Recently, treatment strategy of rectal cancer has undergone a dramatic change. Application of total mesorectal excision and preoperative chemoradiation therapy (PCRT) has become standard procedure for locoregional and locally advanced rectal cancer, respectively. Functional and morphological radiologic evaluation as well as multidisciplinary approach is both essential for planning patient-specific therapy. In other words, the needs for more accurate T-and N-staging and assessment of circumferential resection margin, both before and after PCRT, are increasing rapidly. Although there is no consensus on the role of diagnostic imaging such as endorectal ultrasonography, computed tomography and magnetic resonance imaging (MRI), in evaluation of rectal cancer patient so far, MRI is emerging as an essential imaging modality with superior trssue contrast and multiplanar approach.
Colorectal Neoplasms ; Consensus ; Diagnostic Imaging ; Humans ; Magnetic Resonance Imaging ; Rectal Neoplasms

Neoadjuvant chemoradiotherapy (NCRT) combined with total mesorectal excision (TME) has become the recommended standard treatment strategy for local advanced rectal cancer (cT3 or cN+). After neoadjuvant chemoradiotherapy, preoperative T/N re-staging and efficacy evaluation of rectal cancer are directly related to the available treatment options and prognosis, so they are the common questions concerned by physicians. At present, magnetic resonance imaging (MRI) is acknowledged to be one of the more effective and feasible methods of T/N re-staging and efficacy evaluation, especially in the molecular microscopic scale. The diffusion weighted imaging (DWI) can reflect the movement of water molecules outside the tumor cells, and the multi-phase dynamic contrast enhanced MRI (DCE-MRI) can indirectly reflect the permeability of tumor vascular wall and local blood perfusion of tumor from the view of pathophysiological point. Because of the influence of edema, inflammatory response and fibrous tissue proliferation after radiotherapy, scholars both at home and abroad increasingly pay more attentions to the accuracy of T/N re-staging and efficacy prediction in MRI following neoadjuvant therapy. In this review, we elucidate the application value and limitation of MRI based on T/N re-staging and local efficacy evaluation.
Chemoradiotherapy ; Humans ; Magnetic Resonance Imaging ; Neoadjuvant Therapy ; Neoplasm Staging ; Rectal Neoplasms ; diagnostic imaging ; therapy ; Treatment Outcome

Objective: To explore the application value of diffusion kurtosis imaging (DKI) in the differential diagnosis of rectal tumors and evaluating the prognostic factors associated with rectal adenocarcinoma. Methods: A total of 105 patients with rectal tumors admitted in the First Affiliated Hospital of Zhengzhou University from December 2018 to August 2020 were retrospectively analyzed. All patients underwent high-resolution magnetic resonance DKI scanning. The mean diffusivity (MD), mean kurtosis (MK) and apparent diffusion coefficient (ADC) were measured and the relationship of these parameters with pathological types and prognostic factors of rectal tumor were analyzed. The diagnostic efficacy of MD, MK, and ADC for positive circumferential resection margin (CRM) and extramural venous invasion (EMVI) of rectal adenocarcinoma was evaluated by the receiver operating characteristic (ROC) curve. Results: MD and ADC were only related to pathological type. The MD and ADC were (2.091±0.390)×10(-3) and (1.478±0.265)×10(-3) mm(2)/s in mucinous adenocarcinoma, higher than (1.136±0.182)×10(-3) and (0.767±0.077)×10(-3) mm(2)/s in unspecified adenocarcinoma and (1.617±0.697)×10(-3) and (0.940±0.179)×10(-3) mm(2)/s in tubulo-villous adenoma. The MD and ADC in unspecified adenocarcinoma were lower than those in tubule-villous adenoma (P<0.05). Nevertheless, MK was associated with pathological type, N stage, CRM and EMVI. The MK was 0.566±0.110 in mucinous adenocarcinoma, lower than 0.982±0.135 in unspecified adenocarcinoma and 0.827±0.121 in tubulo-villous adenoma. The MK in unspecified adenocarcinoma was higher than that in intubulo-villous adenoma. The MK was 0.984±0.107 in pN1-2, higher than 0.881±0.146 in pN0. The MK was 0.990±0.142 in positive CRM, higher than 0.862±0.114 in negative CRM. The MK was 0.996±0.140 in positive EMVI, higher than 0.832±0.100 in negative EMVI (P<0.05). The ROC curves showed that the AUCs of MD, MK and ADC in diagnosing positive CRM were 0.459, 0.653 and 0.408, respectively; with MK=1.006 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 51.9% and 81.0%, respectively. The AUCs of MD, MK and ADC values in diagnosing positive EMVI were 0.510, 0.662 and 0.388, respectively; with MK=1.010 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 50.9% and 87.5%, respectively. Conclusions: DKI quantitative parameter is helpful for discriminating rectal tubulo-villous adenoma, unspecified adenocarcinoma, and mucinous adenocarcinoma, and is helpful for predicting the prognosis of patients with rectal adenocarcinoma. High MK is associated with positive CRM and EMVI.
Humans ; Adenocarcinoma/diagnostic imaging* ; Adenocarcinoma, Mucinous/diagnostic imaging* ; Adenoma, Villous/diagnostic imaging* ; Diffusion Magnetic Resonance Imaging/methods* ; Prognosis ; Rectal Neoplasms/pathology* ; Retrospective Studies ; Sensitivity and Specificity

