The Research On The Predictive Value Of The Nomograme Based On Partial Tumoral Characteristics To Predict Initial Positive Margins In BCS

Purpose:To investigate the preoperative predictive value of the histogram based on microcalcification,perivascular,ductal lesions and Ki-67 tumor features on the positive rate of the first surgical margin in breast conserving patients,so as to provide help to improve the rate of initial negative margins so as to minimize the rate of re-excision and further surgery in BCS.Methods:Retrospective analyses of the data of 337 eligible breast cancer patients who received BCS treatment from January 2018 to May 2020 were conducted.This study performed intraoperative analyses of margins using frozen section analysis on all the patients.The patients were randomly divided into the modeling group(n=236)and the validation group(n=101)in a 7:3ratio.This study analyzed the influencing factors for initial positive surgical margins according to the results of univariate and multivariate analyses in the modeling group.And after the correlation matrix analysis of the influencing factors,they were included into a nomogram which was established to predict the rate of initial positive surgical margins.The accuracy and performance of the nomogram to predict the rate of initial positive margins were tested with calibration curve and coincident indicator in the modeling group and the validation group respectively.Results: The rates of initial positive margins in the modeling group and the validation group were 13.13% and 17.82% respectively.The result of the modeling group showed that microcalcification(OR=0.650,P=0.003),peritumoral blood vessels(OR=0.650,P<0.01),intraductal lesion(OR=0.650,P=0.003),low Ki-67 expression value(OR=0.398,P=0.003)was significantly associated with initial positive margins in breast-conserving surgery.The efficacy of predicting the positive rate of the first incision margin in the model group and the validation group by ROC curve profile: the AUC was 0.866 and0.888,respectively.The fitting degree of calibration curves for the model group and the validation group was respectively: C index was 0.866 and 0.888,and Brier was 0.088 and 0.096.The negative predicted value of the training group(95.9%vs.38.5%)and the validation group(94.4%vs.46.7%)were significantly higher than the positive predicted value.Through ROC curve analysis,the total scores of the nomogram <137 and ≥ 137 were divided into low-risk group and high-risk group respectively.Conclusion: 1.Tumor characteristics including microcalcification,peritumoral blood vessels,intraductal lesion,low Ki-67 expression value are the independent risk factors for initial positive margins in BCS.2.Based on the high degree of the consistency of the predicted values of microcalcification,peritumoral blood vessels,intraductal lesion,Ki-67 expression value in the nomogram with the actual observation values,this study has clinical application value.3.Nomogram can be applied to visually evaluate the rate of initial positive margins in BCS,which is valuable for making individualized operation plans to reduce the rate of re-excision and further surgery.