Patients with positive post-RT biopsy results had higher rates of biochemical failure ( hazard ratio [ HR ] = 1.7 ; 95 % confidence interval [ CI ] = 1.3-2 .1 ) and distant metastasis ( HR = 2.4 ; 95 % CI = 1.3-4 .4 ) and inferior disease-specific survival ( HR = 3.8 ; 95 % CI = 1.9-7 .5 ) .