Flat Epithelial Atypia: Upgrade Rates and Risk-Stratification Approach to Support Informed Decision Making

Our aim was to determine upgrade rates of pure flat epithelial atypia (FEA) to malignancy and higher-risk lesions and to identify patients with FEA at low risk for upgrade.

Medical chart review from 2007 to 2016 identified 208 consecutive patients with pure FEA diagnosed by image-guided core needle biopsy who underwent surgical excision (96.2% [200 of 208]) or had at least 2 years of imaging follow-up (3.8% [8 of 208]). Medical records were reviewed for risk factors and surgical outcomes.

Overall upgrade rate of FEA to malignancy was 2.4% (5 of 208). All 5 upgraded cases were ductal carcinoma in situ at operation. The upgrade rate to atypical ductal hyperplasia, lobular carcinoma in situ, or atypical lobular hyperplasia was 29.8% (62 of 208). The FEA lesions in patients with a genetic mutation were more likely to upgrade to malignancy than FEA lesions in patients without a genetic mutation (33.3% [1 of 3] vs 2.0% [4 of 205]; p < 0.01). The FEA lesions in patients with a personal history of breast cancer were more likely to upgrade to higher-risk lesions than those without a personal history (47.8% [11 of 23] vs 27.6% [51 of 185]; p = 0.046) but were not more likely to be upgraded to malignancy (0% [0 of 23] vs 2.7% [5 of 185]; p = 0.42).

The overall risk of upgrade of FEA to malignancy is low at 2.4%; however, the upgrade rate to a higher-risk lesion is nearly 30%. Surveillance rather than surgical excision of FEA can be a reasonable option for patients without a genetic mutation who opt against chemoprevention.