Salvage Permanent Perineal Radioactive Seed Implantation for the Treatment of Localized Prostate Adenocarcinoma Recurrence after External Beam Radiation

Abstract

Salvage therapies for recurrences after definitive external beam radiation therapy for localized adenocarcinoma of the prostate are associated with significant morbidity and biochemical failure. We examined our experience with salvage permanent perineal radioactive seed implantation (SPPI) as a possible therapeutic option for recurrent prostate adenocarcinoma. Retrospective analysis was performed on patients who underwent SPPI for localized recurrent prostate adenocarcinoma from 1996 to 2007. Exclusion criteria were patients who underwent primary brachytherapy, radical prostatectomy, or had no follow-up. Primary outcomes were time to biochemical relapse free survival (ASTRO and Phoenix definitions: 3 consecutive PSA rises and PSA nadir +2 ng/mL) and cancer specific survival. Secondary outcomes were IPSS, IIEF5, and complications based upon Common Terminology Criteria for Adverse Events version 3. Thirty-eight patients underwent SPPI during this period. Four and 5 patients were treated with primary brachytherapy or radical prostatectomy, respectively, and an additional 4 patients had inadequate follow-up. Therefore, 13 patients were excluded, leaving a total of 25 patients for analysis. At time of salvage therapy, median PSA was 3.36 ng/mL, median PSA doubling time was 20 months, and all patients were clinically restaged at <T2 with negative transrectal ultrasound and/or MR spectroscopy. Gleason score was 6 in 7 patients, 7 in 10 patients, >8 in 3 patients (not graded in 5 patients). Initial treatment for 23 patients was EBRT, 1 patient EBRT + Proton beam, and 1 patient EBRT + LDR. The median time to the diagnosis of local recurrence was 49 months. In those who underwent SPPI median follow-up was 20 months. Cancer free survival was 96% (1 death); biochemical relapse free survival was 88% (3 patients). PSA was elevated above pre-SPPI levels at 3 months in all three failures, but lower in all 22 patients considered relapse free. Complications entailed 1 urethral stricture, 1 Grade 3 rectal hemorrhage, and 7 Grade 2 gross hematuria that resolved with conservative management. Insufficient data was available to assess IPSS or IIEF5 scores. With short-term follow-up SPPI appears to provide excellent prostate cancer control with an acceptable rate of complications for patients with local recurrence of prostate cancer after EBRT. Extended follow-up is necessary to determine long-term durability and safety of this treatment modality.