Accuracy of Radiological Axillary Staging for Breast Cancer Patients with Neoadjuvant Chemotherapy

Abstract

Purpose: Neoadjuvant chemotherapy (NACT) in breast cancer patients has the advantage of decreasing related morbidities by reducing the extent of axillary surgery. However, it remains a controversy with regards to the appropriate extent of axillary lymph node dissection after NACT. Therefore, this study aims to investigate the accuracy of breast ultrasonography (US) and breast magnetic resonance imaging (MRI) to assess the axillary nodal status after NACT. Methods: We reviewed preand post-NACT axillary imaging and clinicopathological data of patients who received NACT for primary breast cancer and underwent surgery. After NACT, accuracy of imaging modalities were evaluated through the comparison of pathologic lymph node (LN) status and imaging LN status. Results: Fifty seven patients completed NACT and underwent surgery. Breast US was found to have a sensitivity of 61.1%, specificity of 57.7%, negative predictive value (NPV) of 68.2%, and positive predictive value (PPV) of 50.0%. For breast MRI, sensitivity was 58.3%, specificity 75.8%, NPV 71.4%, and PPV 63.6%. For US combined with MRI, sensitivity was 66.7%, specificity 54.5%, NPV 69.2%, and PPV 51.6%. The accuracy of imaging modalities was 59.1% for US, 68.4% for MRI, and 59.6% for US combined with MRI. Conclusion: In breast cancer patients who received NACT, MRI showed a higher specificity, NPV, and PPV than US, although it had a lower sensitivity. However, due to the low accuracy, breast MRI alone is not sufficient to determine the extent of axillary surgery. Therefore, determining the extent of axillary surgery based on the results of intraoperative sentinel lymph node biopsy may be the right method for accurate staging.