腔内超声与病理诊断直肠癌浸润深度的对比研究

目的 评价腔内超声（ELUS）对直肠癌浸润深度诊断的准确性,探讨其影响因素。方法 对117例未放化疗的直肠癌患者术前行腔内超声检查,参考TNM分期标准进行浸润深度分期诊断,并与术后病理组织学结果对照;分析肿瘤部位、肿瘤浸润深度、病变周围炎症和纤维化等因素对诊断准确性的影响。结果 腔内超声对117例直肠癌浸润深度诊断总准确性达76、9％（90／117）,pT1、pT2、pT3、pT4各期诊断灵敏性分别为87．5％（7／8）、51、7％（15／29）、85．7％（60／70）、80．0％（8／10）;共误诊27例,其中14例过深判断,13例过浅判断。腔内超声对pT2期诊断灵敏性最低,误诊14例中13例腔内超声过深判断为uT3期;肿瘤浸润深度、炎症或纤维化深度〉1／3肌层的pT2期直肠癌腔内超声易过深判断。过浅判断13例中7例肿瘤位于直肠上段、4例肿瘤导致肠腔明显狭窄。腔内超声对直肠中下段肿瘤浸润深度误诊率为18．5％（17／92）,对于直肠上段肿瘤误诊率达40．0％（10／25）,两组误诊率比较差异有统计学意义（P=0．024）。结论 腔内超声对直肠癌浸润深度诊断总准确性较高,但存在过深判断及过浅判断的可能性,过深判断为影响pT2期直肠癌诊断准确性的重要因素,炎症、纤维化及肿瘤累及深度可能与过深判断有关;肿瘤位于直肠上段或肠腔明显狭窄为过浅判断的常见原因。

The assessment of wall invasion of rectal carcinoma: correlation of endoluminal ultrasonographic and pathologic findings

OBJECTIVE: To evaluate the accuracy of endoluminal ultrasonography (ELUS) in the preoperative assessment of wall invasion of rectal carcinoma and analyze its influencing factors. METHODS: ELUS was performed preoperatively in 117 patients with rectal carcinoma, in which no preoperative treatment was given. The results of ELUS were correlated with operative and pathologic findings according to the TNM classification. We observed the following factors and analyzed their impact on the accuracy of ELUS: tumor location, the depth of the tumor invasion, and the inflammatory cell infiltration and fibrosis peritumor. RESULTS: The overall accuracy of ELUS in T stage was 76.9% (90/117). The sensitivity of ELUS for pT(1), pT(2), pT(3) and pT(4) carcinoma was 87.5% (7/8), 51.7% (15/29), 85.7% (60/70), 80% (8/10), respectively. Misdiagnosis occurred in 27 cases, of which 14 cases were overstaged and 13 cases were understaged. The sensitivity for pT(2) carcinoma was the lowest; 14 cases were misdiagnosed, of them 13 cases were overstaged. Overstaging with ELUS for pT(2) carcinoma occurred mainly in these cases in which inflammatory cell infiltration, fibrosis or tumor involved more than one-third of muscularis propria. 13 cases were understaged, of which tumors in 7 cases were located in superior segment of rectum and 4 cases with obviously rectal stenosis. When tumor was located in middle or lower segment of rectum, misdiagnostic rate was 18.5% (17/92); while tumor was located in superior segment of rectum, misdiagnostic rate was 40% (10/25), and differences were statistically significant between two groups in misdiagnostic rate (P = 0.024). CONCLUSION: Although ELUS in the preoperative assessment of wall invasion of rectal carcinoma is useful, it is difficult to avoid overstaging and understaging of ELUS. The overstaging is an important unfavourable factor in assessing the invasion depth of pT(2) carcinoma with ELUS, and the depth of tumor invasion muscularis propria, and the depth of inflammatory cell infiltration and fibrosis might be responsible for overstaging. Obviously rectal stenosis and tumor being located in the superior segment of rectum might cause understaging.