy. Conclusion: Evaluation of serum PSA level at 45 Gy of salvage radiotherapy for biochemical relapses after prostatectomy may serve as a significant pro gnosticator for both biochemical and clinical disease-free outcomes. (C) 20 01 Elsevier Science Inc.