Immunohistochemical markers affecting nodal metastasis in breast cancer and imaging methods for detection of axillary lymph node metastasis

Aim: Axillary lymph node metastasis (ALNM) is a prognostic determinant of breast cancer (BC) and influences the treatment decision. Our study aimed to determine the factors associated with ALNM in BC and to accurately evaluate the ALN status with imaging methods while determining the treatment modality. Material and Methods: Patients (n=417) who underwent BC surgery in our clinic were included. Patient's axillary ultrasound (AUS), magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) reports and immunohistochemical data were collected for analysis. Results: ALNM was found in 59.7% (n = 249) of the patients. Invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), lymphovascular invasion, and perineural invasion were found to be associated with ALNM (p<0.001). Tumor histological type was found to be the factor affecting true/false positivity or true/false negative of AUS, MRI, 18F-FDG-PET/CT (p<0.01, p=0.012, p=0.006). Discussion: Premenopause, IDC, ILC, and the presence of LVI or PNI are factors that increase the risk of ALNM. MRI is the most reliable to accurately predict ALNM, followed by AUS and 18F-FDG-PET/CT. If the tumor type is IDC and ILC, AUS and MRI may be superior in predicting ALNM positivity. All three imaging modalities may be reliable in accurately predicting axilla negativity in other tumor types.