Between April @ , @ , and Dec @ , @ , @ women aged @ years or older with early breast cancer judged low-risk ( ie , hormone receptor-positive , axillary node-negative , T@-T@ up to @ cm at the longest dimension , and clear margins ; grade @ tumour histology or lymphovascular invasion , but not both , were permitted ) , who had had breast-conserving surgery and were receiving adjuvant endocrine treatment , were recruited into a phase @ randomised controlled trial at @ centres in four countries .