Computed tomography reconstruction for evaluating response in axillary lymph nodes of breast cancer after neoadjuvant chemotherapy.

PURPOSE: To assess the performance of computed tomography (CT) reconstruction in evaluating the response in metastatic lymph nodes after neoadjuvant chemotherapy (NAC) in breast cancer patients.

METHODS: Patients undergoing pre-NAC and post-NAC CT were identified from the Peking University Cancer Hospital database. Axillary Lymph nodes (ALNs) that shrunk to < 5 mm in short-axis diameter after NAC on CT reconstruction images were classified as clinical complete response. Evaluations of CT reconstruction on ALNs were correlated with residual nodal disease in the final pathology. Overall, 53 invasive breast cancer patients between October 2016 and March 2018 were eligible for our study. The median age was 48 (range 35-70) years. Most women presented with T2 tumors (35/53, 66.0%).

RESULTS: After NAC, 20 (37.7%) patients without residual nodal disease were defined as pCR. Of 53 patients, 18 (33.9%) showed negative conversion of ALNs on CT reconstruction evaluation; axillary pCR was present in 16/18 (88.9%) patients. Among 35 patients with abnormal nodes on post-NAC CT reconstruction, 31 (88.6%) had axillary metastasis on the final pathology. The sensitivity and specificity of CT reconstruction in predicting node-negative status were 80.0% and 93.9%, respectively. The positive predictive value was 84.9% for lymph node pCR. The area under the receiver operating characteristic curve of each imaging modality was 0.870 (95% confidence interval 0.755-0.984).

CONCLUSIONS: CT reconstruction was useful for evaluating ALNs response following NAC and may be used to predict axillary nodes' pCR with adequate accuracy.