In February 2024 the EUSOMA introduced a new quality indicator for patients with ductal carcinoma in situ (DCIS) treated by breast conserving surgery (BCS). The proportion of patients without a Sentinel Lymph Node Biopsy (SLNB) was set at 90% with a minimum of 80%. Additionally, it was suggested that the upstage rate can be as low as 7-11% The purpose of this study was to evaluate the SLNB rate, the upstage rate, and metastasis rate in a large cohort of both BCS and mastectomy treated patients. Patients aged <18 years, with a DCIS biopsy were selected from the nationwide automated pathology archive (PALGA) and the Netherlands Cancer registry. Cut-off values, at which the proportion of patients without a SLNB would be less than 80%, were defined based on upstage rate and metastasis rate using previously published prediction models. Of 2269 patients, 1526 were treated with BCS. Of these, 50% did not have a SLNB, while the upstage rate was 13.2% (vacuum-assisted biopsies (VAB) 10.6%, core-needle biopsies (CNB) 20.4%). The metastasis rate was 1.0% (VAB 0.7%, CNB 2.1%). In 743 patients treated by mastectomy 2.7% did not have a SLNB, the upstage rate was 26% (VAB 19%, CNB 35%) and the metastasis rate was 4.4% (VAB 3%, CNB 6 %). At a cut-off value of 16.8% in the upstage model and of 3.9% in the metastasis model the target of more than 80% of patients without a SLNB can be achieved for patients treated by BCS or mastectomy The use of SLNB in patients with DCIS biopsy treated by BCS is well above the target set by EUSOMA. Prediction models may be helpful to further reduce the use of SLNB. The universal use of VAB will further reduce the upstage rate and metastasis rate. Although the risk of upstaging and metastasis is higher in patients undergoing mastectomy compared to those treated by BCS, the risk of metastasis is low and also in these patients the SLNB rate can be reduced.