T1~2期直肠癌淋巴结转移的MRI相关因素分析

MRI associated biomarker analysis for diagnosis of lymph node metastasis in T1-2 stage rectal cancer

目的探讨与直肠癌淋巴结转移密切相关的MRI指标,提高通过MRI进行T1~2期直肠癌治疗前淋巴结分期的准确性。方法2015年1月至2019年11月中国医学科学院肿瘤医院经手术病理证实为T1~2期直肠癌的患者327例,术前均行MRI检查。根据病理诊断结果,淋巴结转移组(N+组)57例,非淋巴结转移组(N-组)270例。由两位影像科医师阅片,收集影像学资料。就直肠癌淋巴结转移与临床和MRI特征的关系进行单因素分析和Logistic多因素回归分析。应用受试者工作特征(ROC)曲线分析评价回归模型的诊断效果。结果327例患者中,MR-N评价阳性67例,与病理诊断结果差异有统计学意义(P<0.001)。MRI评价淋巴结转移的灵敏度为45.6%,特异度为84.8%,准确率为78.0%。多因素回归分析显示,肿瘤形态(P=0.002)、肿瘤是否含黏液成分(P<0.001)和MR-N评价(P<0.001)是T1~2期直肠癌淋巴结转移的独立影响因素。ROC曲线分析显示,应用该回归模型评估直肠癌淋巴结转移的曲线下面积为0.786(95%CI:0.720~0.852)。结论联合应用肿瘤形态、肿瘤是否含黏液成分及MR-N评价3项指标可以提高T1~2期直肠癌淋巴结转移评估的准确性。

Objective To explore the diagnostic accuracy improved by magnetic resonance imaging(MRI)biomarkers for lymph node metastasis in T1-2 stage rectal cancer before treatment.Methods Medical records of 327 patients with T1-2 rectal cancer who underwent pretreatment MRI and rectal tumor resection between January 2015 and November 2019 were retrospectively analyzed.Fifty-seven cases were divided into the lymph node metastasis group(N+group)while other 270 cases in the non-lymph node metastasis group(N-group)according to the pathologic diagnosis.Two radiologist evaluated the tumor characteristics of MRI images.The relationship of the clinical and imaging characteristics of lymph node metastasis was assessed by using univariate analysis and multivariable logistic regression analysis.Receiver operating characteristic(ROC)curve was used to evaluate the diagnostic abilities for the differentiation of N-from N+tumors.Results Among the 327 patients,MR-N evaluation was positive in 67 cases,which was statistically different from the pathological diagnosis(P<0.001).The sensitivity,specificity and accuracy of MRI for lymph node metastasis were 45.6%,84.8%and 78.0%,respectively.Multivariate regression analysis showed that tumor morphology(P=0.002),including mucus or not(P<0.001),and MR-N evaluation(P<0.001)were independent influencing factors for stage T1-2 rectal cancer with lymph node metastasis.The area under the ROC curve of rectal cancer with lymph node metastasis analyzed by the logistic regression model was 0.786(95%CI:0.720~0.852).Conclusions Tumor morphology,including mucus or not,and MR-N evaluation can serve as independent biomarkers for differentiation of N-and N+tumors.The model combined with these biomarkers facilitates to improve the diagnostic accuracy of lymph node metastasis in T1-2 rectal cancers by using MRI.