Infiltrating Lobular Carcinoma of the Breast Comparison with an infiltrating ductal carcinoma

ABSTRACT

PURPOSE: Infiltrating lobular carcinomas (ILC) represent 5-10% of all breast cancers. Compared to infiltrating ductal carcinomas (IDC), ILC has a trend to be a more indistinct and multicentric form of cancer, thus, they are detected later and are less frequently treated using breast conserving surgery. The objective of this study was to determine the difference between ILC and IDC and the utility of using breast conserving surgery for ILC. METHODS: We studied 26 ILC and 319 IDC patients surgically treated at the Department of Surgery, Samsung Medical Center. Age, size of tumor, mammographic findings, operative method and pathologic findings were analysed retrospectively. For the microvessel count, tumor sections were immunohistochemically stained using CD31 monoclonal antibody, and microvessels were counted at 200 magnification in three separate fields selected from areas of highest vascularity. RESULTS: There were no differences between patients with ILC and IDC with respect to the mean age (45.4 and 47), the mean size of the tumors (2.59 cm and 2.63 cm), the malignant findings on mammography (13/15 (86.6%) and 203/237 (85.7%)(p=0.636)), and the number of breast conservaing surgeries (10/26 (38.5%) and 103/311 (33.1%)(p=0.361)). Axillary nodal metastasis was slightly more common in patients with ILC (15/25, 60%) than in those with IDC (141/284, 9.6%)(p=0.217) but there was no difference in TNM staging. More frequent estrogen receptor expression and less frequent P53 mutations were found in ILC than in IDC. Unlike IDC, there was no association between tumor microvessel density and pathologic stagings in ILC. CONCLUSION: ILC was found in patients of similar age, and the size was not different from that of IDC. The mammographic accuracy in diagnosing malignancy was about the same in ILCas in IDC. Breast conserving surgery can be performed in ILC patients at the same rate as in IDC patients. Microvessel density was not a prognostic factor in ILC patients.