Breast-Conserving Surgery After Neoadjuvant Chemotherapy Guided by a Supine Magnetic Resonance Imaging Projection Mapping System - Brief Communication

Sep 22, 2026

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MRI-guided breast-conserving surgery after neoadjuvant chemotherapy aims to remove the original cancer extent while ensuring a pathological response and preserving breast cosmesis. This study used an MRI projection mapping system (PMS) to visualize pre-treatment tumor extent and skin markers, enabling determination of resection boundaries without additional margins beyond the cancer region. Among 36 women, 19 avoided additional margins, associated with greater tumor diameter reduction and lower post-NAC signal ratios.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

Abstract

Study aim

Methods

Results

Conclusions

J Breast Cancer. 2026 Jun;29(3):290-298 [https://doi.org/10.4048/jbc.2025.0286](https://doi.org/10.4048/jbc.2025.0286)[ ](https://doi.org/10.4048/jbc.2025.0286)pISSN 1738-6756·eISSN 2092-9900 Brief Communication Received: Nov 8, 2025 Revised: Feb 21, 2026 Accepted: Apr 16, 2026 Published online: May 26, 2026 Correspondence to Maki Amano Departments of Radiology and Breast and Endocrine Surgery, Nihon University Hospital, 1-6 Kanda-Surugadai, Chiyoda-ku, Tokyo 101- 8309, Japan. [Email: amano.maki@nihon-u.ac.jp](Email: amano.maki@nihon-u.ac.jp) © The Authors 2026 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ([https://](https://)[ ](https://)[creativecommons.org/licenses/by-nc/4.0/](creativecommons.org/licenses/by-nc/4.0/)) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ORCID iDs Maki Amano [https://orcid.org/0000-0002-4207-5946](https://orcid.org/0000-0002-4207-5946)[ ](https://orcid.org/0000-0002-4207-5946)Jun Ozeki [https://orcid.org/0009-0002-7219-4652](https://orcid.org/0009-0002-7219-4652)[ ](https://orcid.org/0009-0002-7219-4652)Yumi Koyama [https://orcid.org/0009-0009-1983-3620](https://orcid.org/0009-0009-1983-3620)[ ](https://orcid.org/0009-0009-1983-3620)Mayumi Tani [https://orcid.org/0009-0009-3737-0842](https://orcid.org/0009-0009-3737-0842)[ ](https://orcid.org/0009-0009-3737-0842)Yuna Kaneko [https://orcid.org/0009-0009-8223-8891](https://orcid.org/0009-0009-8223-8891)[ ](https://orcid.org/0009-0009-8223-8891)Chisato Ando [https://orcid.org/0009-0002-4025-3312](https://orcid.org/0009-0002-4025-3312)[ ](https://orcid.org/0009-0002-4025-3312)Xiaoyan Tang [https://orcid.org/0000-0002-4591-5883](https://orcid.org/0000-0002-4591-5883)[ ](https://orcid.org/0000-0002-4591-5883)Fumi Nozaki [https://orcid.org/0000-0002-4384-3775](https://orcid.org/0000-0002-4384-3775) [https://ejbc.kr](https://ejbc.kr) Breast-Conserving Surgery After Neoadjuvant Chemotherapy Guided by a Supine Magnetic Resonance Imaging Projection Mapping System Visualizing Original Cancer Extent Maki Amano 1,2,3, Jun Ozeki 2, Yumi Koyama Yuna Kaneko 4, Chisato Ando 4, Xiaoyan Tang Yasuo Amano 1,6, Keiichiro Tada 7 2, Mayumi Tani 2, 5, Fumi Nozaki 5, 1Department of Radiology, Nihon University Hospital, Tokyo, Japan 2Department of Breast and Endocrine Surgery, Nihon University Hospital, Tokyo, Japan 3Department of Diagnostic Radiology, Mitsui Memorial Hospital, Tokyo, Japan 4Division of Radiological Technology, Nihon University Hospital, Tokyo, Japan 5Department of Pathology, Nihon University Hospital, Tokyo, Japan 6Department of Radiology, Nippon Medical School, Tokyo, Japan 7Department of Breast and Endocrine Surgery, Nihon University Itabashi Hospital, Tokyo, Japan ABSTRACT It is ideal to remove areas where breast cancer existed before neoadjuvant chemotherapy (NAC) in breast-conserving surgery (BCS) after NAC to ensure a pathological response. However, this becomes challenging, particularly when NAC is effective. It is also important to determine the appropriate resection line to maintain breast cosmesis in the absence of residual cancer cells. We aimed to identify magnetic resonance imaging (MRI) findings that enable the removal of the original cancer extent without additional margins outside the cancer boundary in BCS after NAC using an MRI projection mapping system (PMS) . We enrolled 36 women with breast cancer in the study. Contrast-enhanced MRI was performed in the prone and supine positions before NAC. Supine unenhanced MRI with skin markers for registration was performed after NAC, one day before surgery. A maximum intensity projection image visualizing both the tumor extent before NAC and skin markers was projected onto the breast using PMS, and BCS was performed. We compared the clinical, pathological, and MRI findings be

FAQs

What clinical problem does MRI-PMS address in breast-conserving surgery after NAC?

It helps surgeons identify the original cancer extent and appropriate resection lines when NAC is effective, aiming to avoid additional margins while maintaining cosmetic outcomes.

How was the MRI projection mapping system used in the study?

Contrast-enhanced MRI was performed before NAC, then supine unenhanced MRI with skin markers was done after NAC. A maximum intensity projection image was projected onto the breast using PMS for surgery.

Which patients were less likely to require additional margins?

Patients who did not need additional margins showed a higher tumor diameter reduction rate and a lower signal ratio between the tumor bed and normal tissue after NAC.

Sep 22, 2026

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