Characteristics of multifocality/multicentricity in breast cancer and its effect on axillary lymph node metastasis

Abstract

Multifocal (MF) and multicentric (MC) breast cancers are seen with increasing frequency with advances in imaging methods. However, there is no consensus on the behavior and management of these tumors. In this study, we aimed to investigate the characteristics of MF/MC breast cancers and their relationship with axillary lymph node metastasis (ALNM). Patients who underwent surgery for breast cancer between January 2015 and January 2023 were retrospectively scanned. Exclusion criteria were as follows; male breast cancer, second primary cancer diagnosis, previous breast cancer history, previous excisional/incisional breast biopsy, neoadjuvant chemotherapy, and occult breast cancer. Multiple tumors that were closer than 5 cm to each other were defined as MF, and the others were defined as MC. T stage was determined in two different ways, using the largest tumor diameter (Tmax) and the aggregate tumor diameter (Tsum), and two different multivariate analysis models were applied. A total of 156 patients were enrolled in the study, including 130 unifocal (UF), 17 MF and 9 MC. Lymphovascular invasion (LVI) (p=0.43), ALNM (p=0.23), younger age (<50) (p=0.41) and invasive lobular carcinoma (ILC) (p<0.001) were higher in MF/MC tumors than in UFs. When comparing MF and MC, no difference was seen except progesterone receptor positivity (p=0.017). In both multivariate analyses, LVI and ILC had an effect on ALNM, while no effect of MF/MC was seen. In addition, while T stage had a significant effect on ALNM in the model using Tsum, it did not have a significant effect in the Tmax model. Our retrospective data supports that MF/MC is not a direct risk factor for ALNM and that the main factor affecting ALNM is the total tumor burden.