胸腺上皮性肿瘤18F-FDG PET/CT显像最大标准化摄取值与WHO病理分型及Masaoka分期的关系

Relationship between the maximum standardized uptake value of18F-FDG PET/CT and WHO pathological classification and Masaoka stage of thymic epithelial tumors

目的探讨胸腺上皮性肿瘤(TET)术前18F-FDG PET/CT显像最大标准化摄取值(SUVmax)与世界卫生组织(WHO)病理分型及Masaoka分期的关系。方法回顾性分析2007年9月至2019年3月于南京医科大学第一附属医院经手术病理学结果证实的40例TET患者的临床资料,其中男性14例、女性26例,年龄32~79岁。分析所有患者的术前18F-FDG PET/CT显像资料,测定病灶的SUVmax。参照WHO(2015) TET病理分型将TET患者分为低危型胸腺瘤(A、AB、B1型)、高危型胸腺瘤(B2、B3型)和胸腺癌(C型)3组;采用Masaoka分期标准将TET患者分为Ⅰ期、Ⅱ期和Ⅲ期3组;将TET患者分为胸腺瘤(包括低危型胸腺瘤和高危型胸腺瘤)和胸腺癌2组,采用受试者工作特征(ROC)曲线计算SUVmax和曲线下面积(AUC )。3组间的比较采用Kruskal-Wallis秩和检验,2组间的比较采用Mann-Whitney U检验。结果低危型胸腺瘤11例(A型1例、AB型4例、B1型6例),高危型胸腺瘤15例(B2型10例、B3型5例),胸腺癌14例。Masaoka分期:Ⅰ期8例,Ⅱ期17例,Ⅲ期15例。低危型胸腺瘤、高危型胸腺瘤和胸腺癌的中位SUVmax分别为3.78、5.21和10.44 ,3组间SUVmax的差异有统计学意义(χ2=26.716 ,P<0.01);组间的两两比较差异均有统计学意义(Z=3.088、-3.928、4.106,均P< 0.01)。Ⅰ期、Ⅱ期、Ⅲ期的中位SUVmax分别为3.74、5.14、10.08,3组间SUVmax的差异有统计学意义(χ2=22.295 ,P<0.01),组间的两两比较差异均有统计学意义(Z=2.680、3.679、-3.644 ,均P<0.01)。ROC曲线分析结果:AUC为0.953 (95%可变区间:0.891~1.000,P<0.01);SUVmax=6.81是鉴别诊断胸腺瘤与胸腺癌的最佳临界值。结论 18F-FDG PET/CT的参数SUVmax与TET的WHO病理分型及Masaoka分期具有较好的相关性,可为临床制定治疗计划提供参考。

Objective To investigate the relationship between the maximum standardized uptake value(SUVmax)of preoperative18F-FDG PET/CT and the World Health Organization(WHO)pathological classification and Masaoka stage of thymic epithelial tumors.Methods A total of 40 patients(14 males and 26 females ranging in age from 32 years to 79 years)was retrospectively reviewed with histologically proven thymic epithelial tumors who underwent 18F-FDG PET/CT before surgical resection at the First Affliated Hospital of Nanjing Medical University from September 2007 to March 2019.SUVmax was measured.The patients were divided into three groups in accordance with a simplified pathological classification scheme WHO(2015):low-risk thymomas(types A,AB,and B1),high-risk thymomas(types B2 and B3),and thymic carcinomas(type C).In addition,all tumors were divided into three groups on the basis of the Masaoka stage:stagesⅠ,Ⅱ,andⅢ.The area under the curve(AUC)calculated via receiver operating characteristic(ROC)curve analysis was used to estimate the best value of SUVmax that was capable of discriminating thymomas from thymic carcinomas.Groups were compared by using the Mann-Whitney test or Kruskal-Walis test.Results A total of 11 low-risk thymomas(1 type A,4 type AB,and 6 type B1),15 high-risk thymomas(10 type B2 and 5 type B3),and 14 thymic carcinomas were identified.Eight,17,and 15 patients were in Masaoka stagesⅠ,Ⅱ,andⅢ,respectively.The median SUVmax value was 3.78 for low-risk thymomas,5.21 for high-risk thymomas,and 10.44 for thymic carcinomas and was significantly different among groups(Z=3.088,-3.928,4.106;all P<0.01),the difference in SUVmax between the 3 groups is statistically significant(χ2=26.716,P<0.01).The values for Masaoka stagesⅠ,Ⅱ,andⅢwere 3.74,5.14,and 10.08,respectively,and showed significant differences when compared with each other(Z=2.680,3.679,-3.644;all P<0.01),the difference in SUVmax between the 3 groups is statistically significant(χ2=22.295,P<0.01).The results of ROC curve analysis showed that the AUC of SUVmax was 0.953(95%confidence interval:0.891-1.000,P<0.01).SUVmax=6.81 was the best threshold for the differential diagnosis of thymomas and thymic carcinomas.Conclusions SUVmax measured by BF-FDG PET/CT had a good correlation with the pathological classification and Masaoka stage of thymic epithelial tumors.Therefore,it can provide reference value for planning clinical treatment.