Supplementary Material for: Patients Diagnosed with Sclerosing Adenosis in Core Needle Biopsies: When Should Excision Be Performed?

Introduction Although sclerosing adenosis (SA) carries a minimal risk of invasive breast cancer (BC), atypical lesions, ductal carcinoma in situ (DCIS), and invasive carcinoma may coexist with it. The literature does not offer a clear consensus on whether such cases warrant routine excision or can be managed through surveillance. This research aims to evaluate the efficacy of core needle biopsy (CNB) in detecting coexisting atypical or malignant lesions (A/ML) in patients diagnosed with SA, by comparing CNB results with those of secondary excisional biopsy. Additionally, it seeks to identify the preoperative factors associated with lesion coexistence, to help determine which cases require excision. Patients and Methods A retrospective analysis was conducted on 165 patients diagnosed with SA by CNB and subsequently underwent an excisional biopsy between May 2019 and September 2023 at Ankara Bilkent City Hospital, Turkey. The sensitivity and specificity of CNB in detecting A/ML coexisting with SA were evaluated. Preoperative risk factors and radiological characteristics were analyzed in a subgroup of patients with SA who showed no evidence of A/ML on CNB but subsequently underwent secondary excisional biopsy. This subgroup was dichotomized as benign or A/ML based on final pathology. Univariate and multivariate analyses were then performed to identify preoperative factors associated with lesion coexistence. Results The sensitivity and specificity of CNB in detecting A/ML coexisting with SA were 55% and 89%, respectively. In the main subgroup, age at SA diagnosis based on CNB (ROC curve cut-off: 37.5 years), lesion size (ROC curve cut-off: 1.45 cm), and preoperative magnetic resonance imaging (MRI) requirement were identified as significant predictors of coexisting A/ML in multivariate analysis. The likelihood of coexisting A/ML increased to 20.8% when two predictors were present and to 50.0% when all three were combined. Conclusion Given the limited sensitivity of CNB in detecting A/ML coexisting with SA, excisional biopsy may be warranted for selected patients—particularly those with two or more preoperative risk factors.