Tumor Bed Localization After Neoadjuvant Therapy

Tumor bed localization after neoadjuvant therapy is a critical step in modern breast cancer surgery. When systemic treatment has reduced or even eliminated visible tumor tissue, surgeons and radiologists still need to identify the original tumor site precisely. In this article, we explain what the tumor bed is, why its localization matters and how markers and navigation systems support accurate resection.

What Is the Tumor Bed After Neoadjuvant Therapy?

The tumor bed is the area in the breast where the primary tumor was located before neoadjuvant systemic therapy such as chemotherapy or endocrine therapy. Even when imaging shows a complete or near complete response, residual disease can still be present at a microscopic level. For this reason, the tumor bed often needs to be surgically removed, especially in breast conserving strategies.

Identifying the tumor bed correctly is essential for:

• Achieving clear surgical margins
• Reducing the need for re excision
• Planning radiation therapy fields accurately
• Ensuring reliable pathological assessment of treatment response

Why Locating the Tumor Bed Can Be Challenging

After neoadjuvant therapy, the breast may look very different compared to baseline imaging. The original mass may no longer be visible or may have changed shape. Treatment can also cause distortion, fibrosis or fat necrosis, which complicates visual interpretation.

Common challenges include:

• Loss of a clear mass or calcification pattern on imaging
• Difficulty distinguishing scar tissue from residual tumor
• Changes in breast volume or architecture

These changes highlight the importance of placing markers before or during treatment to preserve a reference point for later surgery.

Markers Used to Define the Tumor Bed

To make tumor bed localization possible, radiologists often place markers at the time of biopsy or before neoadjuvant treatment. These can be:

• Clip markers placed during core needle or vacuum assisted biopsy
• Additional clips or markers inserted before therapy in large or multifocal tumors
• Seeds or localization markers placed shortly before surgery

The combination of clip markers and preoperative localization tools helps the surgical team identify where the tumor was originally located. For more on biopsy related markers, see our article on breast biopsy devices.

Imaging Modalities for Tumor Bed Localization

Different imaging modalities can be used to evaluate and localize the tumor bed after treatment. The choice depends on how the cancer was first detected and which modality best reflects response.

• Mammography can show residual calcifications or clips placed at the tumor site.
• Ultrasound may reveal residual mass, scar tissue or the marker itself.
• MRI provides a detailed assessment of response, especially in invasive lobular carcinoma or dense breast tissue.

In some cases, MRI is indispensable to understand the extent of response and to plan precise resection. You can read more about this in our blog on MRI guided localization in breast cancer.

From Tumor Bed to Surgical Localization

Once the tumor bed has been evaluated and marked, a localization procedure is often performed before surgery. Options include wires, radioactive seeds and non radioactive magnetic seeds. The goal is to provide the surgeon with a clear target that represents the tumor bed rather than only visible residual tissue.

Magnetic seed localization, for example, allows the radiologist to place a seed at the clip site or within the tumor bed region. During surgery, the surgeon follows the signal from a handheld probe to guide resection. For a broader overview of this approach, see our article on seed localization versus wire guided localization.

How Sirius Medical Supports Tumor Bed Localization

Sirius Medical develops tools that help surgeons accurately resect the tumor bed after neoadjuvant therapy. The Pintuition Marker® can be placed at the clip location or within the tumor bed before surgery. During the operation, the Pintuition System® provides real time directional feedback to guide the surgeon to the marker and through the tissue towards the optimal resection plane.

This approach supports:

• Precise resection of the tumor bed even when no visible mass remains
• Improved margin control in breast conserving surgery
• Alignment between radiology, surgery and pathology on the true tumor site

For more context on how this fits into the overall treatment pathway, visit our clinical overview and our blog on breast cancer localization.

Interested in optimizing tumor bed localization after neoadjuvant therapy?

Request a demo or explore our resources to learn how Pintuition® can support your breast conserving surgery strategy.

Disclaimer

This article is intended for informational purposes only and should not be considered medical advice. While Sirius Medical is dedicated to improving breast cancer treatment through innovative localization technology, we do not provide medical diagnoses or treatment recommendations. If you experience any symptoms or changes in your breast health, consult a qualified healthcare professional promptly. Early medical evaluation is crucial for accurate diagnosis and effective treatment. Always seek professional guidance for concerns regarding your health.