The efficacy of preoperative imaging study for evaluation of axillary lymph node metastasis in patients with breast cancer

Abstract

Purpose: The purpose of this retrospective study was to identify the diagnostic performance of positron emission tomography/computed tomography (PET/CT) compared to conventional modalities, such as ultrasonography (US) and contrast-enhanced computed tomography (CT) in detecting axillary lymph node metastasis (ALNM) in patients with breast cancer. Methods: Two hundred thirty-three consecutive patients diagnosed with primary breast cancer who had not been treated with neoadjuvant chemotherapy and had been examined by US, CT, and PET/CT before surgery were included. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging modality and combinations of modality according to tumor size were obtained, and were compared with the histopathological results of sentinel lymph node biopsy or axillary lymph node dissection. Results: ALNM was confirmed in 32.6% (76/233) of patients. The sensitivity, specificity, PPV, NPV, and accuracy of US for detecting ALNM were 65.8%, 86.6%, 70.4%, 84.0%, and 79.8%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of CT were 72.4%, 72.6%, 56.1%, 84.4%, and 72.5%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT were 69.7%, 86.0%, 70.7%, 85.4%, and 80.7%, respectively. The combination of US and PET/CT showed the most accurate results with specificity, PPV and accuracy values of 93.6%, 81.5%, and 82.0%, respectively. Conclusion: The diagnostic performance of PET/CT was comparable to that of US and CT. Combination of US and PET/CT could be a reliable strategy for determining preoperative ALNM in patients with operable breast cancer.