Preoperative staging of rectal cancer: pelvic MRI plus abdomen and pelvic CT. Does extrahepatic abdomen imaging matter? A case for routine thoracic CT

Objective To assess the quality of preoperative magnetic resonance imaging (MRI) staging of rectal cancer, and the clinical significance of abdomen and pelvic computed tomogram (CT) scans in preoperative staging of rectal cancer in a district general hospital. We postulated that the ‘metastatic yield’ of extrahepatic abdominal imaging is poor, and rarely altered management of rectal cancer. Methods This is a retrospective study of preoperative MRI, CT scans and postoperative histology results of patients who had definitive surgery for rectal cancer at the Mid‐Staffordshire General Hospitals NHS Trust over a 36‐month period. Preoperative multiplanar pelvic MRI locoregional staging was compared with eventual histology. The incidence of and significance of abdomen and pelvic CT detected pathology (including metastasis) in the management of rectal cancers was also assessed. Results Preoperative pelvic MRI correctly predicted ‘clear’ Circumferential resection margins, in 28 of 29 patients who had primary surgery. This is comparable with many published studies. Significant CT detected pathology (including metastasis) on preoperative abdomen and pelvic CT scans was uncommon, and did not influence management of any rectal cancer patient in our study. Discussion Given that exclusive CT detected significant pathology caudal to the liver (extrahepatic abdomen) is rare, can full abdomen and pelvic CT scans be justified for preoperative staging of rectal cancers? – especially where chest X rays are employed for lung staging. Preoperative thoracic and upper abdomen CT scan may be a more productive use of resources. Full abdominal scans may be more appropriate for selection of rectal cancer patients with isolated liver metastasis for metastasectomy.     

CT和MRI对直肠癌术前T、N分期价值的Meta分析

目的比较CT和MRI对直肠癌术前T、N分期的价值。方法收集公开发表的对CT与MRI进行术前直肠癌T、N分期价值比较的国内外所有前瞻性和回顾性研究,按照Meta分析的要求对检索到的原始研究的质量进行评估,对符合条件的所有研究结果进行Meta分析,分别计算在T1～T4、N分期上,CT与MRI的灵敏度和特异度并进行比较。结果符合纳入标准的共9篇文章,总样本量347例。对于T分期,CT的灵敏度为0.772,特异度为0.880;MRI的灵敏度为0.910,特异度为0.935。对于N分期,CT的灵敏度为0.636,特异度为0.734;MRI的灵敏度为0.563,特异度为0.849。结论对于T分期,MRI在灵敏度、特异度均优于CT;对于N分期,CT灵敏度优于MRI,MRI特异度优于CT。另外,直肠癌术前放化疗能显著影响CT和MRI术前T分期的灵敏度和特异度,对于N分期,则影响不明显。     

MRI of extraperitoneal rectal carcinoma

Last years technological developments in imaging field have made a substantial contribution to diagnosis and staging of rectal cancer. Endorectal ultrasound and MRI with endorectal coil are very useful in rectal cancer initial staging thanks to their ability to distinguish between the rectal wall layers. Major ultrasound limitations are presence of inflammations, desmoplastic reaction and small field of view which limits evaluation of perirectal invasion. MRI with phased-array coils, instead, allows depiction of mesorectum and to assess the distance between tumor and mesorectal fascia. Unfortunately CT shows low accuracy compared to MRI in local staging because it fails to distinguish the rectal wall layers. The criterion used in assessing nodal involvement remains unfortunately still the dimensional one even if new contrast media based on nano-iron particles look promising in this regard On reassessment after chemo-radiotherapy treatment, MRI proved to be a very accurate tool thanks to its ability to detect tumor downstaging, disappearance of mesorectal fascia infiltration or even to show a complete response. The presence of recurrence can be studied by contrast enhanced perfusion-MRI or with good accuracy using PET which, however, presents major technical limitations at present.     

