Between April 16 , 2003 , and Dec 22 , 2009 , 1326 women aged 65 years or older with early breast cancer judged low-risk ( ie , hormone receptor-positive , axillary node-negative , T1-T2 up to 3 cm at the longest dimension , and clear margins ; grade 3 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 3 randomised controlled trial at 76 centres in four countries .