After a mean @ ( SD , @ ) years of observation , cancer recurrence was detected in @ participants ( @ % ; @ % CI , @ % -@ % ) overall ; @ of @ participants ( @ % ; @ % CI , @ % -@ % ) were treated for recurrence with curative intent , with little difference according to Dukes staging ( stage A , @ % -LSB- @/@ -RSB- ; stage B , @ % -LSB- @/@ -RSB- ; stage C , @ % -LSB- @/@ -RSB- ) .