Abstract PO1-23-03: Management and risk of upgrade of Atypical Ductal Hyperplasia in the breast – a population-based retrospective cohort analysis

Abstract

Abstract Introduction International guidelines recommend open surgery for Atypical Ductal Hyperplasia (ADH) in the breast due to risk of underestimating malignant disease. The aim here was to evaluate the management and risk for upgrade of lesions diagnosed as ADH in percutaneous breast biopsies in two Swedish institutions. Methods All women with a screen-detected or symptomatic ADH diagnosed on percutaneous biopsy between 2013-2022 at Sundsvall and Umeå University Hospitals were included. Women with lesions classified as Breast imaging-reporting and data system (BI-RADS) 5 (highly suspicious) or 6 (confirmed malignancy) were excluded. Data were retrieved from medical records and histopathology reports. Odds ratio (OR) and 95 % confidence intervals (CI) for upgrade to malignant diagnosis after surgery was calculated by logistic regression analysis. Results Altogether, 101 women were included, mean age 56.1 years (range 36-93 years). Most women were selected from the national mammography screening program due to microcalcifications. Biopsies were performed with vacuum-assisted biopsy (VAB)(60.4%) or core-needle biopsy (CNB)(39.6%). Forty-eight women (47.5%) underwent surgery. Presence of a first degree relative with breast cancer (p < 0.001), more extensive microcalcifications (p=0.01), biopsies with ADH bordering DCIS (p=0.01) and CNB as opposed to VAB (p=0.02) increased the likelihood of surgical excision. Among the women undergoing surgery, eleven were upgraded to Ductal Carcinoma in Situ and seven to invasive breast cancer (overall upgrade rate 37.5%). In these women, no variable correlating to risk of upgrade in the surgical specimen was identified. After median 74 months of follow-up (range 4-105 months), one out of 53 women managed conservatively (1.9%) developed subsequent ipsilateral DCIS. Conclusion The upgrade rate to carcinoma was 37.5% after surgery while the estimated 5-year risk of ipsilateral upgrade in women managed conservatively was 1.9%. Acknowledging the short median follow-up time, these results indicate that the selection for non-surgical management in a subset of women was appropriate. Summary of histopathological results after surgical excision of ADH Citation Format: Charlotta Wadsten, Gunilla Rask. Management and risk of upgrade of Atypical Ductal Hyperplasia in the breast – a population-based retrospective cohort analysis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-23-03.