骨肉瘤术前化疗效果的MRI评估

The evaluation of MRI imaging in monitoring the response of osteosarcoma to preoperative neoadjuvant chemotherapy

目的应用MRI评估骨肉瘤术前化疗的效果。方法回顾性研究2003年6月至2006年5月间接受了新辅助化疗+手术切除+术后化疗的标准治疗的45例原发初治无转移的四肢成骨肉瘤患者。于术前化疗前后分别行病变部位的MRI检查,所有切除标本进行病理坏死率分析。将化疗前后MRI信号的改变,肿瘤的体积变化等与患者的肿瘤坏死率以及预后相比较。通过统计学方法找出相关的因素。结果化疗后MRI影像出现4种表现:暗色区域、点片状区域提示化疗反应较好,出现均质性改变和囊性改变的区域化疗反应较差,但骨肉瘤整体的影像变化与坏死率无统计学相关性;应用MRI测量的肿瘤体积变化与坏死率相关。结论应用MRI影像变化评估骨肉瘤新辅助化疗效果有一定意义。应用MRI测量体积,化疗后肿瘤体积减小提示肿瘤坏死率较高,化疗前后肿瘤的体积变化与坏死率相关(P=0.019),可以预测骨肉瘤的化疗效果,推测患者的预后。

Objective To evaluate the practicability of MRI imaging in monitoring the response of osteosarcoma to preopertive neoadjuvant chemotherapy. Methods A homogeneous group of 45 patients were admitted into People＇s Hospital Muscularskeletal Tumor Center of Peking University between June 2003 and May 2006. All patients sustained primary osteosarcoma in limbs with no metastasis, and were retrospectively evaluated in terms of MRI imaging, histologic response to preoperative treatment. They underwent a standardized treatment of new neoadjuvant chemotherapy, tumor resection and postoperative chemotherapy. MRI imaging was performed on the foci before and after the chemotherapy. Pathological necrosis rate was analyzed on all removed samples. We compared the change of MRI signal and the size of the tumor with the necrosis rate and to find out the related factors related to the prognosis. Results The changes of MRI finding may be classified as following four patterns： mottled and speckled area indicating good response to the chemotherapy; homogeneous and cystic-like area indicating poor response. However those image changes do not statistically correspond to tumor necrosis rate which correspond to the change of tumor size. Conclusions MRI imaging is relatively significant in evaluating the response of preoperative chemotherapy. The shrinkage of tumor demonstrated that the necrosis rate is high. The change of the tumor size correlates with necrosis rate （P=0.019）. The tumor＇s response to chemotherapy and the prognosis can be estimated through the measures of size changes and the analysis of necrosis rate.