Age<60 years, T2 stage, positive nodes, lobular histology, grading G3, diffuse lymph-vascular invasion, ductal carcinoma in situ >25%, absence of estrogenic receptors and HER-2 over-expression were considered as possible risk factors for IBRT, but none of these factors were statistically related (p=NS) with IBTR, both in all population and in exclusive IORT cohort (Table 3). Here, ERBB2 is linked to ductal breast carcinoma in situ.