Preoperative staging of rectal carcinoma

BACKGROUND: The development of treatment modalities for rectal cancer, including local excision, total mesorectal excision and preoperative radiotherapy, has increased the importance of accurate preoperative staging to allow the optimum treatment to be selected. METHODS: A literature review was undertaken of methods of preoperative staging of rectal carcinoma and the evidence for each was evaluated critically. RESULTS: Clinical assessment of rectal carcinoma may give an indication of fixity but is not accurate for staging. Endoanal ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), radioimmunoscintigraphy and positron emission tomography have all been used for staging. The extent of tumour spread through the bowel wall (T stage) is most accurately assessed by endoanal ultrasonography, although this technique is poor at assessing tumour extension into adjacent organs for which both CT and MRI are more accurate. No method accurately determines lymph node involvement, but endoanal ultrasonography is the best available. Liver metastases may be assessed by abdominal ultrasonography, CT, MRI and CT portography (with increasing sensitivity and cost in that order). CONCLUSION: Endoanal ultrasonography is the most effective method of local tumour staging, with the addition of either CT or MRI if adjacent organ involvement is suspected. Abdominal ultrasonography or CT is recommended for routine preoperative assessment of the liver.     

Pre-operative staging of rectal cancer: MRI or ultrasound?

Optimal management of rectal cancer depends on obtaining accurate and detailed staging information at the time of diagnosis. The majority of this comes from radiological staging investigations such as computed tomography (CT), magnetic resonance imaging (MRI) and endoanal ultrasound (EAUS). Whilst there is little debate on the use of CT to assess distant spread of disease, there is still variation in the use of MRI or EAUS in the local staging of rectal cancer. Both techniques have their roles but MRI is better able to visualise the entire rectum and mesorectum as well as accurately identify the circumferential resection (CRM) margin in relation to the tumour edge. Breach of the CRM is one of the most important predictors of local recurrence and knowledge of its relationship to the tumour determines initial management. MRI has additional advantages in being able to identify other poor prognostic factors such as extramural venous invasion (EMVI) and mucin deposition, which further influence oncological treatment. It also provides the surgeon with accurate information on the relationship of the tumour to surrounding structures and the sphincter complex which is important for surgical planning. This review highlights the important determinants of local staging in rectal cancer and presents the evidence to answer the question as to which is a better imaging modality—MRI or EAUS?     

The Potential of Restaging in the Prediction of Pathologic Response After Preoperative Chemoradiotherapy for Rectal Cancer

BACKGROUND: We performed this study to prospectively evaluate the postchemoradiotherapy performance of transrectal ultrasonography (TRUS), pelvic computed tomography (CT) scan and magnetic resonance imaging (MRI), and endoscopic biopsies for predicting the pathologic complete response of rectal cancer patients. METHODS: Four weeks after completion of preoperative chemoradiotherapy, 46 consecutive patients with mid to low rectal cancer were prospectively evaluated by proctoscopy, TRUS, and pelvic CT scan and MRI. On the basis of T and N status, patients were classified as T0 or T1-4 and N-negative or N-positive. For each staging modality used, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. Findings were compared with the pathologic tumor-node-metastasis stage. RESULTS: On histopathologic analysis, 12 patients had pT0 and 34 had pT1-4 lesions; out of 45 assessable patients, 9 were N-positive. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in predicting T status (T0 vs. T >or=1) were 77%, 33%, 74%, 36%, and 64%, respectively, for TRUS; 100%, 0%, 74%, not assessable, and 74% for CT; and 100%, 0%, 77%, not assessable, and 77% for MRI. The corresponding figures in predicting N status (N-negative vs. N-positive) were, respectively, 37%, 67%, 21%, 81%, and 61% for TRUS; 78%, 58%, 32%, 91%, and 62% for CT; and 33%, 74%, 25%, 81%, and 65% for MRI. CONCLUSIONS: Current rectal cancer staging modalities after chemoradiotherapy allow good prediction of node-negative cases, although none of them is able to predict the pathologic complete response on the rectal wall.     

