What is the management approach for a patient with a radial scar in the breast, particularly in terms of diagnostic workup and potential treatment options?

Management of Radial Scars in the Breast

Radial scars diagnosed on core needle biopsy should undergo surgical excision in most cases due to the risk of associated malignancy or high-risk lesions, though select patients with imaging-pathology concordance and favorable clinical features may be candidates for active surveillance with close monitoring. 1, 2

Initial Diagnostic Approach

When a radial scar is identified on imaging, the diagnostic workup should proceed as follows:

• Core needle biopsy is the preferred initial tissue sampling method rather than immediate surgical excision, allowing for histologic diagnosis while preserving tissue 1
• Marker clip placement should be performed at the time of core biopsy to identify the lesion location if it disappears or is entirely removed 1
• Ultrasound guidance can be utilized for biopsy when the lesion is visible sonographically (approximately 68% of radial scars are visible on ultrasound, most commonly appearing as hypoechoic areas or masses) 3

Decision for Surgical Excision vs. Observation

The NCCN guidelines provide clear direction on when surgical excision is mandatory versus when observation may be appropriate:

Surgical Excision is Recommended When:

• Imaging-pathology discordance exists between the core biopsy findings and radiologic appearance 1, 2
• Concurrent atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), or LCIS is present on core biopsy 1, 2
• Other concerning histologies are identified, including mucin-producing lesions, potential phyllodes tumor, or papillary lesions 1
• The pathologist expresses concern about the adequacy of sampling or histologic features 1
• The lesion increases in size on follow-up imaging during observation 1, 2

Active Surveillance May Be Considered When:

• Complete imaging-pathology concordance is present (the radial scar appearance on imaging matches the benign core biopsy findings) 2
• No atypical features or high-risk lesions are present on the core biopsy specimen 1, 2
• The patient has low overall breast cancer risk based on family history and risk assessment 2

Rationale for Surgical Excision

The traditional recommendation for surgical excision is based on the risk of upgrade to malignancy:

• Historical upgrade rates range from 1.9% to 9% when radial scars undergo surgical excision after core needle biopsy diagnosis 4, 5
• The most recent high-quality study (2024) demonstrated an extremely low upgrade rate of 1.9% in a large cohort of 106 patients who underwent surgery 4
• Radial scars can harbor adjacent carcinoma or atypical hyperplasia that may not be captured in the limited core biopsy sample 2
• Approximately 17% of excised radial scars reveal additional high-risk lesions not identified on core biopsy 6

Active Surveillance Protocol

For select patients who opt for observation rather than surgical excision, the following monitoring protocol should be implemented:

• Physical examination with or without ultrasound or mammography every 6-12 months for 1-2 years to assess stability 1, 2
• Any increase in lesion size mandates repeat tissue sampling (preferably surgical excision at that point) 1, 2
• If the lesion remains stable after 1-2 years, return to routine breast screening 1
• Recent evidence (2021) shows that among 50 patients with radial scars undergoing active surveillance with median 16-month follow-up, no lesions progressed and all either remained stable or resolved 6

Evolving Evidence and Controversy

There is emerging evidence challenging the routine excision approach:

• A 2024 study found only 1.9% upgrade rate and concluded that findings do not support excision of radial scars, even among breast cancer patients when identified at a separate site from their cancer 4
• A 2021 study of active surveillance demonstrated 99% of excised radial scars were benign with no invasive cancers, leading authors to propose that routine excision may be a low-value intervention 6
• However, NCCN guidelines (2018) continue to recommend surgical excision as the standard approach, acknowledging that select patients may be suitable for monitoring 1, 2

Special Considerations

Radial Scars Detected During Breast Cancer Workup:

• Patients with coexistent breast cancer are more likely to have radial scars detected by MRI (60% vs. 14% in screening populations) 4
• These patients tend to undergo more extensive surgery (94% vs. 75%), though the upgrade rate remains similarly low 4
• The presence of breast cancer elsewhere does not increase the upgrade risk of a separate radial scar, suggesting excision may not be necessary even in this population 4

Imaging Characteristics:

• Radial scars cannot be reliably distinguished from carcinoma by mammographic or ultrasound appearances alone 7, 3
• No ultrasound features are sufficiently specific to confidently exclude malignancy 7
• Radial scars are detected on mammogram in 60%, MRI in 25%, and ultrasound in 15% of cases 4

Common Pitfalls to Avoid

• Do not rely on imaging characteristics alone to exclude malignancy—radial scars and stellate carcinomas have overlapping appearances 7
• Do not assume that small size indicates benignity—malignancy can be associated with radial scars of any size (average size in one series was 1.42 cm) 5
• Ensure imaging-pathology concordance is explicitly documented before considering observation rather than excision 2
• Do not delay surgical excision when atypical features are present on core biopsy, as these have higher upgrade rates 1

Practical Algorithm

1. Radial scar identified on imaging → Core needle biopsy with clip placement 1
2. Review pathology for concordance with imaging and presence of atypia 1, 2
3. If imaging-pathology concordant AND no atypia → Discuss options:
   • Surgical excision (traditional standard) 1, 2
   • Active surveillance with imaging every 6-12 months for 1-2 years (emerging option for select patients) 2, 6
4. If imaging-pathology discordant OR atypia present → Surgical excision 1, 2
5. If lesion increases during surveillance → Surgical excision 1, 2