Selecting patients for breast-conserving therapy: the importance of lobular histology.

Overview

BACKGROUND: Concerns exist regarding the ability to select patients with lobular carcinoma for breast-conserving therapy (BCT) using mammography. The purpose of this study was to compare the conversion rate from BCT to mastectomy among patients with lobular (ILC) and ductal carcinoma (IDC), and to compare the number of resections needed to obtain negative margins. METHODS: In all, 349 patients with pure or mixed ILC were identified from a database and 318 were successfully matched to 2 controls with IDC on the basis of year of diagnosis, menopausal status, and stage of disease. Conditional logistic regression was used to control for matching. RESULTS: Patients with ILC were older, had larger tumors (2.6 vs. 2.1 cm; P<.001), and were more likely to have contraindications to BCT (25% vs. 20%). In patients thought to be candidates for BCT, no difference in success rate was noted on the basis of histologic type after controlling for age and stage. In those undergoing BCT, no difference in the number of procedures was seen on the bases of histology after adjustment for age and stage. CONCLUSIONS: Patients with ILC are not more likely to fail BCT than those with IDC, nor do they require more operations to obtain negative margins. These results do not support the use of more extensive preoperative evaluation such as magnetic resonance imaging in patients with ILC.