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??CT and MRI in the diagnosis of rectal cancer staging ZHANG Xiao-peng, SUN Ying-shi. Key Laboratory of Carcinogenesis and Translational Research, Department of Radiology, Cancer Hospital & Institute of Peking University, Beijing 100142, China
Correspondin author?? ZHANG Xiao-peng, E-mail??zxp@bjcancer.org
Abstract Rectal cancer is one of the most common causes of death from cancer. Accurate staging is necessary for optimal treatment. Preoperative staging is an essential factor in the multidisciplinary management of rectal cancer now because tumor stage is the strongest predictive factor for recurrence. The tumor node metastasis (TNM) system is used to describe numerically the anatomical extent of cancer. Various diagnostic methods provide accurate staging. Endorectal ultrasound (EUS) and magnetic resonance tomography are suitable for determining tumor T stage. US is better for T1~2 stage tumor especially. Moreover, MRI has some advantages in T and N stage of advanced rectal cancer. Modern multidetector row CT is predestined for detecting distant metastases as it is a widespread, fast, and reproducible method. MRI is highly accurate in predicting the circumferential resection margin. MRI provides accurate assessment of the tumor relative to the circumferential margin, that is, the mesorectal fascia, the anal and pelvic peritoneal fold, which is valuable for determining therapy protocol and therapy outcome.     

Cancer du rectum: bilan préopératoire

Information concerning the depth of tumour infiltration of the rectal wall and lymph nodes, and the presence of distant metastasis is crucial when planning a curative rectal cancer resection. Preoperative staging is used to determine if neoadjuvant therapy is indicated, as well as whether local excision or radical tumour resection will provide optimal surgical outcome. The most common imaging modalities currently used in the preoperative staging of rectal cancer are endorectal ultrasound, CT scan, and MRI.     

Comparison of CT and MRI in the pre-operative staging of rectal adenocarcinoma and prediction of circumferential resection margin involvement by MRI

Objective It has been suggested that MRI may be used as the sole modality of choice in pre‐operative staging in rectal cancers. Knowledge of tumour stage and a threatened Circumferential Resection Margin (CRM) pre‐operatively are essential for planning neo‐adjuvant therapy and as predictors of local recurrence. At present most units utilize CT scanning to assess these parameters. The aim of our study was two fold: firstly to examine the accuracy of preop CT and MRI staging of rectal cancers compared with final histology and secondly to assess the accuracy of MRI in predicting penetration of the mesorectal envelope (ME). Patients and methods All patients with biopsy proven rectal adenocarcinoma underwent thin slice MRI and CT scan pre‐operatively. Forty‐seven patients have been prospectively entered into the study: 24 male (median age 68 years; range 38–91 years). Eleven patients were unsuitable for surgery leaving 36 patients available for study. Results CT correctly staged patients with T1/T2 rectal cancers more often than MRI (77%vs. 43%, P = 0.226). Patients with T1/T2 tumours were overstaged more often by MRI compared with CT (54%vs. 23%, P = 0.226). A greater proportion of patients with T3 tumours were correctly staged by MRI than CT (76%vs. 41%, P = 0.08); and more T3 disease was understaged by CT than MRI (54 vs. 18%, P = 0.032). CT and MRI staged T4 disease equally. In the assessment of mesorectal envelope integrity, MRI had a sensitivity of 80% and a specificity of 84%. The positive predictive value was 44% and the negative predictive value 96%. Conclusions These results suggest significant differences between accurate pre‐operative ‘T’ staging by CT and MRI for rectal cancer. MRI has the potential however, to accurately assess mesorectal envelope invasion. Further analysis is required to assess whether MRI can be used as the sole modality in pre‐operative staging of rectal cancers.     

