精确的术前评估乳腺保育手术(BCS)切缘阳性的风险有助于手术计划的制定。在这项多中心验证研究中，我们开发了一种基于MRI的放射组学模型来预测手术切缘状态。我们回顾性收集了三所医院(SYMH，n = 296; SYSUCC，n = 131; TSPH，n = 143)进行BCS患者的术前乳腺MRI。基于放射组学的切缘阳性风险预测模型在SYMH患者上进行训练(训练集和测试集的比例为7:3)，并在SYSUCC和TSPH群体中进行外部验证。该模型能够将患者分为不同亚组，其切缘阳性风险各异。此外，我们使用了免疫-放射组学模型和上皮间质转化(EMT)特征来推断不同切缘状态下免疫细胞和肿瘤细胞EMT状态的分布模式。放射组学模型的AUC分别为0.78(0.66-0.90)、0.88(0.79-0.96)和0.76(0.68-0.84)在测试队列和两个外部验证队列中。低风险和高风险亚组的实际切缘阳性率分别在0-10%和27.3-87.2%之间。阳性手术切缘与肿瘤区EMT水平和B细胞浸润，以及围肿瘤区B细胞、未成熟树突状细胞和中性粒细胞浸润的富集有关。该基于MRI的预测模型可以作为可靠的工具预测BCS的切缘阳性风险。肿瘤免疫微环境的改变与手术切缘状态相关。该研究可以协助BCS的术前计划。进一步研究不同切缘状态下肿瘤免疫微环境的内在机制，有望开发新的切缘评估指标并揭示其内在机制。• 基于MRI的放射组学预测模型(CSS模型)通过提取多个序列和段的特征，可以估计乳腺保育手术的切缘阳性风险。• CSS模型的放射组学得分可以对进行乳腺保育手术的患者进行风险分层，从而有助于手术计划。• 借助基于MRI的放射组学来估计免疫微环境的组成，我们首次发现乳腺保育手术切缘状态与微环境中免疫细胞的浸润和乳腺肿瘤细胞的EMT状态相关。 一一© 2023. The Author(s), 由欧洲放射学学会独家许可。

Accurate preoperative estimation of the risk of breast-conserving surgery (BCS) resection margin positivity would be beneficial to surgical planning. In this multicenter validation study, we developed an MRI-based radiomic model to predict the surgical margin status.We retrospectively collected preoperative breast MRI of patients undergoing BCS from three hospitals (SYMH, n = 296; SYSUCC, n = 131; TSPH, n = 143). Radiomic-based model for risk prediction of the margin positivity was trained on the SYMH patients (7:3 ratio split for the training and testing cohorts), and externally validated in the SYSUCC and TSPH cohorts. The model was able to stratify patients into different subgroups with varied risk of margin positivity. Moreover, we used the immune-radiomic models and epithelial-mesenchymal transition (EMT) signature to infer the distribution patterns of immune cells and tumor cell EMT status under different marginal status.The AUCs of the radiomic-based model were 0.78 (0.66-0.90), 0.88 (0.79-0.96), and 0.76 (0.68-0.84) in the testing cohort and two external validation cohorts, respectively. The actual margin positivity rates ranged between 0-10% and 27.3-87.2% in low-risk and high-risk subgroups, respectively. Positive surgical margin was associated with higher levels of EMT and B cell infiltration in the tumor area, as well as the enrichment of B cells, immature dendritic cells, and neutrophil infiltration in the peritumoral area.This MRI-based predictive model can be used as a reliable tool to predict the risk of margin positivity of BCS. Tumor immune-microenvironment alteration was associated with surgical margin status.This study can assist the pre-operative planning of BCS. Further research on the tumor immune microenvironment of different resection margin states is expected to develop new margin evaluation indicators and decipher the internal mechanism.• The MRI-based radiomic prediction model (CSS model) incorporating features extracted from multiple sequences and segments could estimate the margin positivity risk of breast-conserving surgery. • The radiomic score of the CSS model allows risk stratification of patients undergoing breast-conserving surgery, which could assist in surgical planning. • With the help of MRI-based radiomics to estimate the components of the immune microenvironment, for the first time, it is found that the margin status of breast-conserving surgery is associated with the infiltration of immune cells in the microenvironment and the EMT status of breast tumor cells.© 2023. The Author(s), under exclusive licence to European Society of Radiology.