OBJECTIVETo evaluate the accuracy of transrectal ultrasonography (TRUS) in the assessment of the invasion depth of rectal cancer, and analyze the value of TRUS in diagnosis of early rectal cancer.

METHODSTRUS was performed preoperatively in 163 patients with rectal cancer, and the results was compared with the postoperative pathological findings according to TNM staging. The early rectal cancer was diagnosed if the lesion was limited to mucosa and submucosa. The tumor located in mucosa was defined as mucosal cancer, while as submucosal cancer when the tumor invading into submucosa. Sixteen cases were confirmed as early cancer by pathology after the operation. No patients received chemotherapy and radiotherapy before operation.

RESULTSThe sensitivity of TRUS in the staging of the early rectal cancer was 87.5% (14/16), specificity was 98.6% (145/147), and the positive predictive value was 87.5% (14/16). The sensitivity of TRUS in predicting mucosal and submucosal cancer was 85.7% (6/7) and 66.7% (6/9), respectively. Sixteen patients with early rectal cancer were examined before and after filling rectum with water. After filling rectum, all tumors were visualized clearly, while 14 tumors were correctly diagnosed as early rectal cancer. Before filling rectum, only 6 tumors were visualized clearly, and 3 tumors were staged correctly. The ultrasonographic appearance of early rectal cancer manifested in two kinds: protruded and ulcerative, and most were protruded (81.6%).

CONCLUSIONSTRUS is a valuable imaging examination for diagnosis of early rectal cancer preoperatively. Visualization rate and diagnostic accuracy of early rectal cancer are improved dramatically after filling rectum with water.

Adult ; Aged ; Aged, 80 and over ; Early Diagnosis ; Endosonography ; Female ; Humans ; Male ; Middle Aged ; Neoplasm Invasiveness ; diagnostic imaging ; Rectal Neoplasms ; diagnostic imaging ; pathology ; Rectum ; diagnostic imaging ; Sensitivity and Specificity

Rectal cancer is one of the most common malignancies in human. Because rectal cancer locates in the narrow pelvis and is close to many complicated anatomic structures, seeking R0 resection and decreasing the positive rate of circumferential resection margin become the focus of concern for surgeons. The authors review the diagnosis standard of rectal cancer in AJCC TNM cancer staging (seventh edition) and guideline of College of American Pathologists, and propose the concept of "diagnosis priority using the standardized methods". Selecting the correct medical imaging and pathology diagnosis methods is the key to improve the standardized and individualized comprehensive therapy.
Diagnostic Imaging ; methods ; standards ; Humans ; Neoplasm Staging ; Prognosis ; Rectal Neoplasms ; diagnosis ; pathology

OBJECTIVETo assess the effect of preoperative long course radiotherapy (RT) on anastomotic leakage (AL) after low anterior resection(LAR) for rectal cancer.

