Outcomes Following Iodine-125 Monotherapy for Localized Prostate Cancer: The Results of Leeds 10-Year Single-Center Brachytherapy Experience

Purpose: This study reports the 10-year experience of permanent brachytherapy monotherapy at a single UK center. Methods and Materials: Between March 1995 and September 2004, 1,298 patients underwent trans-rectal ultrasound (TRUS) planned transperineal brachytherapy delivering 145 Gy using I-125. No patient received supplemental external beam; 44.2% received neoadjuvant hormones. In 688, CT postimplant dosimetry was available. Outcome data were analyzed in terms of overall survival (OS), disease specific survival (DSS), and PSA relapse-free survival (PSA-RFS). Results: The mean age was 62.9 (range, 34-83) years. Median follow-up was 4.9 years (range, 2.03-11.7 years). OS and DSS were 85% and 95%, respectively, at 10 years. Twenty-one patients died from prostate cancer (1.6%) and 34 (2.5%) from unrelated causes. Seventy-four (5.7%) developed evidence of clinical failure. Overall PSA-RFS was 79.9% and 72.1% at 10 years (American Society for Therapeutic Radiology and Oncology [ASTRO] and Nadir+2 definitions, respectively). Higher presenting PSA or Gleason score and use of neoadjuvant hormones were associated with an increased risk of biochemical failure (p <0.01). Biochemical control was achieved in 86.4%, 76.7%, and 60.6% (ASTRO) and 72.3%, 73.5%, and 57.6% (Nadir+2) of patients in low-, intermediate-, and high-risk groups, respectively. Biochemical control was achieved in 88% of patients with D90 ≥140 Gy and in 78% of patients with D90 <140 Gy (p <0.01). Conclusions: I-125 brachytherapy alone achieved excellent rates of medium-term biochemical control in both low- and selected intermediate-risk localized prostate cancer patients. Postimplant dosimetry improved with experience and longer follow-up, confirming the relationship of D90 with biochemical control.