Purpose: The purpose of this retrospective study was to evaluate the diagnostic performance of positron emission tomography/computed tomography (PET/CT) with fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose (FDG) in comparison with that of ultrasonography and contrast-enhanced computed tomography (CT) in detecting axillary lymph node metastasis in patients with breast cancer.
Materials and methods: Fifty patients with invasive breast cancer were recruited. They had received no neoadjuvant chemotherapy and underwent PET/CT, ultrasonography and contrast-enhanced CT before mastectomy. The clinical stage was I in 34 patients, II in 15 patients, and III in one patient. The images of these modalities were interpreted in usual practice before surgery and the diagnostic reports were reviewed for analysis. Sensitivity, specificity, positive predictive value, and negative predictive value of each modality were obtained taking histopathological results of axillary lymph node dissection or sentinel lymph node biopsy as the reference standard.
Results: Axillary lymph node metastasis was confirmed in 15 of 50 patients by histopathological studies. PET/CT identified lymph node metastasis in three of these 15 patients. The overall sensitivity and specificity, positive predictive value, and negative predictive value of PET/CT in the diagnosis of axillary lymph node metastasis were 20, 97, 75, and 74%, and those of ultrasonography were 33, 94, 71, and 77% and those of contrast-enhanced CT were 27, 97, 80, and 76%, respectively.
Conclusions: PET/CT showed poor sensitivity and high specificity in the detection of axillary lymph node metastasis of breast cancer. Diagnostic performance of PET/CT was not superior to that of ultrasonography and contrast-enhanced CT.