Analysis of Clinical and Pathologic Factors of Pure, Flat Epithelial Atypia on Core Needle Biopsy to Aid in the Decision of Excision or Observation.

backgroundThe optimal treatment of flat epithelial atypia (FEA) found on breast core needle biopsy (CNB) is controversial. We performed a retrospective review of our institutional experience with FEA to determine if excisional biopsy may be deferred.

methodsSurgical records from 2009 to 2012 were reviewed for FEA diagnosis. After exclusion for concomitant lesions, CNBs of pure FEA were classified using a previously agreed upon descriptor of "focal" versus "prominent". Data was analyzed with the Fisher's Exact and Student-t test as appropriate.

resultsOf 71 CNBs evaluated, pure FEA was identified on 27 CNBs. Final excisional biopsy was benign in 24 of 27 cases (88%) with associated ductal carcinoma in-situ (DCIS) in 3 of 27 cases (11%). Eighteen of 27 (67%) CNBs were classified as focal while 9 (33%) were described as prominent. Zero of the 18 focal patients had a malignancy compared to 3 of the 9 in the prominent group (0% vs 33%, p=0.02). Of the 27 pure FEA CNBs, 6 patients had a personal history of breast carcinoma, five DCIS and one invasive ductal carcinoma. No malignancies were found in the 21 patients without a personal history of breast carcinoma versus three in the patients with a positive history (0/21 v 3/6, p=0.007).

conclusionsOur data suggests those women who have adequate sampling and sectioning of CNBs, with focal, pure FEA on pathology, and are without a personal history of breast cancer may undergo a period of imaging surveillance. Conversely, patients with a history of breast cancer or pure, prominent FEA on CNB disease should proceed to excisional biopsy.