64排螺旋CT结肠成像评价术前直肠癌分期

目的探讨直肠癌术前行CT结肠成像（CTC）的临床价值。方法对37例确诊为直肠癌的患者行CTC检查,运用多种后处理方法显示病灶,根据改良Dukes分期法进行CT分期,并与术后病理对照。结果 64排螺旋CT检出全部直肠癌,敏感度为100%,Ⅰ期诊断准确率为89.19%,Ⅱ期为78.38%,Ⅲ期为72.97%,Ⅳ期为100%,总准确率为85.14%。结论 CTC检查对直肠癌术前分期有很高的价值,可以为临床提供更为确切的治疗依据。     

A comparison between intrarectal ultrasound and CT scanning in staging of experimental rectal tumors

The purpose of this study was to compare the accuracy of preoperative staging of experimental rectal tumors by digital rectal exam, intrarectal ultrasound (IRUS), and CT scanning with pathologic exam. Rectal tumor masses were induced in 10 mongrel dogs by submucosal injection of 2-3 cc of Freund's complete adjuvant. One week later, the animals underwent digital rectal exam, IRUS, and pelvic CT scans. Pelvic exenteration specimens were submitted for pathologic evaluation. Evaluations and interpretations were done in blinded fashion by independent examiners. The rectal "tumor" was detected in 9 of 10 digital exams, 10 of 10 IRUS exams, and 1 of 10 CT scans. Correct Duke's staging occurred in 70% of digital exams, 90% of IRUS exams, and 10% of CT exams compared to pathological staging. Lymph nodes were detected on pathologic exam in all animals (8.7/animal, range 3-16), on IRUS in all animals (6.4/animal, range 5-13), and in none of the digital or CT examinations. IRUS was significantly more accurate in detecting (P less than 0.0001) and locally staging tumors (P less than 0.0001), and in detecting and localizing lymphadenopathy compared to CT scan. Intrarectal ultrasound is a simple, highly accurate device for assessing depth of wall penetration of rectal tumors and in detecting pararectal lymph nodes and should be considered the preoperative staging procedure of choice for rectal cancer.     

Accuracy of endorectal ultrasonography and computed tomography for restaging rectal cancer after preoperative chemoradiation

BACKGROUND: Preoperative restaging of irradiated rectal cancer is essential for the planning of optimal therapy. The aim of this study was to compare the accuracy of endorectal ultrasonography (ERUS) and CT in restaging rectal cancer after preoperative chemoradiation and to evaluate the factors affecting the accuracy of ERUS. STUDY DESIGN: Eighty-three patients with initial, locally advanced rectal cancer were prospectively evaluated by ERUS (n=60) and CT (n=80) after preoperative chemoradiation and just before surgery. All patients then underwent subsequent surgical resection and complete pathologic staging. RESULTS: In restaging the depth of invasion, the overall accuracy was 38.3% (23 of 60) by ERUS and 46.3% (37 of 80) by CT. Overstaging was more common than understaging with both imaging modalities. Accuracy for restaging lymph node metastasis was 72.6% (37 of 51) by ERUS and 70.4% (50 of 71) by CT. The predictive value of node-negative cases by ERUS was somewhat lower than that of CT (81.1% versus 85.4%, respectively). Complete pathology-proved remission was not correctly predicted in any of the 11 patients by any imaging modalities. Pathologic T and N staging correlated with the staging accuracy of ERUS (p=0.028 and p=0.001, respectively). CONCLUSIONS: ERUS and CT may allow good prediction of node-negative rectal cancers, although they are inaccurate modalities for predicting treatment response on the rectal wall. New methods of interpretation and diagnostic criteria for ERUS and CT are essential for increasing the accuracy of cancer prediction in at-risk patients.     

