Amanda L Amin - The University of Kansas Health System, Department of Surgery, Kansas City, USA
Onalisa D Winblad - The University of Kansas Health System, Department of Radiology, Kansas City, USA
Allison Zupon - The University of Kansas Health System, Department of Radiology, Kansas City, USA
Fan Fang - The University of Kansas Health System, Department of Pathology, Kansas City, USA

Background: NCCN guidelines recommend surgical excision for patients with atypical ductal hyperplasia (ADH) on percutaneous biopsy. Improved imaging and biopsy techniques have lower contemporary upgrade rates, challenging standard practice. We sought to identify low-risk features of ADH to define patients who may benefit from active monitoring over surgical excision. Methods: A retrospective analysis identified ۸۷ stereotactic biopsies diagnosing ADH undergoing surgical excision at a single institution from ۰۱/۲۰۰۸ to ۱۰/۲۰۱۵. Imaging was reviewed for lesion size and residual calcifications. Biopsy slides were reviewed for ADH features. Categorical variables were analyzed using Chi-square and Fisher’s exact tests; continuous variables with T- and Wilcoxon tests. Logistic regression model was used to determine the association between the number of low-risk features present and odds of upgrade. Results: Upgrade was identified in ۱۳ cases (۱۴.۹%; ۱۱ ductal carcinoma in situ and ۲ invasive breast cancer). Low-risk imaging features included imaging size <۱cm (P=۰.۰۰۴) and >۵۰% removed by biopsy (P=۰.۰۳). The only significant low-risk pathologic feature was the lack of micropapillary features (P=۰.۱۰). Focal ADH (۱-۲ foci, P=۰.۱۲) was felt to be clinically significant. Those with the lowest risk of upgrade (۰%) had all ۴ low-risk features (n=۱۷, ۲۰%). When comparing biopsies that differed by one low-risk feature, the biopsy with one less low-risk feature present had ۱۲۹% increase in odds of upgrade (exact OR=۲.۲۹, ۹۵% CI ۱.۳۵, ۴.۱۵, P=۰.۰۰۱). Conclusion: Overall upgrade rate was low in this contemporary cohort. Patients at lowest risk for upgrade had all ۴ low-risk features and could be safely offered active monitoring over surgical excision.

Breast Cancer, Atypical Ductal Hyperplasia, ADH, Breast Surgery, High Risk Upgrade