In the intent-to-treat ( ITT ) population one year of tamoxifen improved the disease-free-survival ( DFS ) ( hazard ratio ( HR ) = 0.87 ; 95 % confidence interval ( CI ) 0.77-0 .98 ) , the Breast Cancer Recurrence Rate ( BCRR ) ( HR = 0.79 ; 0.69-0 .90 ) and reduced the breast-cancer-specific-mortality ( BCM ) ( HR = 0.83 ; 0.73-0 .93 ) .