A comparative study of 18F-FDG PET/CT and ultrasonography in the diagnosis of breast cancer and axillary lymph node metastasis.

Background: The aim of this study was to compare the diagnostic value of 18F-FDG-PET/CT (PET/CT) with ultrasonography (US) in detection of primary breast cancer and axillary lymph nodes (ALN) metastasis of breast cancer.
Methods: One hundred and sixty four patients with breast carcinoma were recruited and analyzed retrospectively. All patients underwent PET-CT and US. The PET/CT scan results for the diagnosis of primary breast cancer were compared with US. The diagnostic accuracy of PET/CT in detecting ALN metastasis was compared with histopathology.
Results: In 164 patients with cytologically established breast carcinoma, the sensitivity of PET/CT and US in the diagnosis of breast cancer were 86% (141/164), 91% (149/164), respectively. The sensitivity, specificity of PET/CT and US in ALN staging were 46% and 54%, 91% and 91%, respectively. The diagnostic accuracy of PET/CT correlated with the ALN size, the SUVmax of primary breast cancer (P=0.02 and 0.04).
Conclusions: PET/CT is very expensive, and not superior to US in detection of primary breast cancer and in ALN staging, but superior in detecting distant metastases. PET/CT cannot be recommended as a primary diagnostic procedure in early breast cancer. US should still remain the first line for the diagnosis of stage I breast cancer. In relation to the detection of axillary node metastases, both PET/CT and ultrasonography have poor sensitivity, and cannot replace staging by using the sentinel node procedure.