Abstract P1-02-01: Flat epithelial atypia diagnosed on breast core biopsy: what next?

Background: Historically, atypical ductal hyperplasia (ADH) identified on breast core biopsy has been associated with a 20% upgrade to malignancy at surgical excision. Recent literature has suggested a downward trend in such upgrade rates, possibly related to the use of larger gauge core biopsy devices. It is still unclear if this applies to other high-risk lesions, such as flat epithelial atypia (FEA). As core biopsy techniques and imaging have improved, it is critical to review the correlation between FEA diagnosed on core biopsy and malignancy at final surgical excision. Methods: We performed a retrospective chart review of our institution9s medical record from 2009 to 2011 to identify all patients who (1) underwent breast core biopsy, (2) were initially diagnosed with FEA without malignancy (in situ or invasive carcinoma), and (3) proceeded with surgical excision at our institution. Results: Of the 726 breast core biopsies performed between 2009 and 2011, we identified 14 patients who met our inclusion criteria. Three patients were upgraded to malignancy following surgical excision (21%). The median age was 53.5 years, and the average breast cancer risk assessment scores were 3.5% 5-year and 18.9% lifetime. All patients underwent pre-biopsy mammogram, and four were further evaluated with ultrasound; no patients underwent a breast MRI. All of the imaging abnormalities were initially classified as BI-RADS 4, including five masses/densities and nine with suspicious calcifications. Only one patient reported the lesion as palpable on presentation and this was eventually upgraded to malignancy. All patients underwent image-guided core biopsies, including 13 stereotactic, vacuum-assisted and one ultrasound-guided, vacuum-assisted. Nine patients had 9-gauge core needle biopsies, while the remaining four patients had 11, 12, or 14-gauge needle biopsies, and this did not vary between years. Following surgical excision, three of the 14 patients (21%) were upgraded pathologically to ductal carcinoma in situ (DCIS; n=1) or invasive ductal carcinoma (n = 2). All three of these patients had 9-gauge core biopsies prior to surgical excision. Of note, four patients also had concurrent ADH on initial biopsy, although none of these were pathologically upgraded to malignancy. Of the upgrades, one patient proceeded with a definitive lumpectomy (negative sentinel lymph node biopsy) and one underwent bilateral mastectomy. The third patient is planning to undergo ipsilateral mastectomy for a subsequent diagnosis of multi-centric breast disease, including identification of an ipsilateral DCIS lesion distant from the primary lesion. Conclusions: The use of a larger gauge core biopsy needle (e.g. 9-gauge) may yield superior tissue sampling and should likely be considered as the standard of care in the evaluation of image-detected breast abnormalities. In addition, biopsy results should not be considered definitively non-malignant when a high-risk lesion is identified. While there may be a trend towards not excising some of these high-risk lesions, we believe that a core biopsy demonstrating FEA still warrants surgical excision. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-02-01.