直肠癌术前分期方法的研究

评估研究直肠癌术前分期方法。方法:对80例直肠癌病人使用术前腔内超声、CT、MRI检查肿瘤病变的深度和直肠指检及术后病理报告在评估病变深度的正确率。结果:直肠腔内超声检查直肠癌浸润深度的正确诊断率为89.3％,对早期直肠癌的正确诊断率为83.3％。CT正确诊断率为86.4％,早期癌的正确诊断率为66.6％。MRI的正确诊断率为90％,早期癌的正确诊断率为83.3％。直肠指检的诊断正确率仅为52.5％。结论:直肠内超声可分辨直肠壁各层的细微结构,可作为直肠癌术前分期的首选诊断方法。     

MRI在直肠癌术前分期中的作用

目的:评估盆腔MRI检查在直肠癌术前分期和治疗决策中的作用。方法:对2009年4月至2010年6月手术治疗的60例直肠癌病例的术前盆腔MRI检查结果与术后组织病理学诊断结果进行比较,分析MRI对直肠癌术前分期的准确率。结果:MRI对直肠癌浸润深度(T分期)的诊断准确率为75%,对T2期肿瘤的诊断准确率为73.1%,对T3期肿瘤的诊断准确率为86.7%;对淋巴结转移的诊断准确率为32.4%。在病理确诊淋巴结转移的16例病人中,MRI检出淋巴结平均数为5.8枚;在淋巴结转移阴性的44例病人中,MRI检出淋巴结平均数为2.4枚;两组淋巴结数有显著差异(P0.05)。结论:术前MRI检查可较准确地判断肿瘤在直肠壁的浸润深度,但对淋巴转移的诊断准确率较低,故MRI可作为直肠癌术前分期的方法,为新辅助治疗提供依据,为术后辅助化疗提供信息。     

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??Significance of inflatable rectal CT in the diagnosis and clinical staging of rectal cancer LI Wei, LIU Ke-sheng??CUI Gen. Department of General Surgery, Jiaonan Economic and Technological Development Zone Hospital,Jiaonan 266400,China Corresponding author: LI Wei?? E-mail: Liwei_750518@163.com Abstract Objective To evaluate the significance of inflatable rectal CT in the diagnosis and clinical staging of rectal cancer??Methods Inflatable rectal CT of 54 cases of rectal cancer confirmed by surgery pathology between May 207 and July 2009 at Jiaonan Economic and Technological Development Zone Hospital were investigated retrospectively. It evaluated the significance of inflatable rectal CT in the diagnosis and clinical staging of rectal cancer??Results Full expansion of the rectum and sigmoid colon, rectum wrapping around the fat density of the structure of the intestinal wall and the relatively high density and very low density contrast mesocaval were showed clearly in patients with the inflatable rectal CT. The overall accuracy rate of rectal cancer TNM staging was 85.2%??46/54??. The accuracy of T, N and M was 90.7%(49/54??, 87.0% (47/54)and 98.1%(53/54) respectively. Conclusion Inflatable rectal CT can show the size, shape, depth of invasion, lymph node metastasis, the relationship with the surrounding organs and distant metastasis clearly. Imaging features of the mesorectum were clear. Inflatable rectal CT had a higher consistency with TNM staging.It was an important method for the preoperative diagnosis and clinical staging of rectal cancer.     

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??The function and the technical standard of endoscopic ultrasonography for evaluating the TN staging of mid-low rectal cancer REN Zhong??ZHONG Yun-shi. Endoscopy Center and Endoscopy Research Institute??Zhongshan Hospital??Fudan University??Shanghai 200032??China
Corresponding author??ZHONG Yun-shi??E-mail??zhongamy2002@126.com
Abstract Recently with the increasement of the incidence of mid-low rectal cancer??the accurate TN staging becomes more important for making the treatment plan. Compared with CT??MRI and other radiological technology??endoscopic ultrasonography (EUS) has the advantages in the respects of staging before operation??follow-up after operation and evaluation of the effects of radiotherapy and chemotherapy.     

