Surgical Management of Multifocal and Multicentric Breast Cancers: Can We Achieve the Same, with Less?

The characterization and management of multifocal and multicentric breast cancer is an increasingly important topic as the incidence of diagnosis increases. The true prevalence of multiple ipsilateral breast cancer (MIBC) is unknown due to variations in definitions, detection, and pathologic sampling. The reported rate, in the era of modern imaging, ranges from 13 to 75 %. Improvements in mammographic screening, increasing use of breast ultrasound, and most significantly, the increased utilization of breast MRI for preoperative planning have increased the preoperative detection of additional lesions in many women. This trend toward increased preoperative detection of MIBC is likely contributing to rising mastectomy rates. Based on historic, retrospective studies with small number of patients that suggested an unacceptably high rate of local recurrence in women with MIBC undergoing breast-conservation therapy (BCT), many surgeons continue to recommend mastectomy for these patients. More recently, several retrospective studies have reported low local relapse rates (LR) following BCT in the MIBC population. One of the largest of these trials, by Gentilini et al., reviewed 476 patients treated with BCT for MIBC between 1997 and 2002. Despite relatively advanced disease in the study population (55 % of all patients were node-positive), the LR rate in this trial was 5.1 % at 5 years. This LR is similar to recurrence rates in the unifocal (UF) breast cancer population. The authors concluded that breast conservation is a reasonable option for women with MIBC. The results from a recent study by Ataseven et al. further buttress the argument for breast conservation in the MIBC population. This study reviewed the surgical management of women with multifocal (MF) or multicentric (MC) disease treated with neoadjuvant chemotherapy. Patients with operable or locally advanced breast cancer who were enrolled on several neoadjuvant cooperative group trials were evaluated for local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS). A total of 6134 patients were accrued of whom 13.4 % were found to have MF cancer and 9.5 % multicentric disease. The trial concluded that in patients with negative margins or a complete pathologic response, there was no statistically significant difference in LRFS when comparing UF to MIBC disease. Of note, this trial also demonstrated a significant decrease in OS in women with MC disease compared with women with UF or MF disease. The study by Kanurmuri et al. published in this volume of ASO offers a thorough review of publications that have studied the biology and behaviour of MIBC. This trial similarly concludes that MC, but not MF, disease represents a distinctly more virulent form of breast cancer that predicts a worsened OS. Women with MC breast cancer were younger with higher rates of nodal positivity and LVI. The study highlights the importance of improved definitions and characterization of MIBC to better prognosticate patient outcomes. MF and MC breast cancers appear to have distinct phenotypes—the understanding of which may lead to more tailored local therapy for these patients. This trial also identifies opportunities for improvement in local and systemic recurrence rates in women with MIBC through utilization of molecular subtyping to assess heterogeneity between separate foci of disease. Based on the data in this study, surgeons can better inform their patients about the overall risk associated with multicentric disease, including worsened recurrence-free survival and breast cancer-specific survival. This descriptive study does Society of Surgical Oncology 2015