Breast Cancer Clinical Trials: Past Half Century Moving Forward Advancing Patient Outcomes.

Clinical trials in breast cancer have contributed immensely to the advancements of modern multimodal breast cancer treatment. Due to improved screening methods and more effective biologic-based tailored systemic therapies, the extent of surgery necessary for local and systemic control of disease is decreasing. Sequential trials for ductal carcinoma in situ (DCIS) have changed the management of this disease and are culminating in randomized active surveillance studies in an effort potentially to prevent overtreatment of low- and intermediate-grade disease. For patients with initial node-positive disease, clipping and marking of the biopsy-proven nodal metastases before the start of neoadjuvant chemotherapy can allow for selective node dissection based on the axillary response. With the current advances in primary systemic therapy, feasibility trials are beginning to investigate the potential of nonoperative therapy for invasive cancers with percutaneously documented pathologic complete response. This article presents a review and update on landmark clinical trials related to DCIS, the extent of axillary surgery in node-positive disease, and the integration of systemic therapy with local therapy.