The median age at diagnosis for the Cs-131 group was 69 years, similar to the I-125 (71 years) and Pd-103 (70 years). There were significant differences among the three groups with respect to Gleason grade (p=0.007), clinical stage (p<0.0001), and pretreatment PSA (p=0.03) with the highest risk group being Pd-103. Very many patients treated with I-125 and Cs-131 had low risk by the D’Amico category. For patients who underwent Cs-131 prostate brachytherapy, 31 had Gleason Grade 6 (47.7%), 33 had Gleason Grade 7 (50.8%), and one patient had Gleason Grade 8 (1.2%) cancer. This evidence concerns the gene KLK3 and cancer.