Objective:To investigate the long-term clinical value and safety of I125 particle implantation brachytherapy in treating high-grade non-metastatic prostate cancer.Method:We retrospectively analyzed 67 cases with Gleason score≥8 biopsy-proven non-metastatic prostate cancer from 2007 to 2017.The average age was(74.2±4.8)years old,and pre-biopsy PSA was(27.6±22.8)ng/ml.There were 35 cases(52.2%)of biopsy GS 8 and32 cases(47.8%)of biopsy GS higher than 8.There were 42 patients(62.7%)with clinical stage T2 and 2...