Relation Between Primary Tumor Suvmax Value, Ki-67 Proliferation Index and Axillary Metastasis in Patients with Triple Negative Breast Cancer

Objective: The aim of our study was to determine the relationship between fluorodeoxyglucose (FDG) uptake, expressed as SUVmax of the primary tumor in F-18 FDG positron emission tomography/computed tomography (PET/CT) for staging in triple-negative breast cancer (TNBC) patients, and axillary lymph node (LN) metastasis and Ki-67 expression. Method: A total of 136 female TNBC patients who underwent F-18 FDG PET/CT imaging at our unit between July 2021 and March 2024 were retrospectively evaluated. Data on age, histopathology, hormone receptor status, Ki-67 levels, tumor location (right/left), the largest diameters of the tumor and axillary LN, axillary LN metastasis status, presence and site of distant metastasis, T stage, and clinical stage were recorded. SUVmax values of the primary breast lesions and metastatic axillary LNs were documented. Results: The mean age of the patients was 51.42±13.14 years (range: 23-86). Axillary LN metastasis was present in 95 patients (69.85%), and distant metastasis was detected in 24 patients (17.65%). No significant differences were observed between patients with and without axillary LN metastasis in terms of age, Ki-67, tumor size, tumor SUVmax, or T stage. Tumor and metastatic axillary LN sizes were positively correlated with SUVmax values. However, no correlation was found between Ki-67 and tumor size, tumor SUVmax, axillary LN size, or axillary LN SUVmax values. Conclusion: In TNBC, there is no relationship between the SUVmax value of the primary tumor in staging F-18 FDG PET/CT and axillary LN metastasis or the Ki-67 proliferation index. As expected in aggressive malignancies, primary tumor size was correlated with tumor SUVmax and metastatic axillary LN size, while metastatic axillary LN size was correlated with axillary LN SUVmax.