RESUMO
BACKGROUND/AIM: Positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose (18F-FDG) has recently been used to investigate lymph node (LN) metastases and several predictive features in patients with breast cancer (BC). The aim of this study was to assess the value of this non-invasive imaging procedure for axillary staging. PATIENTS AND METHODS: Fifty patients with early primary unilateral, locally advanced, or recurrent invasive operable BC were enrolled. All patients underwent preoperative 18F-FDG PET/CT, and the results were compared with the histopathology of dissected axillary LNs and their biological and immunohistochemical characteristics. The diagnostic performance of 18F-FDG PET/CT in detecting LN metastases from primary or recurrent BC was analyzed. The mean values of the initial PET/CT parameters, including the primary tumour (SUV T) and ipsilateral axillary LNs (SUV LN), were compared with the clinicopathological features of patients to determine their usefulness for predicting clinical interactions. RESULTS: The sensitivity, specificity, overall accuracy, positive predictive value, and negative predictive value of 18F-FDG PET/CT for axillary LN staging were 87%, 90%, 88%, 93%, and 82%, respectively. Bivariate analyses showed strong interactions of nuclear grade (p=0.05), progesterone receptor expression (p=0.001), Ki-67 index (0.027), and local relapse with the SUV T. A high SUV LN value was significantly correlated with a higher nuclear grade score (p=0.05), oestrogen receptor negativity (p=0.001), progesterone receptor negativity (p=0.014), a high Ki-67 index (>20%; p=0.048), LN metastasis (p<0.001), a basal tumour (p=0.04), and locoregional recurrence (p<0.001). CONCLUSION: PET/CT is a reproducible, non-invasive imaging modality that is useful for evaluating a primary BC mass and its relationship with metastatic axillary LNs, thereby predicting tumour behaviour and guiding clinical practice.