Current Therapeutic Approaches to DCIS.

Treatment for ductal carcinoma in-situ (DCIS) has historically been extrapolated from studies of invasive breast cancer. Accepted local therapy approaches range from small local excisions, with or without radiation, to bilateral mastectomies. Systemic treatment with endocrine therapy is often recommended for hormone positive patients. With improvements in imaging, pathologic review, and treatment techniques in the modern era, combined with new information regarding tumor biology, the management of DCIS is rapidly evolving. A multidisciplinary approach to treatment is now more important than ever, with a shift towards de-escalating therapy to reduce treatment related toxicity. This review focuses on nuances of clinical management of DCIS in the modern era, highlighting key differences between DCIS as compared to invasive breast cancer. The American Cancer Society (ACS) currently recommends beginning screening with annual mammograms for women age 45, with the option to start at age 40. As treatment of DCIS has not been shown to impact survival, the USPSTF has more conservative screening recommendations of biennial mammograms from age 50-74. Unlike invasive breast cancer, DCIS is almost exclusively diagnosed by mammographic detection, and lymph node evaluation is not recommended. Pathologic review of biopsy specimens should follow the guidelines of the College of American Pathologists. Surgical management options include breast conservation, mastectomy, or possibly nipple sparing mastectomy, with upfront sentinel lymph node evaluation in the case of mastectomy. Radiation therapy is generally recommended as a component of breast conserving therapy for patients with DCIS, though in some low risk patients, there is trial data to suggest that adjuvant radiation may be omitted. Techniques for minimizing radiation toxicity should always be emphasized. Endocrine therapy is offered to women with hormone positive DCIS who have undergone lumpectomy for risk reduction, and has the benefit of decreasing incidence of events in both the ipsilateral and contralateral breast. More recent studies have explored use of targeted treatments such as trastuzumab in DCIS for HER2 overexpression. Future directions include tailoring therapy based on patient characteristics and tumor biology. With so many different options for treatment, it is also critical to engage in a discussion with the patient to arrive at a treatment decision that balances patient preferences for disease control versus treatment toxicity, financial toxicity, cosmesis, and quality of life.