Abstract: Objective  To explore the factors associated with complete resolution of sentinel lymph node metastasis (pCR) after neoadjuvant chemotherapy in breast cancer and to establish a predictive model.Methods The medical records of 136 female patients with breast cancer who received neoadjuvant chemotherapy in the First Hospital of Lanzhou University from January 2022 to February 2024 were retrospectively analyzed.According to the 80/20 rule,the patients were randomly divided into a training set (108 cases) and a validation set (28 cases).Based on the pathological examination results of axillary lymph node dissection (ALND) after neoadjuvant chemotherapy in breast cancer patients,they were classified into the sentinel lymph node pCR group and non-pCR group.Multivariate logistic regression analysis was used to screen the independent risk factors of sentinel lymph nodes failing to reach pCR.Build a nomogram prediction model based on the screened risk factors.By drawing the receiver operating characteristic(ROC) curve calculation curve, the area under ROC curve, sensitivity and specificity are used to evaluate the discrimination of the model.Results Among the 108 breast cancer patients,46 cases achieved pCR in the sentinel lymph nodes,accounting for 42.59% (46 cases/108 cases).In addition,33 cases (30.56%) achieved pCR in the primary tumor lesion.The non-pCR group showed a higher proportion of stage Ⅲ clinical staging,lymph node short-axis reduction of less than 50% before and after treatment,tumor maximum diameter reduction of less than 50% before and after treatment,lymph node type Ⅲ classification,and blood flow grade Ⅲ compared to the pCR group (P<0.05).Multivariate logistic regression analysis showed that Clinical staging (OR=3.593,95%CI:1.276~10.121),lymph node short-axis reduction of less than 50% before and after treatment (OR=4.272,95%CI:1.517~12.032),tumor maximum diameter reduction of less than 50% before and after treatment (OR=3.710,95%CI:1.317~10.449),lymph node type (OR=3.827,95%CI:1.359~10.779),and blood flow grade (OR=4.764,95%CI:1.691~13.418) were identified as risk factors for not achieving pCR in the sentinel lymph nodes after neoadjuvant chemotherapy in breast cancer patients (P<0.05).The sensitivity of the risk model for predicting non-achievement of pCR in the sentinel lymph nodes after neoadjuvant chemotherapy in the training set of breast cancer patients was 0.826 (95%CI:0.705~0.943),with a specificity of 0.826 (95%CI:0.712~0.919) and an area under the ROC curve of 0.847 (95%CI:0.738~0.952).In the validation set,the sensitivity for predicting non~achievement of pCR in the sentinel lymph nodes after neoadjuvant chemotherapy in breast cancer patients was 0.731 (95%CI:0.608~0.904),with a specificity of 0.827 (95%CI:0.713~0.941) and an area under the ROC curve of 0.834 (95%CI:0.729~0.951).Conclusion Clinical staging,changes in lymph node short-axis before and after treatment,changes in tumor maximum diameter before and after treatment,lymph node type,and blood flow grade are associated with pCR in the sentinel lymph nodes after neoadjuvant chemotherapy in breast cancer patients.Constructing a predictive model can help evaluate the pCR status of sentinel lymph nodes after neoadjuvant chemotherapy.

Key words: breast cancer, neoadjuvant chemotherapy, sentinel lymph nodes, complete relief, prediction model