Multifocal and Multicentric Breast Carcinoma: A Significantly More Aggressive Tumor than Unifocal Breast Cancer.

BACKGROUND/AIM: There are still many questions that surround multifocal or multicentric breast carcinoma (MMBC). The aim of this study was to analyze the clinicopathological characteristics of MMBC and provide feasible suggestions for therapy. PATIENTS AND METHODS: A total of 156 cases of MMBC in 3,597 invasive ductal breast carcinomas were collected and reviewed. Some factors related with prognosis such as tumor size, lymph node metastasis and others were assessed in each tumor focus, and mismatches among foci were recorded. RESULTS: The majority of MMBC had aggregate dimensions over 2 cm (85.90%). The rate of axillary lymph node metastasis was 56.41% (88/156) compared to unifocal tumors of 33.01% (1,136/3,441). Most cases had higher Ki-67 proliferative indices (91/156). Mismatches in ER status were present in 6 cases, PR in 4 cases, proliferative index (Ki-67) in 9 cases and HER2-positive status in 2 cases. CONCLUSION: The larger aggregate dimension of tumor, the higher metastatic rate of axillary lymph node and the high Ki-67 proliferative index seen in most cases, suggest that MMBC is biologically more aggressive than unifocal breast cancer. In addition, every focus should be tested owing to the existence of different expressions of immunostaining between foci.