低位直肠癌磁共振影像学分期的精确评估

发布时间：2018-05-30 23:22

本文选题：磁共振影像 + 低位直肠癌　；参考：《中国实用外科杂志》2017年06期

【摘要】：局部进展期低位直肠癌的主要治疗策略仍为根治性手术。由于解剖结构特殊,低位直肠癌经根治性手术后病理学环周切缘(pathological circumferential resection margin,pCRM)阳性率明显高于中上段直肠癌。术前准确分析直肠癌与直肠肛管肌层、括约肌复合体、肛提肌以及周围器官的相互关系,有助于合理选择手术切面并降低pCRM阳性率。高分辨率磁共振影像(MRI)则已经被应用于判断与pCRM相关的危险因素,包括直肠癌侵犯至内括约肌全层及以上,直肠癌与直肠系膜筋膜或肛提肌间距离1mm,直肠癌下缘与肛缘距离4 cm,直肠癌位于前1/4象限,以及直肠壁外血管侵犯等。如果存在上述危险因素建议行扩大的腹会阴联合切除术以避免pCRM阳性的发生。低位直肠癌经根治性手术治疗即意味着器官丢失,对于保肛意愿强烈的病人导致生活质量下降。目前,新辅助放化疗局部控制能力显著提高,直肠癌原发灶明显退缩,甚至可以达到病理学完全缓解。特别是对于低位直肠癌,经新辅助放化疗并获得临床完全缓解(cCR),则存在实施非手术治疗的可能。在判断临床完全缓解时,影像学检查特别是MRI发挥着重要的作用。应用MRI判断肿瘤体积变化值,肿瘤再分期,MRI肿瘤退缩分级等被应用于判断cCR。未来的研究将结合形态学及功能学共同应用于直肠癌新辅助放化疗效果的评价中。
[Abstract]:Radical surgery is still the main treatment strategy for local advanced low rectal cancer. Because of the special anatomical structure, the positive rate of pathological circumferential resection marginal pCRM was significantly higher in low rectal cancer than that in middle and upper rectal cancer after radical operation. Preoperative analysis of the relationship between rectal cancer and rectum anal muscle layer, sphincter complex, levator ani muscle and surrounding organs was helpful to select the surgical section and reduce the positive rate of pCRM. High-resolution magnetic resonance imaging (MRI) has been used to identify risk factors associated with pCRM, including the involvement of rectal cancer throughout the internal sphincter layer and above. The distance between rectal cancer and rectum mesenteric fascia or levator ani muscle was 1 mm, the distance between rectal cancer lower margin and anal margin was 4 cm, rectal cancer was located in the first 1 / 4 quadrant, and the invasion of extramural rectum vessels. If these risk factors exist, extended abdominal perineum resection is recommended to avoid pCRM positive. Radical surgical treatment of low rectal cancer means organ loss, which leads to a decline in quality of life for patients with strong anal-preserving intentions. At present, the local control ability of neoadjuvant radiotherapy and chemotherapy has been improved significantly, the primary tumor of rectal cancer has retreated obviously, and even the complete remission of pathology can be achieved. Especially for low rectal cancer, it is possible to carry out non-operative treatment after neoadjuvant radiotherapy and chemotherapy and complete clinical remission. Imaging, especially MRI, plays an important role in judging clinical complete remission. MRI was used to judge the volume of tumor and tumor retraction grade was used to determine the tumor size. Future studies will be combined with morphology and functional evaluation of neoadjuvant radiotherapy and chemotherapy for rectal cancer.
【作者单位】：北京大学人民医院放射科;
【分类号】：R445.2;R735.37

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