METHODSMedline, EMBASE, China National Knowledge Infrastructure,the Cochrane Library databases and other databases were searched for relevant studies. Correlation between preoperative long course RT and AL after LAR for rectal cancer was examined. Review Manager 5.2 software was used to pool raw data and test the heterogeneity of existing studies and to calculate the incorporated odds ratio (OR) and 95% confidence interval (95%CI). Finally, forest plots and funnel plots were created to allow for visual comparison of the results or the effect of publication bias.

RESULTSA total of 881 studies were identified and 10 studies (n=7829) were eligible for the meta-analysis, including 2581 cases of preoperative RT, and 5248 cases of surgery alone without RT. There was no significant difference in anastomotic leakage rate between the two groups (OR:1.17, 95%CI:0.98-1.39, P=0.09).

CONCLUSIONSPreoperative long course RT did not increase the risk of postoperative AL after LAR in patients with rectal cancer.

Anastomotic Leak ; etiology ; Humans ; Postoperative Complications ; etiology ; Preoperative Care ; Radiography ; Rectal Neoplasms ; diagnostic imaging ; surgery

OBJECTIVETo evaluate the accuracy of 3.0T high-resolution magnetic resonance imaging(MRI) in definition of tumor invasion depth staging (T staging) before operation.

METHODSClinical and radiographic data of 49 rectal cancer patients who underwent radical resection within two weeks after 3.0 T high-resolution MRI examination without preoperative neoadjuvant chemotherapy in Peking University People's Hospital between February 2015 and November 2015 were retrospectively collected. Two radiologists reviewed the MRI imagines and evaluated the location and T staging of rectal cancer independently(radiologist A and B). The kappa statistics was used to evaluate the interobserver agreement, and kappa value greater than 0.81 indicated excellent agreement. The accuracy, sensitivity and specificity of high-resolution MRI in definition of rectal cancer T staging were assessed with pathological result as golden standard.

RESULTSAccording to pathological result of 49 rectal cancer patients, 3 were pT1, 17 were pT2, 22 were pT3, and 7 were pT4a. In 2 cases of mucinous adenocarcinoma, MRI T2WI showed focal or diffuse significantly higher signal close to perirectal fat. And in other 47 patients of non-mucinous adenocarcinoma, MRI T2WI showed equal or higher signal compared with pelvic muscle. Interobserver agreement was excellent in diagnosis of T staging of rectal cancer with 3.0T high-resolution MRI(Kappa=0.87). The accuracy, sensitivity and specificity of both radiologists for T1 staging was 95.9%(47/49), 1/3 and 100%(46/46) respectively, besides, 1 case was both diagnosed correctly and 2 cases were overstaged. For 2 radiologists, the accuracy of T2 staging was 87.8%(43/49) and 91.8%(45/49) respectively, the sensitivity was both 88.2%(15/17), and the specificity was 87.5%(28/32) and 93.5%(30/32) respectively, besides, 15 cases were both diagnosed correctly and 2 cases were overstaged. The accuracy for T3 staging was 89.8%(44/49) and 93.9%(46/49) respectively, the sensitivity was 86.4%(19/22) and 95.5%(21/22) respectively, and the specificity was both 92.6%(25/27). Radiologist A made correct diagnosis for 19 cases, understaged 2 cases and overstaged 1 case. Radiologist B made correct diagnosis for 21 cases and only overstaged 1 case. The accuracy, sensitivity and specificity of both radiologists for T4a staging was 98.0%(48/49), 7/7 and 97.6%(41/42) respectively, besides, 7 cases were both diagnosed correctly. The overall accuracy of T staging was 85.7%(42/49) and 89.8%(44/49) by two radiologists respectively. The accuracy for differentiating T1/T2 from T3/T4 was 91.8%(45/49) and 95.9%(47/49) by two radiologists respectively. Radiologist A overstaged 2 cases and understaged 2 cases, and radiologist B overstaged 2 cases.

