Duct carcinoma in situ of the breast: an analysis of local control after conservation surgery and radiotherapy.

Patients with duct carcinoma-in-situ are being treated with increasing frequency at our center. Between 1977 and 1988, 54 patients, including one with bilateral disease, opted for breast conserving surgery and radiation therapy. The median follow-up was 3 years (range 2-13 years). During this period, 10 patients (18%) had a recurrence in the breast; the local failure probability was 22% at 6 years (Kaplan-Meier). All patients had pre-biopsy mammograms, and in 67% this was the presenting abnormality. Thirty-three lesions (60%) required needle localization. Size, as determined by mammogram or pathology, was 2 cm or less in 60%, 2.1 to 4 cm. in 2%, and not measurable in the remainder. Close or involved margins were noted in 30% of patients who locally recurred, despite the fact that 50% had had a re-excision after their initial biopsy. Breasts which maintained local control had only 4% involved margins and re-excision was performed in only 20%. Radiation doses ranged from 4600 to 5200 cGy to the entire breast with tangential fields, followed by a boost dose in 73% of patients. No patient in the study has developed distant metastasis or died of breast carcinoma, but the local failure rate is of concern and has alerted our group to reexamine its treatment policy in patients with evidence of margin involvement. We continue to consider residual microcalcifications after surgery to be a contraindication to breast conservation.