Although many patients with localized prostate cancer have tumors with indolent behavior, the risk of biochemical and clinical failure rate can be high because of the presence of microscopic disease or poor local disease control in those the high-risk group, and the management of these patients is still controversial.Some studies have suggested that the high doses possible with low dose-rate brachytherapy may not require the utilization of androgen deprivation therapy or supplemental pelvic external beam radiation therapy (EBRT).Others have found that the addition of both androgen suppressive therapy and EBRT are necessary to decrease prostate cancer specific mortality The objective of this study is to evaluate the interim outcomes of tri-modality therapy consisting of long term ADT, EBRT), and low-dose rate brachytherapy (LDR-BT) for high risk prostate cancer treated at our institution.A total of 762 patients have undergone LDR-BT for localized prostate cancer at our institution from 2005 to 2014.Patients were stratified according to NCCN guidelines.Among them, 123 were in the high risk group and treated with tri-modality therapy consisting of a total median total of 29.4 months of long term ADT, and 130 Gy 125-I LDR-BT combined with a 45-Gy whole pelvic EBRT boost.95 patients with at least 2 years follow up after completion of radiation therapy who had completed their entire adjuvant ADT regimen were evaluated to calculate the biochemical and clinical outcomes.The impact of brachytherapy dose was assessed by calculating the biologically effective dose(BED) in all patients.The definition of freedom from biochemical failure (FFBF) rates were calculated using the Phoenix definition.