Management of distal rectal cancer: results from a national survey

Owing to the complexity of distal rectal cancer its management requires a multidisciplinary approach. The diagnosis and the response after neoadjuvant chemoradiotherapy are not easy to assess and therefore the surgical approach is heterogeneous. The purpose of this survey is to evaluate the experiences of members of the Italian Society of Surgery in diagnosis and treatment strategies for rectal cancer and compare it with international practice. A questionnaire was devised comprising 18 questions with 11 sub-items making a total of 29 questions and submitted online to all the 2,500 members of the SIC starting from July 2010. The survey was completed in June 2011. The overall response rate was 17.8 % (444). The majority of the Italian surgeons’ responses were in line with the international consensus reflecting the complex management of distal rectal cancer. Other opinions, especially those on staging, diverge from the common view of MRI being the gold standard in the assessment of loco-regional diffusion of the disease and on the superiority of FDG PET-CT versus CT for systemic staging. The timing for the re-staging and for surgery following neoadjuvant chemoradiotherapy does not reflect the international opinion. Italian surgeons are also exposed to the common difficulties encountered internationally in the management of distal rectal cancer. Probably, the implementation of an Italian rectal cancer registry and of many national and international multicentre studies may improve the management of rectal cancer in Italy.     

Reprint of: Important imaging considerations in the pre-operative assessment of rectal cancer

The role of imaging has become central in the pre-operative decision-making process for patients with rectal cancer. The detailed information that is available from high-resolution imaging studies not only provides prognostic information but also allows the surgeon to anticipate potential pitfalls during the operation. The greater the amount of detail known about the tumour, the more selective one can be in the use of pre-operative radiotherapy, which can reduce unnecessary morbidity for minimal gain. Magnetic resonance imaging (MRI) is the most useful modality for the local staging of rectal cancer as it provides the most detail on the important prognostic factors that influence treatment. These include height of tumour from the anal verge, tumour depth of penetration, nodal disease, venous invasion, involvement of the circumferential resection margin. However, endoanal ultrasound (EAUS) is particularly good at staging early tumours and aids in identifying those that are suitable for local excision. We review the important considerations in the pre-operative staging of rectal cancer.     

低位直肠癌术前影像学精准分期及意义

低位直肠癌治疗的目标是降低局部复发率和延长生存期，同时尽可能保留括约肌结构和功能。由于肿瘤与周围结构间隙狭窄而导致手术切缘阳性，将增加低位直肠癌病人局部复发率。MRI通过分析低位直肠癌与周围结构的关系，可预测环周切缘是否为阳性。根据MRI检查结果调整手术切面，有助于降低手术切缘病理阳性率和局部复发率；同时，应用MRI判断切缘阴性而采用单纯手术方式，也可避免新辅助放化疗的毒副反应。然而，治疗策略中的手术方式选择并未达成共识，其原因之一是缺乏低位直肠癌手术定义和规范。高分辨率MRI可通过判断低位直肠癌下缘与肛直肠环上缘的纵向位置关系，以及低位直肠癌向肠壁外浸润深度的横向位置关系，协助确定手术方式，精准选择病人进行适宜的手术，增加了保留括约肌结构和功能的机会。在手术不断精细化和局部化的趋势下，通过新辅助治疗或完全新辅助放化疗实现完全临床缓解后采用“等待观察”的非手术策略，有望成为保留器官及其功能的重要治疗方案之一。目前，病人的选择和完全临床缓解的判断尚处于研究中。     

Important imaging considerations in the pre-operative assessment of rectal cancer

The role of imaging has become central in the pre-operative decision-making process for patients with rectal cancer. The detailed information that is available from high-resolution imaging studies not only provides prognostic information but also allows the surgeon to anticipate potential pitfalls during the operation. The greater the amount of detail known about the tumour, the more selective one can be in the use of pre-operative radiotherapy, which can reduce unnecessary morbidity for minimal gain. Magnetic resonance imaging (MRI) is the most useful modality for the local staging of rectal cancer as it provides the most detail on the important prognostic factors that influence treatment. These include height of tumour from the anal verge, tumour depth of penetration, nodal disease, venous invasion, involvement of the circumferential resection margin. However, endoanal ultrasound (EAUS) is particularly good at staging early tumours and aids in identifying those that are suitable for local excision. We review the important considerations in the pre-operative staging of rectal cancer.