Comparison of radical prostatectomy and iodine 125 interstitial radiotherapy for the treatment of clinically localized prostate cancer: a 7-year biochemical (PSA) progression analysis

OBJECTIVES: To evaluate the relative efficacy of brachytherapy to radical prostatectomy, we compared biochemical progression rates from a published series of men who underwent iodine 125 (125I) interstitial radiotherapy for localized prostate cancer to a similar group of men who underwent anatomic radical prostatectomy using appropriate end points. METHODS: Seventy-six men who underwent anatomic radical prostatectomy between 1988 and 1990 were carefully matched for Gleason score and clinical stage to a recently reported contemporary series of patients treated at another institution with 125I brachytherapy without adjuvant treatment. The definition of biochemical progression was a serum PSA level greater than 0.2 ng/mL after anatomic radical prostatectomy and greater than 0.5 ng/mL for brachytherapy-treated patients. RESULTS: The 7-year actuarial PSA progression-free survival following anatomic radical prostatectomy was 97.8% (95% confidence interval CI], 85.6% to 99.7%) for this group of men selected to match the brachytherapy group, compared to 79% (95% CI not published) for men treated with 125I interstitial radiotherapy. CONCLUSIONS: Using comparative end points for biochemical-free progression, failure rates may be higher following 125I interstitial radiotherapy compared to anatomic radical prostatectomy. These data provide a better comparison of biochemical progression than previously published studies and emphasize the need for caution in interpreting the relative efficacy of brachytherapy in controlling localized prostate cancer.