DWI对局部进展期乳腺癌新辅助化疗疗效评价的初步研究

Response of Locally Advanced Breast Cancer to Neoadjuvant Chemotherapy:a Pilot Study with Diffusion-weighted MRI

目的:探讨磁共振扩散加权成像(DWI)对局部进展期乳腺癌新辅助化疗疗效评价以及作为预测因子的可行性。方法:根据10例乳腺癌化疗后退缩情况将肿瘤分成缓解和进展两组,比较两组化疗前后ADC值和DWI信号强度的变化,并评价治疗前ADC值与化疗结束肿瘤退缩变化的相关性。结果:无论是治疗前还是治疗后,ADC值和DWI信号强度在缓解组和进展组间差异均无显著性意义(P>0.05),但缓解组治疗后ADC值升高,而进展组则降低,尤其在b=1000和2000s/mm2时明显。b=1000s/mm2时,肿瘤高活性区和低活性区对治疗反应比较显示,肿瘤高活性区ADC值较低,治疗后ADC值升高(1.195±0.230和1.371±0.295);而肿瘤低活性区ADC值较高,治疗后ADC值反而下降(1.632±0.241和1.312±0.297);与病理对照显示,治疗后肿瘤细胞蜕变,并伴有明显的胶元和纤维化形成。治疗前ADC值与治疗后肿瘤退缩呈负相关,当b取1000和2000s/mm2时相关更明显,前者为r=-0.802,P=0.005,后者的r=-0.745,P=0.013。结论:DWI可以对局部进展期乳腺癌新辅助化疗疗效作评价,并能对治疗疗效作出预测。

Objective：To assess the feasibility of using diffusion-weighted MRI for pretreatment prediction and monitoring of tumor response to neoadj uvant chemotherapy in patients with locally advanced breast cancer. Methods：Ten patients were divided into response group and progression group according to the changes of tumor size after chemotherapy. Changes in ADC value and signal intensity （SI） of DWI were compared between the two groups before and after the treatment. Pretreatment ADCs were calculated and compared with posttreatment changes in tumor volumes measured on enhanced MR images by using the Spearman correlation test. Results：The ADC and SI measured before therapy revealed no difference between the response group and progression group （P〉0. 05） ,and nor did the ADC and SI measured after therapy. But the mean ADC value of the posttreatment was increased in the response group,while it was decreased in the progression group, which was especially obvious with the use of b value 1000s/mm^2 or 2000s/mm^2 diffusion-weighted MR imaging. The posttreatment mean ADC value was increased in comparison with the pretreatment mean ADC value in the higher viable tumor regions （b= 1000s/mm^2 ： 1. 371 ± 0. 295 vs 1.195 ± 0.23 ）. Conversely, the posttreatment mean ADC value was reduced in lower viable tumor regions （b= 1000s/mm^2：1. 312± 0. 297 vs 1. 632 ± 0. 241）. These features closely matched the histologic findings such as tumor cells metamorphosis and collagen and fibrosis formation. The strong negative correlation was observed between ADC values,measured prior to treatment,and changes in tumor volumes after therapy,especially when b at 1000s/mm^2 （r = -0. 802,P=0. 005） and 2000s/mm^2 （r=-0. 745 ,P=0. 013） respectively. Conclusion：Diffusion-weighted MR imaging has potential use for detecting response to neoadjuvant chemotherapy in locally advanced breast cancer and for predicting treatment outcome.