Long-term Outcome of Prostate Cancer Patients Who Exhibit Biochemical Failure Despite Salvage Radiation Therapy After Radical Prostatectomy.

OBJECTIVE - Salvage radiation therapy (SRT) is an effective treatment for recurrent prostate cancer (PCa) after radical prostatectomy. We report the long-term outcome of men who developed biochemical recurrence (BCR) after SRT and were treated >14 years ago.

METHODS - In total, 61 patients treated with SRT from 1992 to 2000 at our institution were identified. Survival was calculated by Kaplan-Meier method. Log-rank test and Cox regression were used to determine significance of clinical parameters.

RESULTS - The median follow-up was 126 months (interquartile range, 66-167 mo). Thirty-four (56%) had prostate-specific antigen (PSA) failure after SRT. At 10 years, overall survival (OS) was 67%, freedom from PSA failure (FFPF) was 33%, prostate cancer-specific survival (PCSS) was 84%, and distant metastases-free survival (DMFS) was 84%. Pathologic T-stage, Gleason score, seminal vesicle involvement, and pre-SRT PSA were associated with FFPF. For patients who failed SRT, the median time to BCR after SRT was 30 mo. A total of 19 (68%) received androgen deprivation therapy. The median OS was 13.6 years. At 10 years from time of BCR, OS was 59%, PCSS was 73%, DMFS was 75%, and castration-resistant-free survival was 70%. Early SRT failure correlated with significantly decreased DMFS and PCSS. Ten-year DMFS from SRT was 43% (BCR≤1 y) versus 91% (BCR>1 y).

CONCLUSIONS - Extended follow-up demonstrates that despite SRT failure, PCSS remains high in select patients. Early failure (≤1 y after SRT) predicted for significantly worse outcome and may represent a subgroup with more aggressive disease that may be considered for further prospective clinical studies.

Am J Clin Oncol. 2015 Jul 9. [Epub ahead of print]

Ying J1, Wang CJ, Yan J, Liauw SL, Straka C, Pistenmaa D, Xie XJ, Lotan Y, Roehrborn C, Kim DN.

1 Departments of *Radiation Oncology †Clinical Science §Urology, University of Texas at Southwestern Medical Center, Dallas ∥Department of Radiation Oncology, Texas Oncology, Waco, TX ‡Department of Radiation Oncology, University of Chicago, Chicago, IL.