Concurrent lobular neoplasia increases the risk of ipsilateral breast cancer recurrence in patients with ductal carcinoma in situ treated with breast-conserving therapy.

BACKGROUND

Multiple clinicopathologic factors have been analyzed for their association with an increased risk of ipsilateral breast tumor recurrence (IBTR) after women receive breast-conserving treatment (BCT) for ductal carcinoma in situ (DCIS). The reported incidence of proliferative lesions, such as atypical ductal hyperplasia (ADH), columnar cell changes (CCC), and lobular neoplasia associated with breast cancer, has been as high as 23%; however, the relevance of these lesions on the natural history of DCIS and the risk of IBTR remains unknown.

METHODS

Two hundred ninety-four patients with DCIS who received BCT between 1991 and 1995 were identified from the authors' institutional database. Slides were reviewed by a dedicated breast pathologist with particular attention to the presence of lobular neoplasia, ADH, and CCC. The actuarial 5-, 10-, and 15-year IBTR rates were calculated using the Kaplan-Meier method and were compared using the log-rank test.

RESULTS

Concurrent lobular neoplasia was present in 41 of 294 patients (14%), ADH was present in 37 of 294 patients (13%), and CCC was present in 71 of 294 patients (24%). The median follow-up was 11 years. IBTR occurred in 40 of 227 patients without lobular neoplasia (18%) versus 15 of 41 patients with lobular neoplasia (37%; P=.005; hazard ratio [HR], 2.49). The 5-, 10-, and 15-year cumulative incidence rates of IBTR were twice as high in women who had DCIS and lobular neoplasia compared with women who had DCIS alone (P=.002). Concomitant ADH (HR, 1.53) and CCC (HR, 1.24) were not associated significantly with IBTR (P=.20 and P=.44, respectively).

CONCLUSIONS

Concurrent lobular neoplasia is associated with a significantly higher risk of IBTR in women with DCIS who received BCT. Women with coexisting DCIS and lobular neoplasia who receive BCT should consider using additional risk-reducing strategies.