Aim: Breast conservative surgery (BCS) and oncoplastic procedures are becoming more and more popular, providing better aesthetic outcome but one of the main draw-back of these procedures is involvement of the margin and return to theatre, causing undesired economic and cosmetic outcome in addition to psychological burden on the patients. Frozen section can decrease incidence of involved margin however, it is not always available in addition to increasing the cost. Using intra-operative ultrasound (IOUS) is a proposed solution to overcome this dilemma. Methods: In this systematic review, publication between 2001 and 2019 assessing the use of intra-operative US for margin clearance were identified in Medline Embase Cinahl Amed and the Cochrane library, with the primary outcome looking into margin involvement and return to theatre and secondary outcome as cosmetic outcome. And the volume of removed breast tissue. 7 papers were identified for this systematic review. These papers were critically appraised using PRISMA guideline, with main focus on margin involvement, and also looking into the volume of specimen removed. Conclusion: Intra-operative ultrasound can decrease return to theatre and improve surgical margin as well as cosmetic outcome and patient satisfaction. On the other hand, ultrasound overestimated the pathology margins in most cases. Margin overestimation by ultrasound may lead the surgeon to incorrectly believe that the excised margins are inappropriate. The overestimation of the majority of the tumour margins may be explained in part by the tendency of ultrasound to underestimate the pathologic tumour diameter.
