Abstract IA019: Surgery for DCIS: If, what and when

DCIS is traditionally viewed as a surgical problem managed in a comparable way to invasive breast cancer, by breast conservation or mastectomy, to prevent the evolution of intraductal to invasive disease. The need for surgery has been challenged by retrospective case series demonstrating that progression from DCIS to invasive disease is variable, increases with time, but may be modified by endocrine therapy. This data has led to the innovative trials currently under way of active monitoring compared with surgery – the “if” of whether surgery is needed. What surgery to perform requires pathology confirmation of the diagnosis, awareness of the heterogeneity of DCIS (and the potential for sampling to miss invasive disease) together with imaging by mammography, ultrasound and/or MRI. Clinical impressions, imaging and pathology findings direct treatment options. Surgery comprises lumpectomy versus simple, skin sparing or nipple sparing mastectomy (with consideration for reconstruction) potentially partnered with axillary node surgery, at least for those undergoing mastectomy. When (and how) to perform surgical and allied techniques is undergoing change. The required surgical margins of 2mm (for pure DCIS) at the time of conservation to reduce local recurrence remains challenging, with technologies such as optical coherence tomography demonstrating promise for intraoperative determination of adequate margins. Rather than routine sentinel lymph node biopsy, with the attendant risks of lymphedema, iron oxide/dextran coated particles injected prior to surgery, rapidly migrate to and lodge in the axillary nodes and provide an option for delayed axillary surgery if invasive disease is identified. Neoadjuvant approaches to DCIS, targeting the estrogen receptor or HER2, to downstage the extent of surgery are less favored than for invasive breast cancers, but DCIS may be the residue left after neoadjuvant treatment for invasive disease. However, adjuvant endocrine therapy and adjuvant radiotherapy may each have an impact on reducing the chance of re-occurrence of DCIS or development of invasive cancer. Currently, surgery remains the primary treatment for DCIS. If surgery is performed, what is done and when surgery takes place varies with the nature, the extent of the DCIS and is influenced by patient preference.

Citation Format: Alastair M. Thompson, Elizabeth Bonefas, Stacey Carter, Ivan marin, Huma Javaid, Jessica Montalvan. Surgery for DCIS: If, what and when [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr IA019.