Classification Of Breast Edema On T2-weighted Imaging For Predicting Sentinel Lymph Node Metastasis And Biological Behavior In Breast Cancer

Objective: To determine whether preoperative classification of breast edema on T2-weighted imaging(T2WI)is useful for predicting sentinel lymph node(SLN)metastasis and biological behavior in patients with breast cancer,and access whether edema is different in each expression states of human epidermal growth factor receptor 2(HER2).Methods: This retrospective study involved women with breast cancer who underwent preoperative breast MRI and X-ray from January 2019 to March 2022 in Yijishan Hospital of Wannan Medical College.The breast MRI and X-ray findings were recorded according to the Bi RADS Fifth Edition.Breast edema was scored on a scale of 1 to 4 on T2WI(1,no edema;2,peritumoral edema;3,prepectoral edema;and 4,subcutaneous edema).Clinicopathologic data including age,menstrual status,histological grade,estrogen receptors(ER)status,progesterone hormonal receptors(PR)status,HER2 status,Ki-67 expression and SLN status were also recorded.According to the pathological results,the patients were divided into SLN positive and negative,HER2 positive and negative group,and the HER2 negative group was further divided into low expression group and zero expression group.The clinicopathological and imaging differences between the groups were compared.A logistic regression model was used for univariate and multivariate analyses.The univariable analysis of significant variables(p < 0.05)was further applied for the multivariable analysis.ROC curves were built,and the AUC was calculated to compare the predictive ability of each model for SLN metastasis.The relationship between breast edema score(BES)and tumor invasiveness was examined by Spearman’s rank correlation coefficient.Results: In total,341 women were enrolled in the study,among whom 183(54%)showed SLN metastasis.Pathological results showed that there were 80 HER2 positive cases and 261 HER2 negative cases,respectively.In HER2 negative group,there were 92 zero expression cases and 169 low expression cases,respectively.Logistic regression analysis showed that breast edema was an independent risk factor for SLN metastasis.The combined BES model significantly improved the predictive performance of SLN metastasis compared with the clinicopathological model alone(AUC,0.77 vs.0.71;p = 0.005).In addition,the BES was significantly positively correlated with the tumor diameter(p< 0.001),histologic grade(p = 0.001),Ki-67 index(p< 0.001),and non-luminal subtypes(p< 0.001).There were significant differences in ER,PR,Ki-67 status,tumor enhancement pattern,dynamic enhancement curve,diameter,T2 WI edema,BES and suspected calcification between HER2 positive group and HER2 negative group.In HER2 negative group,the low expression tumors showed higher histological grade and more SLN metastasis than those of zero expression,but there was no significant difference in image features.Conclusion: The BES based on T2 WI is useful for predicting SLN metastasis.A higher grade of breast edema is associated with breast cancer aggressiveness and increases the probability of SLN metastasis,and breast edema also helps to predict the expression status of HER2.