“…The current evidence for the oncological safety of OBCS is largely based on single-institution uncontrolled retrospective studies along with a few comparative studies where OBCS outcomes are compared to simple WLE or quadrantectomy [2,6e23]. The majority of studies showed similar pathological characteristics in terms of size, grade, subtype, hormone receptor expression and axillary node metastasis [17,18,21,24,25], although some demonstrated that larger tumour size, presence of invasive cancer and axillary nodal metastasis were more common following OBCS [8,19,20]. In these analyses OBCS was compared with WLE exclusively, but a comparison to mastectomy may have been appropriate, too, since more advanced pathology was demonstrated after OBCS.…”