After a mean 4.4 ( SD , 0.8 ) years of observation , cancer recurrence was detected in 199 participants ( 16.6 % ; 95 % CI , 14.5 % -18.7 % ) overall ; 71 of 1202 participants ( 5.9 % ; 95 % CI , 4.6 % -7.2 % ) were treated for recurrence with curative intent , with little difference according to Dukes staging ( stage A , 5.1 % [ 13/254 ] ; stage B , 6.1 % [ 34/553 ] ; stage C , 6.2 % [ 22/354 ] ) .