The rate of disease-free survival was @ % in the nodal-irradiation group and @ % in the control group ( hazard ratio for disease progression or death , @ ; @ % CI , @ to @ ; P = @ ) , the rate of distant disease-free survival was @ % versus @ % ( hazard ratio , @ ; @ % CI , @ to @ ; P = @ ) , and breast-cancer mortality was @ % versus @ % ( hazard ratio , @ ; @ % CI , @ to @ ; P = @ ) .