Ten-year outcomes of I¹²⁵ low-dose-rate brachytherapy for clinically localized prostate cancer: a single-institution experience in Japan.

Abstract

To report 10-year outcomes of patients treated with I(125) low-dose-rate brachytherapy (BT) for clinically localized prostate cancer. A group of 1,060 patients with clinically localized prostate cancer treated with I(125) BT between March 2004 and December 2013 at the Yokohama City University Hospital were identified. The records of 743 patients with a minimum of 2 years of follow-up were reviewed. Cohorts were categorized according to National Comprehensive Cancer Network risk classification, and biochemical outcomes plus overall survival were examined. Biochemical failure was defined as nadir prostate-specific antigen (PSA) level + 2 ng/mL. Univariate and multivariate Cox proportional hazards were used to determine predictors of biochemical failure. A total of 743 patients met the criteria with a median follow-up of 54.6 months (range 24-114 months). The median age was 70 years (range 48-83). The 5- and 7-year overall survival rates were 98.8 and 97.6 %, and the 5- and 7-year biochemical failure-free survival rates were 92.6 and 91.0 %, respectively. With regard to distant metastases and survival, the 5- and 7-year metastatic-free survival rates were 98.2 and 95.9 %, respectively. A multivariate analysis revealed that initial PSA (p = 0.005; HR 1.097, 95 % CI 1.028-1.170), age (p = 0.001; HR 0.931, 95 % CI 0.893-0.971), and T stage (T1c vs. T2a) (p = 0.002; HR2.417, 95 % CI 1.319-4.267) were independent predictors of biochemical failure. I(125) low-dose-rate BT resulted in excellent survival and morbidity outcomes for localized prostate cancer at a single institution. Further studies are needed to obtain long-term outcomes.