Multifocal/Multicentric versus Unifocal Breast Cancer: What is the Difference?

Background: Although multifocal and multicentric breast cancers are a common entity, their clinical behavior is not well characterized. With the widespread use of mammographic screening and improved sensitivity of imaging modalities, the detection of multifocal and multicentric breast cancers is likely to continuously increase. Many studies have consistently shown a correlation between multifocality and multicentricity and the rate and extent of lymph node metastases. There is little clinical data on the impact of multifocal and multicentric breast cancers on survival outcomes. This study investigates the difference between multifocal and multicentric breast cancers and unifocal breast cancer regarding pathologic and clinical parameters. We have evaluated the impact of multifocal and multicentric breast cancers on disease-free and overall survival of breast cancer patients. Methods: In this retrospective study, we reviewed the records of female patients newly diagnosed with breast cancer who presented to the department of Cancer Management and Research, Medical Research Institute, Alexandria University in the time period from January ۲۰۰۹ till December ۲۰۰۹. Patients with pathologically proven stages I-III invasive breast cancer were included in this study. Patients’ clinical and pathological characteristics were compared between the two studied groups. The disease free and overall survivals were analyzed using the Kaplan–Meier method. Results: Multifocal and multicentric breast cancers were associated with a number of known adverse prognostic factors such as higher clinical stage, larger tumor size and lymphovascular invasion. There was a significant correlation between multifocal and multicentric breast cancers and increased rate of axillary lymph node metastasis and higher N stage. Multifocal and multicentric breast cancer patients had shorter median ۵-year disease free survival and overall survival compared to unifocal breast cancer patients. In multivariate analysis, after adjustment of other factors, only clinical stage and multifocality/multicentricity were independent predictors of poor disease free and overall survival. Conclusion: There is an association between multifocal and multicentric breast cancers and known adverse prognostic factors such as increased incidence of regional lymph node metastases. This association may suggest that multifocal and multicentric breast cancers have an aggressive biology and more propensity for metastasis. Whether multifocal and multicentric breast cancer is an adverse prognostic factor in breast cancer remains controversial.