Cho WK, et al. - Researchers examined patients with positive resection margin after breast-conserving surgery (BCS) for their prognosis. Further, they assessed the role of radiation therapy (RT) in these patients. In Samsung Medical Center, 297 patients underwent BCS for breast cancer and had invasive carcinoma or ductal carcinoma in situ (DCIS) within less than 1 mm from the resection margin from January 2000 to June 2012. After 5 years, ipsilateral breast tumor recurrence (IBTR) incidence of 4.6% was observed following a median follow-up of 78 months. Multivariate analysis revealed age < 40 years, RT dose, and discontinuation of hormone therapy as the factors that were associated with IBTR. Improvement in local control in patients with invasive carcinoma or DCIS within less than 1 mm from the resection margin, could be achieved using adjuvant RT with higher dose > 66Gy EQD2.