CONCLUSIONHigh-resolution MRI can accurately evaluate preoperative T staging of rectal cancer and help select the high-risk rectal cancer patients with over T3 to receive neoadjuvant treatment.

Humans ; Magnetic Resonance Imaging ; Neoadjuvant Therapy ; Neoplasm Staging ; Rectal Neoplasms ; diagnostic imaging ; pathology ; Retrospective Studies ; Sensitivity and Specificity

At present, preoperative assessment of rectal cancer stage mainly relies on imaging examination, and the results of imaging reading will directly determine the treatment. In order to alleviate the reading pressure of the radiologist and improve the efficiency and accuracy of imaging diagnosis, there are related studies on using artificial intelligence automatic recognition system to assist the imaging assessment of rectal cancer staging now. Colorectal Surgery Group, Chinese Society of Surgery of the Chinese Medical Association, along with Beihang University, proposed the expert's advice on the surgical clinical application of rectal cancer staging recognition system based on artificial intelligence platform, so as to guide the standard application of this technology and promote the automation and intelligence of imaging reading.
Artificial Intelligence ; Diagnostic Imaging ; Digestive System Surgical Procedures ; Humans ; Magnetic Resonance Imaging ; Neoplasm Staging ; Rectal Neoplasms/surgery*

OBJECTIVETo evaluate the diagnostic value of 3.0T high-resolution MRI in mesorectal lymph node metastasis of rectal cancer.

METHODSThe images and postoperative pathological data of patients with pathologically diagnosed rectal cancer who underwent prospective 3.0T two dimensional high-resolution MRI rectal examinations and surgery within two weeks after MRI examination at the First Affiliated Hospital, Sun Yat-sen University from November 2015 to November 2016 were retrospectively collected. Patients who received preoperative neoadjuvant therapy and those who did not undergo operation after MRI examination were excluded. The MRI sequences included high-resolution sagittal, coronal and oblique axial T2 weighted image (T2WI) (repetition time/echo time, 3000-4000 ms/77-87 ms; slice thickness/gap, 3 mm/0 mm; field of view, 18-22 cm). Two abdominal MRI radiologists independently assessed the morphology, margin, signal of all visible mesorectal nodes, measured their minor axes (three times for each radiologist) and gave estimation of the malignancy. The criteria of metastatic nodes on high-resolution MRI T2WI were nodes with irregular shape, ill-defined border and/or heterogeneous signal. The results of MRI diagnosis were compared with postoperative pathology. The sensitivity, specificity, accuracy, positive predictive value(PPV) and negative predictive value(NPV) of mesorectal nodes and nodes with different short-axis diameter ranges were calculated to evaluate the diagnostic efficiency of high-resolution MRI. Kappa statistics was used to evaluate the agreement for per node and for per patient between high-resolution MRI and pathological results. A Kappa value of 0-0.20 indicated poor agreement; 0.21-0.40 fair agreement; 0.41-0.60 moderate agreement; 0.61-0.80 good agreement; and 0.81-1.00 excellent agreement.

