Colorectal cancer was diagnosed in 253 participants in the screening group vs 1086 in the control group ( 112.6 vs 141.0 cases per 100,000 person-years ; absolute rate difference , 28.4 [ 95 % CI , 12.1-44 .7 ] ; HR , 0.80 [ 95 % CI , 0.70-0 .92 ] ) .