直肠癌术前磁共振成像特征与微卫星不稳定状态的相关性

Relationship between preoperative MRI features of rectal cancer and microsatellite instability status

目的探讨利用直肠癌磁共振成像(MRI)参数预测微卫星不稳定(MSI)状态的可行性。方法242例直肠癌患者根据MSI基因检测结果分为微卫星低度不稳定(MSI-L)组230例和微卫星高度不稳定(MSI-H)组12例。比较两组临床特点和术前MRI参数[如表观扩散系数(ADC)、肿瘤最大轴向长度(ATL)、肿瘤最大纵向长度(LTL)、ATL/LTL、切缘(CRM)、淋巴结转移]差异,分析MSI-H相关影响因素。根据患者的临床病理特征和KRAS、BRAF基因,分析直肠癌患者术前MRI参数与MSI-H状态的相关性,评估ATL、ATL/LTL对直肠癌患者MSI-H的诊断价值。结果两组肿瘤大小、分化程度比较差异有统计学意义(P均<0.05)。MSI-H组ATL和ATL/LTL高于MSI-L组,差异有统计学意义(P均<0.05)。两组ADC、LTL及淋巴结转移、CRM情况差异无统计学意义(P均>0.05)。多因素Logistic回归分析显示,ATL和ATL/LTL是直肠癌患者MSI-H的独立危险因素(P均<0.05)。ATL截断值取13.50 mm,其诊断直肠癌患者MSI-H的敏感度为0.750,特异度为0.909;ATL/LTL截断值取0.287,其诊断直肠癌患者MSI-H的敏感度为0.667,特异度为0.909。结论直肠术前MRI参数与患者MSI-H状态相关,检测ATL、ATL/LTL数据对直肠癌患者MSI-H状态具有较高的诊断价值。

Objective To investigate the feasibility of using magnetic resonance imaging(MRI)parameters of rectal cancer to predict microsatellite instability(MSI)status.Methods A total of 242 patients with rectal cancer were divided into the microsatellite low instability(MSI-L)group(n=230)and microsatellite highly instability(MSI-H)group(n=12)according to the MSI test results.We compared the clinical features and preoperative MRI parameters[apparent diffusion coefficient(ADC),maximum axial length of tumor(ATL),maximum longitudinal length of tumor(LTL),ATL/LTL,circumferential margin(CRM),and lymph node metastasis]between the two groups,and analyzed the correlation between preoperative MRI parameters and MSI-H status in rectal cancer patients according to the clinicopathological characteristics of patients and KRAS and BRAF genes,and evaluated the diagnostic value of ATL,ATL/LTL in MSI-H in rectal cancer patients.Results There were significant differences in tumor size and differentiation between the two groups(all P<0.05).ATL and ATL/LTL in the MSI-H group were significantly higher than those in the MSI-L group,with statistically significant difference(both P<0.05).There were no significant differences in ADC,LTL,lymph node metastasis or CRM between the two groups(all P>0.05).Multivariate Logistic regression analysis showed that ATL and ATL/LTL were independent risk factors for MSI-H in rectal cancer patients(both P<0.05).The ATL cut-off value was 13.50 mm,and the sensitivity of MSI-H in rectal cancer patients was 0.750 and the specificity was 0.909;the ATL/LTL cut-off value was 0.287,and the sensitivity of MSI-H in rectal cancer patients was 0.667 and the specificity was 0.909.Conclusion Preoperative MRI parameters are correlated with MSI-H status,and the detection of ATL and ATL/LTL data has high diagnostic value for MSI-H status in rectal cancer patients.