Predictive role of 18F-FDG PET/CT in neoadjuvant therapy response in breast cancer with axillary metastasis

Abstract

Objective

The aim of this study is to investigate whether it is possible to predict the response to neoadjuvant therapy (NAT) in axillary lymph node metastasis of breast cancer patients using parameters from ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) scans, and to evaluate the correlation of post-NAT PET/CT findings with axillary histopathology results.

Materials and methods

Breast cancer patients with axillary lymph node involvement, who underwent staging and post-NAT PET/CT, followed by surgery or histopathological evaluation, were included. Metabolic and volumetric ¹⁸F-FDG PET/CT parameters were analyzed to determine their predictive value for NAT response. Receiver operating characteristic (ROC) curves and Chi-square tests were used for statistical evaluation.

Results

Forty-three breast cancer patients were included in the study. Statistically significant differences were observed between the axillary pathology-negative and positive patient groups for the following variables: post-NAT SUVmax (primary and axilla), ΔSUVmax% (primary and axilla), the largest lymph node diameter on staging PET/CT, and the change in diameter of the same lymph node post-NAT. In the post-NAT axillary lymph node visual evaluation, the sensitivity, specificity, the positive predictive value (PPV), and the negative predictive value (NPV) for detecting metastatic axillary lymph nodes on PET/CT, based on pathology results, were calculated as 81.8%, 66.7%, 72%, and 77.7%, respectively. When a 92.38% threshold value was determined for ΔSUVmax% (axilla), they were 90.9%, 42.9%, 62.5%, and 81.8%, respectively.

Conclusion

Metabolic parameters obtained from ¹⁸F-FDG PET/CT can contribute to predicting the treatment response for axillary metastases. ¹⁸F-FDG PET/CT provides insights into the necessity of sentinel lymph node biopsy (SLNB) and axillary dissection. However, due to ¹⁸F-FDG PET/CT's inability to achieve sufficient sensitivity and specificity, it is unlikely to replace SLNB.