The Role of Axillary [SUV.sub.max] in [sup.18]F-FDG PET/CT in Predicting the Number of Axillary Metastases of Breast Cancer

Objective: To investigate the role of positron emission tomography/computed tomography (PET-CT) in determining the maximum number of axillary lymph node metastasis (ALNM) detectable in sentinel lymph node biopsy (SLNB). Study Design: Observational study. Place and Duration of the Study: Sivas Cumhuriyet University Faculty of Medicine, Turkiye, from January 2015 to August 2021. Methodology: A total of 104 breast cancer patients who underwent surgery after a PET-CT scan were examined. A receiver operating characteristic (ROC) analysis was utilised to determine optimal cut-off values for the standardised uptake values of the primary tumour ([pSUV.sub.max]) and axillary lymph nodes ([nSUV.sub.max]) in the presence of ALNM and the presence of more than two ALNMs. Results: The presence of more than two ALNMs was associated with [pSUV.sub.max], [nSUV.sub.max], LVI, and the number of LNs detected on PET-CT. In the ROC analysis, for the ability to predict more than two ALNMs in SLNB/axillary lymph node dissection (ALND), cut-off values were calculated as 4.65 for [pSUV.sub.max] (AUC=0.669, sensitivity=66.7%, specificity=62%, PPV=0.482, NPV=0.800, p=0.006) and 1.75 for [nSUV.sub.max] (AUC=0.838, sensitivity=81.8%, specificity=88.7%, PPV= 0.676, NPV=0.913, p