腔内超声对直肠癌术前分期诊断的应用价值

Endoluminal Ultrasonography in the Preoperative Staging of Rectal Carcinoma

目的:评价腔内超声(ELUS)对直肠癌术前分期诊断的准确性及局限性。方法:对58例直肠癌术前行ELUS检查,参考TNM分期标准进行术前分期诊断,并与手术及术后病理结果对照。结果:ELUS对58例直肠癌浸润深度诊断符合率达79.3%,T1、T2、T3、T4各期诊断灵敏度分别为100%、58.8%、87.5%、83.3%。对T2期诊断灵敏度最低,误诊7例中6例过深判断为T3期,且均为溃疡型腺癌。ELUS对54例直肠癌淋巴结转移诊断灵敏度、特异度、准确度分别为76.9%、75.0%、75.9%。淋巴结转移ELUS漏诊6例,淋巴结转移ELUS诊断假阳性7例。结论:ELUS对直肠癌浸润深度及肠周淋巴结转移诊断准确度较高,可成为直肠癌术前分期诊断良好的方法。对T2期的过深判断为影响诊断符合率的重要因素,肿瘤导致肠腔明显狭窄或肿瘤位于直肠上段也影响ELUS的准确性。

Objective: To assess the accuracy and limitations of endoluminal ultrasonography (ELUS) in preoperative staging of rectal cancer. Methods: ELUS was performed preoperatively in 58 patients with rectal carcinoma, in which no preoperative treatment was given. The results of ELUS correlated with operative and pathologic findings according to the TNM classification. Results: The overall accuracy of ELUS in T stage was 79.3%. The sensitivity of ELUS for T1, T2, T3 and T4 carcinoma was 100%, 58.8%, 87.5%, 83.3%, respectively. The sensitivity for T2 carcinoma was the lowest, and overstaging as a T3 carcinoma occurred in 6 of 7 patients being misdiagnosed, which were ulcerative adenocarcinoma. The sensitivity, specificity and accuracy of ELUS in lymph node metastasis were 76.9%, 75.0%, 75.9%, respectively. The diagnosis of ELUS in lymph nodes metastasis was false negative in 6 patients and was false positive in 7 patients. Conclusions: The ELUS should become an important imaging tool in the preoperative assessment of the depth of tumor invasion and lymph node metastasis of rectal carcinoma. The overstaging of T2 carcinoma is an important unfavourable factor in assessing the invasion depth with ELUS, In addition, rectal stenosis caused by carcinoma and tumor locating in the superior segment of rectum also decrease the accuracy of ELUS.