18F-FDG PET/CT在鉴别胸腺上皮肿瘤组织学分型中的应用

Value of 18F-FDG PET/CT in WHO classification of thymic epithelial neoplasms

目的研究2-氟-18-氟-2-脱氧-D-葡萄糖(18F-FDG)PET/CT影像表现在鉴别胸腺上皮肿瘤组织学分型中的作用。方法选取2011年1月1日至2018年6月30日北京大学肿瘤医院48例经穿刺活检或肿瘤切除术后病理证实为上皮性胸腺肿瘤的初诊患者作为研究对象,回顾性分析患者全身18F-FDGPET/CT图像资料,采用双变量相关性分析、t检验和受试者工作特征(ROC)曲线分析法,比较患者临床病理特征、CT特点和代谢情况的差异。结果48例患者低危胸腺瘤组17例、高危胸腺瘤组8例、胸腺癌组23例,淋巴结转移12例,胸膜转移4例,肺转移3例,肝、心包、骨转移各2例。3组患者有无包膜(r=0.921,P<0.001),有无中纵隔(r=0.452,P=0.001)或周围侵犯(r=0.865,P=0.000),有无淋巴结转移(r=0.505,P<0.001)或远处脏器转移(r=0.383,P=0.008)、SUVmax值(t=0.626,P<0.001)、SUVmax/病变最大径值(t=0.645,P<0.001)等方面比较,差异均具有统计学意义。ROC曲线分析示区分低危组与高危或胸腺癌组准确性较高的指标分别为病变周围侵犯情况、SUVmax/病变最大径和SUVmax,ROC曲线下面积分别为0.952、0.916和0.865。结论18F-FDG PET/CT可用于鉴别胸腺上皮肿瘤组织学分型,可有效区分低危组胸腺瘤与高危组胸腺瘤或胸腺癌。

Objective To assess the value of 18F-FDG PET/CT imaging in the differential WHO classification of thymic epithelial neoplasms. Methods From February 1, 2011 to June 30, 2018, 48 patients with pre-therapy thymic epithelial neoplasms confirmed by surgery or biopsy at Peking University Cancer Hospital were included and divided into three groups: low-risk thymomas, high-risk thymomas, and thymic carcinomas. Bivariate correlation analysis, Student's t test, and ROC curve analysis were used to analyze and compare the clinicopathologic features, features of CT imaging, and FDG metabolism parameters among the three groups of thymic epithelial neoplasms. Results Of 48 cases of thymic epithelial neoplasms, 17 were low-risk thymomas, 8 were high-risk thymomas, 23 were thymic carcinomas, 12 had lymph node metastasis, 4 had pleural metastasis, 3 had pulmonary metastasis, and 2 had liver/pericardium/bone metastasis. Tumor capsule (r=0.921, P<0.001), mediastinal invasion (r=0.452, P=0.001), neighboring structure invasion (r=0.865, P<0.001), lymph node metastasis (r=0.505, P<0.001), distant organ metastasis (r=0.383, P=0.008), SUVmax (t=0.626, P<0.001), and SUVmax/maximum tumor diameter ratio (t=0.645, P<0.001) were significantly different among the three groups (P<0.01). Neighboring structure invasion, SUVmax/maximum tumor diameter ratio, and SUVmax were found to be most useful predictive factors to distinguish low-risk thymomas from high-risk thymomas or thymic carcinomas (areas under the ROC curves were 0.952, 0.916, and 0.865, respectively). Conclusion 18F-FDG PET/CT can be used to identify different WHO classifications of thymic epithelial neoplasms, and can effectively distinguish low-risk thymomas from high-risk group thymomas or thymic carcinomas.