Department of Medical-Diagnostic Sciences and Special Therapies, University of Padua, Padua, Italy.
Surgery. 2011 Jan;149(1):56-64. doi: 10.1016/j.surg.2010.03.025. Epub 2010 May 10.
The aim of the study was to assess the accuracy of imaging techniques in predicting pathologic tumor (ypT), node (ypN) stages and the circumferential resection margin (ypCRM) status of rectal cancers after preoperative chemoradiotherapy (CRT).
Using pelvic computed tomography (CT), magnetic resonance imaging (MRI), and endorectal ultrasound (ERUS), 90 consecutive patients with locally advanced mid-to-low rectal cancer were prospectively assessed. Postirradiation T and N stages and infiltration of the CRM, as assessed by CT, MRI and ERUS, were compared with histopathologic findings.
The accuracy of ypT staging was low, whatever the imaging technique used (37% by CT, 34% by MRI, and 27% by ERUS), the most frequent inaccuracy being overstaging. Imaging showed a good specificity and good negative predictive values (NPV) when mural staging was grouped into ypT ≤ 3 and ypT4 categories; in particular, ERUS achieved a 92% specificity and 95% NPV. CRM involvement was correctly predicted in 71% of patients by CT (74% specificity; 93% NPV) and in 85% by MRI (88% specificity; 95% NPV). The accuracy for nodal staging was 62%, 68%, and 65% by CT, MRI and ERUS, respectively; the corresponding NPV were 88%, 78%, and 76%.
Current imaging techniques are inaccurate in restaging rectal cancer after CRT but are useful in predicting T ≤ 3 tumors, cases with negative nodes and tumor-free CRM. These findings may be of clinical relevance for planning less invasive surgery.
本研究旨在评估影像学技术在预测局部中低位直肠癌患者新辅助放化疗（CRT）后肿瘤病理分期（ypT）、淋巴结（ypN）分期和环周切缘（ypCRM）状态的准确性。
对 90 例局部进展期中低位直肠癌患者进行前瞻性评估，使用盆腔计算机断层扫描（CT）、磁共振成像（MRI）和直肠内超声（ERUS）。比较 CT、MRI 和 ERUS 评估的照射后 T 分期和 N 分期以及 CRM 浸润与组织病理学检查结果。
无论使用哪种影像学技术，ypT 分期的准确性均较低（CT 为 37%，MRI 为 34%，ERUS 为 27%），最常见的不准确是过度分期。当将壁层分期分为 ypT≤3 和 ypT4 两类时，影像学检查具有良好的特异性和良好的阴性预测值（NPV）；特别是 ERUS 具有 92%的特异性和 95%的 NPV。CT 正确预测了 71%（74%的特异性；93%的 NPV）患者的 CRM 受累情况，MRI 正确预测了 85%（88%的特异性；95%的 NPV）患者的 CRM 受累情况。CT、MRI 和 ERUS 对淋巴结分期的准确性分别为 62%、68%和 65%，相应的 NPV 分别为 88%、78%和 76%。
目前的影像学技术在 CRT 后对直肠癌进行再分期并不准确，但对于预测 T≤3 肿瘤、无淋巴结转移和肿瘤无切缘的病例具有一定的预测价值。这些发现可能对计划侵袭性较低的手术具有临床意义。
