Ipsilateral and Concurrent Breast Cancer and Atypical Ductal Hyperplasia: Does Atypia Also Need Surgical Excision?

Background Standard-of-care management of atypical ductal hyperplasia (ADH) is surgical excision. Multiple studies have identified features of ADH in patients at low risk for upgrade who may benefit from omission of surgical excision. Patients with an ipsilateral breast cancer have been excluded from studies investigating observation for the management of ADH. Methods This was a retrospective review of women with both a breast cancer and an ipsilateral separate site of ADH diagnosed on percutaneous biopsy, who underwent excision of both sites from 2008 to 2018. Radiographic and pathologic features of ADH and cancer were analyzed, including imaging size, biopsy modality, distance between sites, cancer subtype, grade, prognostic markers, ADH foci, and presence of necrosis or micropapillary features. Final pathology at the ADH site was used to determine upgrade. Multivariable logistic regression was performed to identify variables significantly associated with ADH upgrade to malignancy. Results Among 62 women meeting the inclusion criteria, 11 (17.7%) upgraded to malignancy [9 ductal carcinoma in situ (DCIS), 2 invasive cancer] at the site of ADH. Upgrade was significantly higher with ipsilateral DCIS ( p = 0.03), ultrasound biopsy at the ADH site ( p = 0.01), and ADH with necrosis ( p = 0.04). The group at lowest risk for upgrade had stereotactic biopsy and ADH without necrosis (0% upgrade). Conclusion The presence of breast cancer does not significantly increase the likelihood for upgrade at a separate site of ipsilateral concurrent ADH above contemporary reported upgrade rates of ADH alone (10–30%). When considering breast conservation for breast cancer, omitting excision of the site of ADH can be considered when low-risk features are present.