Imaging Case 29:
Breast cancer - Ductal Carcinoma In Situ
During breast-conserving surgery, evaluating the resected tumor specimen intraoperatively is a common practice to assess the success of the resection. This is particularly crucial for patients with Ductal Carcinoma In Situ (DCIS), who face a higher likelihood of positive margins. Conventional methods such as specimen radiography, ultrasound, and frozen section analysis, though widely utilized, have limitations in accuracy and efficiency [1].
Recent research indicates that high-resolution specimen PET-CT imaging can provide detailed visualization of the excised tumor specimen. This technique can support rapid and efficient assessment of resection completeness, potentially enhancing surgical decision-making.
Here, we illustrate how intraoperative specimen PET-CT imaging improves confidence in the operating room by offering the surgeon a clear, real-time view of the resected tissue, allowing for immediate corrective action if needed.
This case is part of the multi-center prospective BrIMA study (NCT04999917).
Patient history
A 70-year-old woman was diagnosed with Ductal Carcinoma In Situ in the right breast. The tumor size on preoperative imaging was 15 mm, biopsy showed a grade 1 tumor. Preoperative staging was cTisN0M0. Based on these findings, the patient was scheduled for breast-conserving surgery (BCS).
Figure 1: Transverse, coronal, and sagittal slices of the specimen PET-CT images of the tumor specimen, together with a 3D view. Specimen orientation is as indicated. The PET tracer scale bar is depicted on the left-hand side. These images reveal a clear region with increased 18F-FDG uptake at the inferior border of the specimen.
Specimen PET-CT imaging
Approximately one hour before surgery, the patient received an intravenous injection of 0.8 MBq/kg of 18F-FDG at the Nuclear Medicine Department. Following administration, the patient was transferred to the operating theatre, where breast-conserving surgery was performed.
First, the tumor specimen was resected with the guidance of non-radioactive radar localization. Immediately after resection, a high-resolution specimen PET-CT scan was acquired in the operating theatre. Fig. 1 presents three orthogonal views of the specimen PET-CT images, along with a 3D reconstruction.
The specimen PET-CT scan revealed increased 18F-FDG uptake at the inferior side of the specimen border. Based on these findings, the surgeon opted to perform a cavity shave in this area. According to the standard procedure, the main tumor specimen was then transported to the Radiology Department for a mammography and ultrasound to assess the margins. This standard of care margin assessment concluded complete resection of the tumor.
Histopathological evaluation
After PET-CT imaging, the surgical specimen was sent to the pathology department for routine histopathological evaluation, which was available after several days. The histopathological results are listed in Table 1.
Postoperative final pathology showed that there was a positive surgical margin at the inferior side of the main tumor specimen. Considering the cavity shave, final margin status was concluded as negative.
Table 1: Tumor characteristics assessed by histopathological evaluation.
Discussion and conclusion
In this case, histopathology results align with the specimen PET-CT images, which reveal increased 18F-FDG uptake along the inferior border. However, standard of care intraoperative margin assessment indicated a negative margin status. The surgeon's decision to perform an additional shave—guided by the specimen PET-CT findings—proved to be correct, as confirmed by histopathology, ultimately preventing a potential reoperation for the patient.
References
[1] St John et al. (2017). Diagnostic Accuracy of Intraoperative Techniques for Margin Assessment in Breast Cancer Surgery: A Meta-analysis. Ann Surg.
[2] Göker M. et al. (2020). 18F-FDG micro-PET/CT for intra-operative margin assessment during breast-conserving surgery. Acta Chirurgica Belgica. https://doi.org/10.1080/00015458.2020.1774163 ;
[3] Lambert B. et al. (2025) Feasibility study on the implementation of a mobile high-resolution PET/CT scanner for surgical specimens: exploring clinical applications and practical considerations. Eur J Nucl Med Mol Imaging. https://doi.org/10.1007/s00259-025-07143-z ;