Atypical ductal hyperplasia on core needle biopsy: Development of a predictive model stratifying carcinoma upgrade risk on excision

BACKGROUND: Although the rate of carcinoma upgrade for atypical ductal hyperplasia (ADH) diagnosed on core needle biopsy (CNB) is variable, current standard treatment consists of surgical excision (SE) for all ADH CNB diagnoses. Our objective was to identify features of ADH on CNB that may stratify carcinoma upgrade risk on SE. METHODS: We retrospectively analyzed cases diagnosed as ADH on CNB. An independent slide review and detailed analysis of radiological and clinical data was performed. Statistical analyses were used to identify predictors for upgrade. Using variables predictive of upgrade, a model to stratify the probability of upgrade of ADH diagnosed on CNB was constructed. RESULTS: We identified 124 ADH cases with subsequent SE. Of these, 62 cases (50%) were upgraded to carcinoma. Features predictive of upgrade were as follows: diagnosis of "At least ADH", percentage of cores involved by ADH, radiologic lesion size, presence of ipsilateral carcinoma, and patient age. A 4-tiered predictive model using percentage of cores involved by ADH, histologic extent of ADH, radiologic lesion size, and patient age was constructed. This predictive model has a fair accuracy, with an area under the ROC curve of 0.76. CONCLUSION: We have identified several predictors of carcinoma upgrade for ADH diagnosed on CNB. Our predictive model may be used to stratify the risk of carcinoma upgrade on SE.