After a median follow-up of 67 months , the estimated disease-free survival rate at 5 years was 86.6 % in the tamoxifen-ovarian suppression group and 84.7 % in the tamoxifen group ( hazard ratio for disease recurrence , second invasive cancer , or death , 0.83 ; 95 % confidence interval [ CI ] , 0.66 to 1.04 ; P = 0.10 ) .