To assess quality of surgical treatment of ductal carcinoma in situ (DCIS) and to compare teaching and non-teaching hospitals that constitute the Comprehensive Cancer Centres of the Middle Netherlands (IKMN), we retrospectively reviewed 499 patients with 502 DCIS lesions treated in the period 1989-2002. In teaching hospitals fewer patients presented with clinical symptoms compared to non-teaching hospitals (15% versus 24.0%, p = 0.01). Finally, 65% of patients underwent breast-conserving surgery and 35% of patients a mastectomy (no significant differences between the two types of hospitals). In teaching hospitals 19% of the patients had a disease-involved or unknown surgical margins versus 13% in non-teaching hospitals (p = 0.04). Twenty patients (4%) received radiation therapy postoperatively with no differences between teaching and non-teaching hospitals (p = 0.98). Quality of surgical treatment is the most important prognostic factor in treatment of DCIS. The quality of excisions should be improved and the exact status of margins should be recorded in pathology reports.