An MRI-Based Radiomics Nomogram to Distinguish Ductal Carcinoma In Situ with Microinvasion From Ductal Carcinoma In Situ of Breast Cancer

•Accurate preoperative differentiation between DCISM and DCIS can facilitate individualized treatment optimization. •A radiomics nomogram based on preoperative MR images demonstrated the best discrimination efficacy between DCISM and DCIS. •BPE was an independent clinical risk factor for differentiating DCISM from DCIS. Rationale and Objectives Accurate preoperative differentiation between ductal carcinoma in situ with microinvasion (DCISM) and ductal carcinoma in situ (DCIS) could facilitate treatment optimization and individualized risk assessment. The present study aims to build and validate a radiomics nomogram based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) that could distinguish DCISM from pure DCIS breast cancer. Materials and Methods MR images of 140 patients obtained between March 2019 and November 2022 at our institution were included. Patients were randomly divided into a training (n = 97) and a test set (n = 43). Patients in both sets were further split into DCIS and DCISM subgroups. The independent clinical risk factors were selected by multivariate logistic regression to establish the clinical model. The optimal radiomics features were chosen by the least absolute shrinkage and selection operator, and a radiomics signature was built. The nomogram model was constructed by integrating the radiomics signature and independent risk factors. The discrimination efficacy of our nomogram was assessed by using calibration and decision curves. Results Six features were selected to construct the radiomics signature for distinguishing DCISM from DCIS. The radiomics signature and nomogram model exhibited better calibration and validation performance in the training (AUC 0.815, 0.911, 95% confidence interval [CI], 0.703–0.926, 0.848–0.974) and test (AUC 0.830, 0.882, 95% CI, 0.672–0.989, 0.764–0.999) sets than in the clinical factor model (AUC 0.672, 0.717, 95% CI, 0.544–0.801, 0.527–0.907). The decision curve also demonstrated that the nomogram model exhibited good clinical utility. Conclusion The proposed noninvasive MRI-based radiomics nomogram model showed good performance in distinguishing DCISM from DCIS. Accurate preoperative differentiation between ductal carcinoma in situ with microinvasion (DCISM) and ductal carcinoma in situ (DCIS) could facilitate treatment optimization and individualized risk assessment. The present study aims to build and validate a radiomics nomogram based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) that could distinguish DCISM from pure DCIS breast cancer. MR images of 140 patients obtained between March 2019 and November 2022 at our institution were included. Patients were randomly divided into a training (n = 97) and a test set (n = 43). Patients in both sets were further split into DCIS and DCISM subgroups. The independent clinical risk factors were selected by multivariate logistic regression to establish the clinical model. The optimal radiomics features were chosen by the least absolute shrinkage and selection operator, and a radiomics signature was built. The nomogram model was constructed by integrating the radiomics signature and independent risk factors. The discrimination efficacy of our nomogram was assessed by using calibration and decision curves. Six features were selected to construct the radiomics signature for distinguishing DCISM from DCIS. The radiomics signature and nomogram model exhibited better calibration and validation performance in the training (AUC 0.815, 0.911, 95% confidence interval [CI], 0.703–0.926, 0.848–0.974) and test (AUC 0.830, 0.882, 95% CI, 0.672–0.989, 0.764–0.999) sets than in the clinical factor model (AUC 0.672, 0.717, 95% CI, 0.544–0.801, 0.527–0.907). The decision curve also demonstrated that the nomogram model exhibited good clinical utility. The proposed noninvasive MRI-based radiomics nomogram model showed good performance in distinguishing DCISM from DCIS.