The evolution of ductal carcinoma in situ (DCIS) management has been driven by a parallel evolution in our understanding of its natural history. Early trials established the benefit of adjuvant therapies in all patients with DCIS. In contrast, subsequent studies have stratified patients to determine their eligibility for progressively less invasive and less intensive therapies. Large, randomized trials and meta-analyses have supported this shift away from treating DCIS as an homogenous disease treated with similar intensity to invasive breast cancer. This review describes the landmark studies on which current DCIS management is based.