摘要目的:探讨 18F-FDG PET显像代谢参数对结直肠癌(CRC)微卫星高度不稳定性(MSI-H)、人表皮生长因子受体2(HER2)表达的预测价值。 方法:回顾性收集南京大学医学院附属鼓楼医院2016年1月至2024年3月收治的101例CRC患者[男58例、女43例，年龄68.0(58.0，75.0)岁]的 18F-FDG PET影像和临床病理资料，其中MSI-H组17例，微卫星稳定性/微卫星低度不稳定性(MSS/MSI-L)组84例；HER2表达组23例，HER2未表达组34例，未行HER2检测者44例。通过单因素分析(两独立样本 t检验、Mann-Whitney U检验、 χ2检验)筛选组间差异有统计学意义的变量进行多因素logistic回归分析，得到独立危险因素，再用ROC曲线评价其预测MSI-H和HER2表达的效能。采用Bootstrap法进行内部验证。 结果:MSI-H组与MSS/MSI-L组肿瘤代谢体积(MTV) 80%分别为2.1(1.6，4.0)和1.4(1.0，2.7) cm 3( Z＝-2.10， P＝0.036)，这2组间病灶糖酵解总量(TLG) 80%、癌胚抗原(CEA)差异也有统计学意义( Z＝-2.27， χ2＝6.40，均 P<0.05)。HER2表达组与HER2未表达组TLG 80%分别为29.0(16.1，41.0)和14.3(9.4，22.9) g ( Z＝-2.80， P＝0.005)，2组间MTV 80%、异质性指数(HI)和 CV差异也有统计学意义( Z＝-2.24， t值：-2.26、2.54，均 P<0.05)。多因素logistic回归分析示，MSI-H的独立危险因素为MTV 80%[比值比( OR)＝1.326(95% CI：1.015～1.733)， P＝0.038]与CEA[ OR＝0.200(95% CI：0.056～0.706)， P＝0.012]；ROC曲线分析示，二者联合预测MSI-H的AUC为0.730(95% CI：0.605～0.856)，内部验证一致性指数(C-index)为0.716；HER2表达的独立危险因素为TLG 80%[ OR＝1.037(95% CI：1.001～1.073)， P＝0.041]与 CV[ OR＝1.467(95% CI：1.073～2.005)， P＝0.016]，二者联合预测HER2表达的AUC为0.775(95% CI：0.645～0.875)，内部验证C-index为0.757。 结论:18F-FDG PET可作为评估CRC微卫星状态、HER2表达的无创工具；MTV 80%与CEA为MSI-H的独立危险因素，TLG 80%和 CV为HER2表达的独立危险因素。

abstractsObjective:To investigate the predictive value of 18F-FDG PET related metabolic parameters on microsatellite instability-high (MSI-H) and human epidermal growth factor receptor-2(HER2) expression in colorectal cancer (CRC). Methods:The 18F-FDG PET imaging, clinical and pathological data of 101 CRC patients (58 males, 43 females; age 68.0(58.0, 75.0) years) admitted to Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2016 to March 2024 were retrospectively collected, including 17 cases in MSI-H group, 84 cases in microsatellite stability/microsatellite instability-low (MSS/MSI-L) group, 23 cases in HER2 expression group, 34 cases in non-HER2 expression group, and 44 patients without HER2 detection. Univariate analyses (independent-sample t test, Mann-Whitney U test, χ2 test) and multivariate logistic regression analysis were used to screen out independent risk factors, and ROC curve was used to evaluate the predictive efficacy. Bootstrap method was used to verify the model internally. Results:There were significant differences in metabolic tumor volume (MTV) 80% between MSI-H group and MSS/MSI-L group (2.1(1.6, 4.0) vs 1.4(1.0, 2.7) cm 3;Z=-2.10, P=0.036), and total lesion glycolysis (TLG) 80% and carcinoembryonic antigen (CEA) were significantly different between those 2 groups ( Z=-2.27, χ2=6.40, both P<0.05). There were significant differences in TLG 80% (29.0(16.1, 41.0) vs 14.3(9.4, 22.9) g; Z=-2.80, P=0.005) between HER2 expression group and non-HER2 expression group, and significant differences were also found in MTV 80%, heterogeneity index (HI) and CV ( Z=-2.24, t values: -2.26, 2.54, all P<0.05). The independent risk factors for MSI-H were MTV 80% (odds ratio ( OR)=1.326, 95% CI: 1.015-1.733, P=0.038) and CEA ( OR=0.200, 95% CI: 0.056-0.706, P=0.012), with the AUC for the combined model of 0.730 (95% CI: 0.605-0.856), and the concordance index (C-index) of 0.716. The independent risk factors for HER2 expression were TLG 80% ( OR=1.037, 95% CI: 1.001-1.073, P=0.041) and CV ( OR=1.467, 95% CI: 1.073-2.005, P=0.016), with the AUC for the combined model of 0.775 (95% CI: 0.645-0.875), and the C-index of 0.757. Conclusions:18F-FDG PET can be used as a noninvasive tool to evaluate CRC microsatellite status and HER2 gene amplification. MTV 80% and CEA are independent risk factors for MSI-H; TLG 80% and CV are independent risk factors for HER2 expression.