Ductal carcinoma in situ is defined as breast cancer confined to the ducts of the breast without evidence of penetration of the basement membrane. Local treatment quality represents one of the most prognostic factors as half of recurrences are invasive diseases. The main goal of adjuvant radiotherapy after conservative surgery is to decrease local recurrences and to permit breast conservation with low treatment-induced sequelae. Several randomized trials have established the impact of 50 Gy to the whole breast in terms of local control. Nevertheless, no randomized trial is still available concerning the role of the boost in this disease. In this review, we present updated results of the literature and we detail the French multicentric randomized trial evaluating the impact of a 16 Gy boost after 50 Gy delivered to the whole breast in 25 fractions and 33 days. This protocol will start inclusions in October 2008.