Four-year Experience of Interstitial Permanent Brachytherapy for Japanese Men with Localized Prostate Cancer

Abstract

To report 4 year results obtained with our initial 100 patients with localized prostate cancer treated by interstitial permanent brachytherapy. One-hundred Japanese men with clinically localized prostate cancer underwent interstitial permanent prostate brachytherapy using (125)I seeds. Median follow-up was 36 months (range, 30-42 months). Median initial prostate-specific antigen (PSA) level was 6.7 ng/ml (range, 1.5-25.2 ng/ml). Of these 100 patients, 31 received neoadjuvant hormone therapy for several months. Treatment morbidities were assessed using Radiation Therapy Oncology Group (RTOG) scale and National Cancer Institute Common Toxicity Criteria. A mean of 95 seeds (range, 48-123 seeds) were successfully implanted in patients with prostate cancer. Mean prostate volume receiving at least 100% dose (V100) and dose to 90% of prostate volume (D90) for the 100 patients were 96.6% and 166.1 Gy, respectively. Urinary morbidity was common, but was usually not severe. Only four patients needed catheterization for urinary retention (Grade 3) during follow-up. Most patients displayed no rectal morbidity after implantation, with only 3% of patients showing RTOG Grade 2 rectal morbidity and no patients showing morbidity of Grade 3 or more. Three patients experienced biochemical failure according to Phoenix consensus definition during follow-up. One patient displayed clinical failure with lymph node recurrence. These results indicate that interstitial permanent brachytherapy is safe and effective for Japanese patients with localized prostate cancer. The import of matured techniques developed in Western countries might allow bypass of the trial-and-error process in Japanese institutions.