动态增强MRI监测乳腺癌新辅助化疗疗效的应用价值

Value of dynamic contrast-enhanced MRI in assessment of chemotherapy in breast cancer

目的 探讨动态增强MRI监测乳腺癌新辅助化疗疗效及评估化疗后残留病灶的价值.方法 对43例患者的44个浸润性导管癌病灶行术前新辅助化疗,分别于化疗前、1个疗程化疗后和化疗结束时行动态增强MRI扫描,比较化疗有效与无效患者的肿瘤组织形态学变化、肿瘤体积变化和血流动力学变化特点.以手术病理为对照,评价术前MRI判断病灶残留情况的效果.结果 44个乳腺癌病灶中,治疗有效36个病灶,无效8个病灶.治疗有效组经1个疗程化疗后,肿瘤体积缩小不明显,化疗结束后肿瘤体积较治疗前明显缩小（P〈0.01）,缩小中位数为18.5 cm3.治疗有效组病灶呈向心型缩小29个,树枝型缩小7个.新辅助化疗前,有效组与无效组的早期强化率（E1）、峰值强化率（Emax）和达峰时间（Tmax）差异均有统计学意义（均P〈0.05）.化疗1个疗程后,有效组的E1和Emax降低,而Tmax升高,与化疗前比较,差异均有统计学意义（均P〈0.01） 而无效组的E1、Emax和Tmax未发生明显变化.新辅助化疗前,有效组的时间信号强度曲线以廓清型、平台型为主（占86.1%） 化疗后,强化峰值明显下降,时间-信号强度曲线转为以持续强化型为主 化疗结束时,持续强化型占63.9%.无效组的时间-信号强度曲线化疗前后变化不大.新辅助化疗后动态增强MRI监测乳腺癌残留病灶与手术病理结果高度相关（r=0.866,P〈0.01）.结论 动态增强MRI可在乳腺癌新辅助化疗疗程中监测瘤体变化,评价、预测新辅助化疗疗效,并可用于术前评估化疗后病灶的残留情况.

Objective To assess the value of dynamic contrast-enhanced MRI （DMRI） in predicting early response to neoadjuvant chemotherapy （ NAC） in patients with locally advanced breast cancer （LABC） and to assess the accuracy of MRI in evaluation of residual disease after NAC. Methods Forty-three women with LABC （44 lesions, all were invasive ductal carcinoma） underwent DMRI before, after the first and final cycles of NAC. For each patient, the tumor volume, early enhancement ratio （E1）, maximum enhancement ratio （Emax） , and maximum enhancement time （Tmax） , dynamic signal intensity-time curve were obtained during treatment. The residual tumor volumes obtained by DMRI were compared with pathological findings to assess the accuracy of DMRI. Results After the first cycle of NAC, the mean volume of responders decreased insignificantly （P = 0.055）, but after NAC, mean volume of residual tumor decreased significantly （ P = 0. 000 ）. Morphological changes： 29 cases showed a concentric shrinkage pattern while 7 cases showed a dendritic shrinkage pattern. Significant differences were found in E1, Emax and Tmax between responders and non-responders （ P 〈 0.05）. After the first cycle of NAC, El, Emax and Tmax of responders changed significantly （P 〈 0. 001 ）, while there was no significant change in non-responders （P〉0. 05）. After NAC, the dynamic signal intensity-time types were changed in responders, and tended to be significantly flattening, while no significant change was found in non-responders. The residual tumor volume correlation coefficient between MRI and pathology measurements was very high （r =0.866, P〈0.01）. Conclusion DMRI is useful to evaluate the early response to NAC in LABC. The presence and volume of residual tumor in LABC patients treated with NAC can be accurately evaluated by DMRI.