Diagnostic value of full-dose FDG PET/CT for axillary lymph node staging in breast cancer patients

Purpose The aims of this study were (1) to evaluate FDG PET/CT and CT for the detection of axillary lymph node metastases in breast cancer (BC) patients and (2) to evaluate FDG PET/CT as a pre-test for the triage to sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND). Methods The sensitivity, specificity, positive and negative predictive value (PPV, NPV), and accuracy of FDG PET/CT and CT for axillary lymph node metastases were determined in 61 patients (gold standard: histopathology). According to the equation "NPV = specificity . (1-prevalence)/[ specificity . (1-prevalence) + (1-sensitivity) . prevalence]" FDG PET/CT was evaluated as a triage tool for SLNB versus ALND. Results The sensitivity, specificity, PPV, NPV and accuracy of FDG PET/CT was 58, 92, 82, 77 and 79% and of CT 46, 89, 72, 71 and 72%, respectively. Patients with an up to similar to 60%risk for axillary lymph node metastases appear to be candidates for SLNB provided that the axilla is unremarkable on FDG PET/CT. Conclusion FDG PET/CT cannot replace invasive approaches for axillary staging but may extend the indication for SLNB.