Yaxin Guo ^1,2 Shunian Li ^1,2 Jun Liao ^1,2 Yuqi Guo ³ Yiyan Shang ^2,4 Yunxia Wang ^2,4 Qingxia Wu ⁵ Yaping Wu ^1,2 Meiyun Wang ^1,2 Hongna Tan ^1,2*

• ¹ Department of Radiology, People's Hospital of Zhengzhou University, Zhengzhou, Henan Province, China
• ² Department of Radiology, Henan Provincial People's Hospital, Zhengzhou, Hunan Province, China
• ³ Department of Hepatobiliary and Pancreatic Surgery, People's Hospital of Zhengzhou University & Henan Provincial People’s Hospital, zhengzhou, China
• ⁴ Department of Radiology, People's Hospital of Henan University, zhengzhou, China
• ⁵ Beijing United Imaging Research Institute of Intelligent Imaging, beijing, China

: A total of 593 breast cancer patients who underwent preoperative breast MRI from Jan 2017 to Dec 2020 were enrolled, which were randomly divided into the training (n=474) and test sets (n=119) at the ratio of 8:2. Intratumoral region (ITR) of interest were manually delineated, and peritumoral regions of 3 mm and 5 mm (PTR-3 mm and PTR-5 mm) were automatically obtained by dilating the ITR. Intratumoral and peritumoral radiomics features were extracted from the fat-suppressed T2-weighted images, including first-order statistical features, shape features, texture features, and filtered features. The Mann-Whitney U Test, Z score normalization, K-best method, and least absolute shrinkage and selection operator (LASSO) algorithm were applied to select key features to construct radscores based on ITR, PTR-3 mm, PTR-5 mm, ITR+PTR-3 mm and ITR+ PTR-5 mm. Risk factors were selected by univariate and multivariate logistic regressions and were used to construct a clinical model and a clinical-radiomics model that presented as a nomogram. The performance of models was assessed by sensitivity, specificity, accuracy, the area under the curve (AUC) of receiver operating characteristic (ROC), calibration curves, and decision curve analysis (DCA).Results: ITR+PTR-3 mm radsore and histological grade were selected as risk factors.A clinical-radiomics model was constructed by adding ITR+PTR-3mm radscore to the clinical factor, which was presented as a nomogram. The clinical-radiomics nomogram showed the highest AUC (0.873), sensitivity (72.3%), specificity (78.9%) and accuracy (77.0%) in the training set and the highest AUC (0.851), sensitivity (71.4%), specificity (79.8%) and accuracy (77.3%) in the test set. DCA showed that the clinical-radiomics nomogram had the greatest net clinical benefit compared to the other models.The clinical-radiomics nomogram showed promising clinical application value in differentiating luminal and non-luminal breast cancer.