Long-term outcome for mammographically detected ductal carcinoma in situ managed with breast conservation treatment: prognostic significance of reexcision.

Background: The importance of negative final resection margins for optimal local control has been established for women with ductal carcinoma in situ (intraductal carcinoma) undergoing breast conservation treatment. This study evaluated long-term outcome after breast conservation treatment and whether reexcision or the presence of residual tumor in the reexcision specimen predicted for local recurrence in patients with ductal carcinoma in situ with negative margins.

Methods: The study cohort consisted of 192 women with ductal carcinoma in situ treated with breast conservation treatment at the University of Pennsylvania from 1978 to 2000. Analysis was performed for unilateral, mammographically detected, intraductal breast carcinomas. Study endpoints of interest included rates of local recurrence, overall survival, and cause-specific survival. The median follow-up was 6.2 years (mean, 7 years; range, 0.1-21.4 years).

Results: The 10-year overall survival and 10-year cause-specific survival rates were 87% and 99%, respectively. There were 11 local failures (6%) in the treated breast, with a 10-year actuarial local failure rate of 10% and a median time to local failure of 7.4 years (mean, 6.6 years; range, 1.6-10.2 years). Among the subset of 124 patients with negative final resection margins, there was no statistically significant difference in the 8-year actuarial local recurrence rates among patients who underwent single excision (7%), reexcision with residual tumor (8%), or reexcision with no residual tumor (0%).

Discussion: The use of breast conservation treatment in patients with ductal carcinoma in situ remains an effective and durable treatment approach. The need for reexcision to achieve negative margins and the presence of residual ductal carcinoma in situ in the reexcision specimen do not negatively impact local recurrence rates in the current study. These findings suggest that requiring more than one surgery to obtain clear resection margins is not an adverse prognostic factor for local failure.