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.
Female patients
Age ≥ 18 years
Diagnosis of primary invasive breast cancer or ductal carcinoma in situ (DCIS)
Planned breast-conserving surgery with curative intent
Evidence of metastatic (stage IV) breast cancer
Planned mastectomy instead of breast-conserving surgery
Prior ipsilateral breast cancer surgery for the current malignancy
Inability to provide informed consent
Parallel
Standard 2D Specimen Mammography
Procedure/SurgeryTwo-dimensional specimen mammography performed intraoperatively in the radiology department to assess surgical margins following breast-conserving surgery. Images are reviewed by the operating surgeon to guide additional excision if indicated.
Mozart 3D Specimen Radiography System
DeviceIntraoperative digital breast tomosynthesis imaging performed in theatre using the Mozart 3D Specimen Radiography System (Kubtec). The system generates reconstructed 3D images of the excised specimen to allow real-time assessment of surgical margins by the operating surgeon.
Rate f positive Surgical Margins
Proportion of participants with positive margins on final histopathological assessment following breast-conserving surgery. A positive margin is defined as: Invasive carcinoma at or within 1 mm of the inked surgical margin, or Ductal carcinoma in situ (DCIS) within 2 mm of the inked margin. Margin status will be determined by blinded histopathological evaluation of the surgical specimen.
Re-Excision Rate
Proportion of participants requiring return to theatre for re-excision surgery due to positive margins identified on final histopathology.
Time From Specimen Removal to Imaging Review
Time (in minutes) from surgical excision of the specimen to completion of intraoperative imaging review by the operating surgeon.
Time From Specimen Removal to Skin Closure
Time (in minutes) from surgical excision of the specimen to final skin closure.
Total Operative Time
Total duration of surgery measured in minutes from incision to skin closure.
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