Ductal carcinoma in situ (DCIS) is a biologically heterogenous entity with uncertain risk for invasive ductal carcinoma (IDC) development. Standard treatment is surgical resection often followed by radiation. New approaches are needed to reduce overtreatment. This was an observational study that enrolled patients with DCIS who chose not to pursue surgical resection from 2002-2019 at a single academic medical center. All patients underwent breast magnetic resonance imaging (MRI) exams at three to six-month intervals. Patients with hormone-receptor positive disease received endocrine therapy. Surgical resection was strongly recommended if clinical or radiographic evidence of disease progression developed. A recursive partitioning algorithm incorporating breast MRI features and endocrine responsiveness was used retrospectively to stratify risk of IDC. 71 patients were enrolled, two with bilateral DCIS (73 lesions). 34 (46.6%) were premenopausal, 68 (93.2%) were hormone-receptor positive, and 60 (82.1%) were intermediate or high-grade lesions. Mean follow-up time was 8.5 years. Over half (52.1%) remained on active surveillance without evidence of IDC with mean duration of 7.4 years. Twenty patients developed IDC, of which six were HER2-positive. DCIS and subsequent IDC had highly concordant tumor biology. Risk of IDC was characterized by MRI features after six months of endocrine therapy exposure; low, intermediate, and high-risk groups were identified with respective IDC rates of 8.7%, 20.0%, and 68.2%. Thus, active surveillance consisting of neoadjuvant endocrine therapy and serial breast MRI may be an effective tool to risk-stratify patients with DCIS and optimally select medical or surgical management.

This content is only available via PDF.

Article PDF first page preview

Article PDF first page preview

Supplementary data