Monotherapeutic brachytherapy for clinically organ-confined prostate cancer

Since the mid-1980s, permanent prostate brachytherapy has been utilized increasingly as a potentially curative treatment for patients of all ages with clinically localized prostate cancer To determine the 8-year biochemical progression-free survival rate for patients who had undergone monotherapeutic brachytherapy for clinically organ-confined prostate cancer, we conducted a study of 202 patients at Schiffler Cancer Center at Wheeling Hospital in Wheeling, W.Va. These patients had undergone brachytherapy without supplemental external beam radiation therapy or androgen deprivation therapy for clinical T1b-T2c NxM0 (2002 AJCC) prostate cancer from April 1995 through May 2001. No patient underwent seminal vesicle biopsy or pathologic lymph node staging. The median follow-up was 5.2 years. All patients underwent brachytherapy more than 3 years prior to analysis. Biochemical success was defined as a PSA < 0.4 ng/mL after a nadir. Clinical, treatment and dosimetric parameters evaluated for biochemical progression-free survival included patient age, clinical T-stage, Gleason score, pretreatment PSA, risk group, percent positive biopsies, isotope, prostate volume, brachytherapy planning volume, V100/150/200, D90, tobacco status, hypertension and diabetes. For the entire group, 8-year biochemical progression-free survival was 97.4% for Pd-103 and 93.3% for I-125. The median post-treatment PSA for the entire group was < 0.1 ng/mL. In multivariate analysis, only pretreatment PSA predicted biochemical outcome with a trend for better outcome with younger patient age and lesser percent positive biopsies. The results of our study indicate that permanent interstitial brachytherapy as a monotherapeutic approach for patients with clinically organ-confined disease results in a high probability of 8-year biochemical progression-free survival with a median PSA < 0.1 ng/mL. Generous periprostatic treatment margins with documented high quality day 0 postoperative dosimetry are mandatory for such outcomes.