PURPOSE: To evaluate survival and prognostic factors of 108 patients with clinically or mammographically detected ductal carcinoma in situ (DCIS), treated from 1980 to 1996 by complete local excision followed by external irradiation. PATIENTS AND METHODS: The median age was 51 (range 37-80). All the patients underwent surgery consisting of a wide resection of the mammary gland harbouring the tumour. The surgical specimens were sent to the pathologists to get information on histology and margin clearance; all the slides were reviewed by one of us to assess the tumoral diameter. External beam therapy was delivered within 8 weeks after surgery. The prescribed irradiation dose was 50 Gy in 25 fractions to be given in 5 weeks. The median duration of follow-up was 93 months (range 40-173). RESULTS: There were nine patients with local recurrence (8.3%); three patients had local recurrence of DCIS and six patients developed invasive breast cancer. The treatment of local recurrence consisted of mastectomy with or without axillary dissection (eight cases) and quadrantectomy (one case). The 5-year and 10-year ipsilateral recurrence-free rate was respectively 92 and 89%. The 10-year cause specific survival was 100%. In univariate analysis, size>or=10 mm, age<45 years old and margin status were significant P=0,02, P=0,03, P=0,005; margin status was significant in multivariate analysis (P<0,02). CONCLUSION: These results are in keeping with those of the literature. They could be improved by the mass screening campaign, which is going on since January 1990 among women aged 50-74 years.