摘要目的 探讨新辅助化疗(NAC)前后乳腺背景实质强化(BPE)的特征及变化规律,以及BPE预测NAC后早期疗效的价值.方法 回顾性分析2014年8月至2016年12月复旦大学附属肿瘤医院,经术前穿刺活检及NAC后手术病理证实为单侧乳腺癌,且NAC前、NAC第2个周期结束后均进行了MRI检查的161例女性患者.所有患者均行双侧乳腺平扫及增强扫描.2名医生分别阅片,根据乳腺影像报告和数据系统标准对乳腺癌对侧乳腺的BPE进行定性评价(极少、轻度、中度和重度).根据NAC后行手术病理检查结果,将患者分为病理完全缓解(pCR)组和非pCR组.记录NAC前,经穿刺检测肿瘤内雌激素受体(ER)、孕激素受体(PR)和人表皮生长因子受体(HER2)的表达情况.采用独立样本t检验与χ2检验比较pCR组与pCR组临床资料的差异,采用Kappa检验评价2名医师对BPE分类评价的一致性,采用Wilcoxon检验NAC前、后的BPE分类差异,采用Mann-Whitney U检验比较绝经前、后的BPE分类差异,采用Binary logistic回归分析疗效的相关因素.结果 NAC后经手术病理证实,pCR组59例,非pCR组102例.pCR和非pCR组间,年龄、病灶最大径、病灶大小分布、绝经状态、治疗前淋巴结差异均无统计学意义(P均>0.05),ER或PR、HER2状态差异有统计学意义(P均<0.05).2名医师对治疗前和治疗后BPE定性评估的Kappa值分别为0.644和0.708,一致性为中等和好.NAC治疗前和治疗后,绝经前组BPE均明显高于绝经后组,差异有统计学意义(P均<0.01).161例患者中,NAC治疗后106例BPE减低(绝经前组60例、绝经后组46例),55例无变化(绝经前组27例、绝经后组28例),治疗前后的总体BPE差异有统计学意义(Z=9.439,P<0.01),绝经前组与绝经后组,治疗前后的BPE差异均有统计学意义(Z值分别为6.958、6.256,P均<0.05).logistic多因素回归模型显示,NAC后BPE的变化、ER或PR、HER2状态是影响疗效达到pCR的独立因素.结论 无论绝经前、后女性,BPE在NAC后会出现不同程度的降低,并且BPE降低可作为NAC疗效评估的独立因素.

abstractsObjective To retrospectively investigate the characteristics of background parenchymal enhancement(BPE)in the contralateral breast following neoadjuvant chemotherapy(NAC)and whether BPE could help predict tumor response in early stage of advanced breast cancer. Methods Data from 161 patients who were diagnosed with unilateral breast cancer and then underwent NAC before surgery were analyzed retrospectively from August 2014 to December 2016.All the patients underwent both bilateral breast MRI scan with contrast enhancement. Two experienced radiologists independently categorized the patients' levels of BPE into four categories (1=minimal, 2=mild, 3=moderate, 4=marked) at baseline and after the 2nd cycle of NAC. All the patients were divided in to pathologic complete response (pCR) group and non-pCR group according to the histopathologic tumour response.The status of estrogen receptor(ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) were recorded before underwent NAC.The t test and Pearson chi-squared test were used to compare the baseline characteristics of the pCR and Non-pCR groups.The kappa test was used to test the inter-observer agreement.The Wilcoxon test was used to test for changes of BPE categories after NAC.The Mann-Whitney U test was used to test the difference of BPE between pre-and post-menopausal status. Associations were evaluated using Binary logistic regression models. Results Fifty nine patients achieved pCR, and 102 patients had residual disease (non-pCR). Age, tumor size, distribution of size, menopausal status and lymph node showed no significance between pCR and non-pCR groups(all P>0.05),while only ER/PR status and HER2 status had a significant difference (P>0.05 in both). Inter-observer agreement regarding BPE categorization was moderate and substantial before and after NAC(Kappa value 0.644 and 0.708).The level of BPE was higher in premenopausal than post-menopausal women both at baseline and after the 2nd cycle of NAC(P<0.01). Decreased BPE was observed in 106 cases(premenopausal 60 cases and postmenopausal 46 cases),and no change in BPE were observed in 55 cases (premenopausal 27 cases and postmenopausal 28 cases). A significant reduction in BPE was observed after the 2nd NAC cycle in the overall cases, pre-and post-menopausal cases (all P<0.01). Logistic model showed that hormonal receptor (HR) negative and HER-2 receptor at baseline and the change of BPE after NAC were the independent factors for predicting pCR. Conclusions Regardless of the menopausal status, BPE showed a reduction after NAC, and it can serve as an additional imaging biomarker of tumour response at an early stage of NAC.