Pure flat epithelial atypia identified on core needle biopsy does not require excision

Area of Science:

• Breast pathology
• Surgical oncology
• Radiology

Background:

• Routine excision of flat epithelial atypia (FEA) on core needle biopsy (CNB) is increasingly questioned.
• A selective excision policy for FEA has been adopted in some regions.
• This study evaluates the malignancy upstage rate following selective excision of FEA.

Purpose of the Study:

• To assess the upstage rate to malignancy after selective excision of FEA diagnosed via CNB.
• To identify clinical, radiological, and pathological factors predicting malignancy in these cases.

Main Methods:

• Retrospective review of 187 patients undergoing excision of FEA diagnosed by CNB between 2013 and 2017.
• Analysis of primary endpoint: upstage to malignancy post-excision.
• Assessment of clinical, radiological, and pathological features associated with malignancy.

Main Results:

• Nine out of 187 patients (4.8%) were upstaged to malignancy.
• Malignancy upstaging occurred in cases with concurrent atypical ductal hyperplasia (ADH) or complex sclerosing lesions (CSL).
• Pure FEA cases showed no upstaging; ADH and CSL were predictive of upstaging (p<0.001).

Conclusions:

• Pure FEA, when concordant with imaging and pathology, has a 0% upstage rate and may not require surgical excision.
• Serial imaging can be considered for pure FEA cases.
• FEA associated with other high-risk lesions, particularly ADH, warrants excision.