RESULTSA total of 81 patients were enrolled in the retrospective cohort study, including 50 males and 31 females with age of (59.3±11.1) years. Histopathology showed 1 case of well differentiated adenocarcinoma, 63 of moderately differentiated adenocarcinoma, 9 of moderately to poorly differentiated adenocarcinoma, 2 of poorly differentiated adenocarcinoma, 3 of mucinous adenocarcinoma and 3 of tubulovillous adenocarcinoma. Histopathological staging showed 2 cases in T1 stage, 20 in T2 stage, 45 in T3 stage and 14 in T4 stage; 34 in N0 stage, 40 in N1 stage and 7 in N2 stage; 76 in M0 stage and 5 in M1 stage. A total of 377 nodes were included in the node-by-node evaluation, of which 168 (44.6%) nodes were metastatic from 58.0% (47/81) patients. The median short-axis diameter was 5.4(2.4-18.6) mm in metastatic nodes, which was significantly larger than 3.8 (2.0-8.7) mm in non-metastatic nodes[Z=10.586, P=0.000]. The sensitivity, specificity, accuracy, PPV and NPV were 74.4% (125/168), 94.7% (198/209), 85.7% (323/377), 91.9% (125/136) and 82.2% (198/241), respectively. The Kappa values between high-resolution MRI and histopathological diagnosis for node-by-node and patient-by-patient were 0.71 and 0.70 respectively, indicating good agreements. Fourteen nodes >10 mm were all metastatic. The results of high-resolution MRI for nodal status were consistent with the results of histopathological diagnosis, and the sensitivity, accuracy and PPV were all 100.0%. Among 124 nodes with short-axis diameter of 5-10 mm, 95 (76.6%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 78.9% (75/95), 86.2% (25/29), 80.6% (100/124), 94.9% (75/79) and 55.6% (25/45), respectively. The agreement was fair (Kappa value 0.55) between high-resolution MRI and histopathological diagnosis. Among 239 nodes with short-axis diameter ≤5 mm, 59(24.7%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 61.0% (36/59), 96.1%(173/180), 87.4%(209/239), 83.7%(36/43) and 88.3%(173/196), respectively. The agreement was good (Kappa value 0.63) between high-resolution MRI and histopathological diagnosis.

CONCLUSIONRectal high-resolution MRI has good diagnostic value for estimating metastatic mesorectal nodes by evaluating the morphology, margin and signal of nodes.

Aged ; Female ; Humans ; Lymph Nodes ; Lymphatic Metastasis ; diagnostic imaging ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neoplasm Staging ; Prospective Studies ; Rectal Neoplasms ; diagnostic imaging ; pathology ; Retrospective Studies ; Sensitivity and Specificity

OBJECTIVETo evaluate the value of spiral computed tomography in the preoperative assessment of the degree of tumor infiltration in mesorectum and circumferential resection margin status of rectal cancer compared with large tissue slice technique.

METHODSFifty-seven patients with rectal cancer diagnosed by fiber colonoscopy and pathology from March 2007 to December 2007 underwent preoperative 64-layers spiral CT examination. The degree of tumor infiltration in mesorectum and circumferential resection margin status were evaluated. Large tissue slice technique was applied in the pathologic study after the total mesorectal excision of the rectum to determine the degree of tumor infiltration in mesorectum and the circumferential resection margin status. The spiral CT findings were compared with pathologic results. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the CT results were assessed respectively.

RESULTSThe overall spiral CT accuracy was 93.0% (53/57) for the degree of tumor infiltration in mesorectum, and it was 94.7%, 94.7% and 96.5% for degree I, II, III infiltration, respectively. Fifty-three cases (93.0%) were accurately predicated with the circumferential resection margin status. The sensitivity, specificity, PPV and NPV of spiral CT measurement was 80.0%, 97.6%, 92.3% and 93.2%, respectively, and was consistent well with the histopathological diagnosis.

CONCLUSIONSSpiral CT provides accurate preoperative assessment for the degree of tumor infiltration in mesorectum and circumferential resection margin status of rectal cancer.

Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Male ; Mesentery ; diagnostic imaging ; pathology ; Middle Aged ; Neoplasm Invasiveness ; diagnostic imaging ; Neoplasm Staging ; Predictive Value of Tests ; Rectal Neoplasms ; diagnostic imaging ; pathology ; Rectum ; diagnostic imaging ; pathology ; Sensitivity and Specificity ; Tomography, Spiral Computed