Margin Optimisation Using Z-axis Assessment With Real-time Tomosynthesis (MOZART Study).

Breast-conserving surgery is commonly performed to remove early-stage breast cancer or ductal carcinoma in situ (DCIS). During surgery, the goal is to completely remove the tumour with a clear margin of normal tissue around it. If cancer cells are found at the edge of the removed tissue (a "positive margin"), patients may need a second operation (re-excision). Re-excision can delay further treatment, increase patient anxiety, and increase healthcare costs. To help assess margins during surgery, surgeons use specimen imaging. Standard practice involves two-dimensional (2D) specimen mammography, usually performed in the radiology department. This requires temporary transfer of the specimen out of the operating theatre and provides limited depth information. The MOZART study is evaluating whether three-dimensional (3D) digital breast tomosynthesis, performed in the operating theatre using the Mozart system, improves margin assessment compared to standard 2D specimen mammography. Patients undergoing breast-conserving surgery at Beaumont Hospital who agree to participate will be randomly assigned (like flipping a coin) to one of two groups: Standard 2D specimen mammography (current standard practice), or 3D digital breast tomosynthesis performed in theatre. In both groups, the operating surgeon will review the images during surgery and decide whether additional tissue needs to be removed. The final margin status will be determined by routine laboratory analysis after surgery. The main goal of this study is to compare the rate of positive margins between the two imaging methods. Other outcomes include the need for additional surgery, operating time, and overall workflow efficiency. The results of this study may help determine whether intraoperative 3D imaging improves surgical outcomes and reduces the need for re-excision in patients undergoing breast-conserving surgery.