The Value of F-18-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for the Detection of Residual Breast Tumor or Axillary Metastasis after Neoadjuvant Chemotherapy in Invasive Ductal Carcinoma of the Breast

Abstract

Introduction: Accurate evaluation of pathological response after neoadjuvant chemotherapy would aid in treatment and surgical planning as well as prediction of outcomes. This study examined the value of F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/ CT) in predicting pathologically confirmed residual tumor in breast or presence of axillary metastasis when performed after completion of neoadjuvant therapy in patients with invasive ductal carcinoma (IDC) of the breast cancer. Methods: This retrospective study included 52 IDC of the breast who received neoadjuvant chemotherapy and underwent F-18-FDG PET/CT between 2015 and 2019 after completion of neoadjuvant chemotherapy. Diagnostic performance parameters of F-18-FDG PET/CT for predicting residual tumor or presence of axillary metastasis were estimated based on histopathological findings. Results: All patients had IDC. F-18-FDG PET/CT exhibited high specificity for both locations (89.5% and 93.8% and for breast and axilla, respectively). The sensitivity of the method, on the other hand, was low for both locations (66.7% and 30.0% for breast and axilla, respectively), particularly for axilla. Falsenegative rate (i.e., missing rate) for breast and axilla was 9.1% and 0% for the tumors >8 mm in diameter. Conclusion: F-18-FDG PET/CT does not seem to provide reliable information on the presence of a residual tumor or node metastasis when performed after the completion of neoadjuvant treatment in IDC of the breast. New diagnostic modalities utilized at different time points or including a combination of different imaging methods are warranted.