A phase 3 clinical trial (NSABP B-35 (NCT00053898)) has found that margin widths of 1 mm vs 2 mm after lumpectomy in postmenopausal women with estrogen receptor–positive (ER+) DCIS do not result in clinically meaningful differences in rates of ipsilateral breast tumor recurrence (IBTR). The findings were presented at the American Society of Breast Surgeons conference by Dr. Irene Wapnir of Stanford Medicine. The trial included over 3,100 postmenopausal women with ER+ DCIS, all of whom received whole-breast irradiation and 5 years of hormone therapy (tamoxifen or anastrozole) after lumpectomy. Looking at 10-year rates of IBTR, the study found that rates were similar regardless of whether surgical margins…
