The risk of developing breast cancer was similar between years 0-10 ( 226 [ 6.3 % ] in 3575 women in the placebo group vs 163 [ 4.6 % ] in 3579 women in the tamoxifen group ; hazard ratio [ HR ] 0.72 [ 95 % CI 0.59-0 .88 ] , p = 0.001 ) and after 10 years ( 124 [ 3.8 % ] in 3295 women vs 88 [ 2.6 % ] in 3343 , respectively ; HR 0.69 [ 0.53-0 .91 ] , p = 0.009 ) .