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

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.

Study Overview

• Status: Recruiting
• Conditions: Breast Cancer
• Intervention / Treatment: Procedure: Standard 2D Specimen Mammography; Device: Mozart 3D Specimen Radiography System

Detailed Description

Below are ClinicalTrials.gov-ready versions of both sections. They follow plain-language guidance, avoid promotional tone, and avoid duplicating structured registry fields.

Brief Summary

(Plain-language, patient-facing; within 5,000 characters)

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.

Detailed Description

(Technical, structured, avoids repeating registry fields; within 32,000 characters)

Background and Rationale

Breast-conserving surgery (BCS) is a standard surgical treatment for early-stage invasive breast cancer and ductal carcinoma in situ (DCIS). Achieving clear surgical margins is essential to minimise local recurrence risk and reduce the need for re-excision. Despite current intraoperative assessment techniques, reported positive margin rates range from 15-20%, and a substantial proportion of patients require additional surgery.

Intraoperative specimen imaging is used to guide margin assessment. Standard practice involves 2D specimen mammography performed in the radiology department. Limitations of this approach include:

Specimen transport outside the operating theatre Potential workflow delays Limited three-dimensional assessment of tumour-margin relationships Difficulty interpreting complex lesions or microcalcifications Digital breast tomosynthesis (DBT) provides three-dimensional imaging through multiple reconstructed slices. The Mozart 3D Specimen Radiography System enables intraoperative DBT imaging directly within the operating theatre. This may improve visualisation of margins and allow more accurate real-time surgical decision-making.

Prospective observational data suggest improved diagnostic accuracy with intraoperative DBT compared to standard specimen mammography. However, high-quality randomised controlled trial data are limited.

Study Design

The MOZART study is a prospective, single-centre, open-label, parallel-group randomised controlled trial conducted at Beaumont Hospital.

Eligible patients undergoing breast-conserving surgery will be randomised in a 1:1 ratio to:

Standard intraoperative 2D specimen mammography (control group), or

Intraoperative 3D digital breast tomosynthesis using the Mozart system (intervention group).

Randomisation will be computer-generated. Surgeons and participants will not be blinded due to the nature of the intervention. Histopathologists assessing final margin status and data analysts will be blinded to group allocation.

Intervention Procedures Control Group

Specimen imaging will be performed in the radiology department using standard 2D mammography. The operating surgeon will review images and determine whether additional excision is required.

Intervention Group

Specimen imaging will be performed in theatre using the Mozart 3D digital breast tomosynthesis system. The surgeon will assess reconstructed tomosynthesis images in real time and determine whether additional excision is required.

In both groups, standard surgical technique and postoperative management will not be altered.

Outcomes

The primary outcome is the rate of positive surgical margins on final histopathological assessment.

Positive margins are defined according to contemporary national and international guidance as:

Invasive carcinoma at or within 1 mm of the inked margin; or DCIS within 2 mm of the margin.

Secondary outcomes include:

Re-excision rate Operative time metrics Time from specimen removal to imaging review Theatre workflow efficiency Cost-effectiveness analysis

• Study Type: Interventional
• Enrollment (Estimated): 314
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Prof Arnold Hill, MB, BCh, BAO, MCh, FRCSI; Phone Number: 018093000; Email: adkhill@rcsi.com
• Study Contact Backup: Name: Aisling Hegarty, PhD; Email: Aislinghegarty@rcsi.ie

Study Locations

• Ireland
  • Dublin
    • Beaumont, Dublin, Ireland, D09V2N0
      • Recruiting
      • Beaumont RCSI Cancer Centre
      • Contact: Aisling Hegarty, PhD; Phone Number: 0035317977800; Email: Aislinghegarty@rcsi.ie

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Female patients
• Age ≥ 18 years
• Diagnosis of primary invasive breast cancer or ductal carcinoma in situ (DCIS)
• Planned breast-conserving surgery with curative intent
• No clinical or radiological evidence of distant metastatic disease at time of recruitment
• Able to provide written informed consent
• Fluent in English (spoken and written)

Exclusion Criteria:

• 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
• Participation in another interventional study that may affect surgical margin assessment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Standard 2D Speciman Mammography (Control); Participants undergo intraoperative specimen imaging using standard two-dimensional (2D) specimen mammography performed in the radiology department following tumour excision. The operating surgeon reviews the images intraoperatively to assess margin adequacy and determines whether additional excision is required prior to wound closure. All other aspects of surgical care follow standard institutional practice.	Procedure: Standard 2D Specimen Mammography; Two-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.
Experimental: 3D Digital Breast Tomosynthesis (Mozart System Intervention); Participants undergo intraoperative specimen imaging using three-dimensional (3D) digital breast tomosynthesis with the Mozart 3D Specimen Radiography System, performed directly in the operating theatre. The operating surgeon reviews reconstructed tomosynthesis images in real time to assess margin adequacy and determine whether additional excision is required prior to wound closure. All other aspects of surgical care remain unchanged.	Device: Mozart 3D Specimen Radiography System; Intraoperative 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	Within 4 weeks after index surgery (upon availability of final histopathology report)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Re-Excision Rate	Proportion of participants requiring return to theatre for re-excision surgery due to positive margins identified on final histopathology.	Within 3 months after index surgery
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.	Intraoperative (day of surgery)
Time From Specimen Removal to Skin Closure	Time (in minutes) from surgical excision of the specimen to final skin closure.	Intraoperative (day of surgery)
Total Operative Time	Total duration of surgery measured in minutes from incision to skin closure.	Intraoperative (day of surgery)
Cost-Effectiveness Analysis	Comparative evaluation of theatre time costs, radiology utilisation, and re-operation rates between intervention and control groups. Incremental cost-effectiveness ratio will be calculated based on cost per margin-negative surgery achieved.	At study completion (after all participants have completed follow-up)

Collaborators and Investigators

• Sponsor: Royal College of Surgeons, Ireland

Study record dates

Study Major Dates

• Study Start (Actual): December 18, 2025
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: February 16, 2026
• First Submitted That Met QC Criteria: February 16, 2026
• First Posted (Actual): February 23, 2026

Study Record Updates

• Last Update Posted (Actual): April 3, 2026
• Last Update Submitted That Met QC Criteria: March 30, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Breast Cancer; MOZART
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: 25-61

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No