Background The elective treatment for noninvasive breast carcinoma has not yet been established. As a result of mammographic screening programs, the incidence of noninvasive tumors has increased and has lead to the same controversy already present had with invasive carcinomas: mastectomy or conserving therapy. Methods Since 1990, 101 patients with noninvasive breast cancer were treated with irradiation following breast-conserving surgery. All the patients had irradiation of the whole breast (mean dose, 47.6 ± 1.2 Gy). The radiation dose boost to the tumor bed was delivered in 28.7% of the cases (mean dose, 21.03 ± 3.06 Gy), and in 71.3%, the boost was not administered. Results With a median follow-up of 34 months, survival is 100%. The disease-free survival at 5 years by the Kaplan-Meier method is 93.6 ± 8.65. Conclusions The conserving treatment is a valid option for treatment of patients with ductal carcinoma in situ.