摘要Background This multicenter prospective study aimed to assess the utility of dynamic enhanced magnetic resonance imaging (MRI) prior to breast-conserving surgery for breast cancer.Methods The research subjects were drawn from patients with primary early resectable breast cancer treated in the breast disease centers of six three-level hospitals in Beijing from 1 January 2010 to 31 December 2012.The participants were allocated to a breast-conserving surgery group (breast-conserving group) or a total mastectomy group (total mastectomy group).Enhanced MRI was used to measure breast volume,longest diameter of tumor and tumor volume.The correlations between these measurements and those derived from histopathologic findings were assessed.The relationships between the success rate of breast-conserving surgery and MRI-and pathology-based measurement results were statistically analyzed in the breast-conserving group.Results The study included 461 cases in the total mastectomy group and 195 in the breast-conserving group.Allocation to these groups was based on clinical indications and patient preferences.The cut-off for concurrence between MRI-and pathology-based measurements of the longest diameter of tumor was set at 0.3 cm.In the total mastectomy group,the confidence interval for 95％ concurrence of these measurements was 35.41％-44.63％.Correlation coefficients for MRI and histopathology-based measurements of breast volume,tumor volume and tumor volume/breast volume ratio were r=0.861,0.569,and 0.600,respectively (all P ＜0.001).In the breast-conserving group,with 0.30 cm taken as the cut-off for concurrence,the 95％ confidence interval for MRI and pathology-based measurements of the longest diameter of tumor was 29.98％-44.01％.The subjective and objective success rates for breast-conserving surgery were 100％ and 88.54％,respectively.Conclusions There were significant correlations between dynamic enhanced MRI-and histopathology-based measurements of the longest diameter of breast lesions,breast and tumor volumes,and breast volume/tumor volume ratios.Preoperative MRI examination improves the success rate of breast-conserving surgery.