Transit endoscopic ultrasound of colorectal cancer using a 12 MHz catheter probe

Novel endoscopic ultrasonography classification for assured vertical resection margin (≥500 μm) in colorectal endoscopic submucosal dissection

BACKGROUND AND AIM

The risk of local recurrence might be low in pT1 colorectal carcinoma with a tumor vertical margin (VM) ≥500 μm. We investigated the relationship between endoscopic ultrasonography (EUS) findings and VM in cases with colorectal endoscopic submucosal dissection (ESD) categorized as Type 2B according to the Japan NBI Expert Team (JNET) classification.

METHODS

We analyzed 179 JNET Type 2B colorectal tumors resected by ESD at Hiroshima University Hospital from January 2010 to May 2021. The distance from the tumor invasive front to the muscle layer on EUS was defined as the tumor-free distance (EUS-TFD) and classified as Type I (EUS-TFD ≥1 mm) and II (<1 mm). We investigated the relationship between EUS-TFD and VM and analyzed the predictive factors for VM ≥500 μm.

RESULTS

EUS-TFD Type I was diagnosed in 133 (74.3%) lesions: VM ≥500 μm (114, 85.7%); VM <500 μm (19, 14.3%); and VM positive (VM1) (0, 0%). Type II was diagnosed in 46 (25.7%) lesions: VM ≥500 μm (14, 30.5%); VM <500 μm (22, 47.8%); and VM1 (10, 21.7%). In the EUS-TFD Type I cases, 84.5% and 87.8% were protruded and superficial types; whereas for Type II cases, these were 38.9% and 25%, respectively. EUS-TFD classification (Type I), scope operability (good), submucosal invasion depth (<2000 μm), histology at the deepest invasive portion (favorable), and degree of fibrosis (F0/F1) were significant predictors of VM ≥500 μm.

CONCLUSIONS

In JNET Type 2B lesions, EUS-TFD classification is a novel diagnostic indicator to predict VM ≥500 μm in ESD preoperatively.

Colon carcinoma staging by endoscopic ultrasonography miniprobes

Background and Objectives:

Due to the increasing use of endoscopic techniques for colon cancer resection, pretreatment locoregional staging may gain critical interest. The use of endoscopic ultrasonography (EUS) miniprobes in this context has been seldom reported. Our aim was to determine the accuracy of EUS miniprobes for colon cancer staging.

Materials and Methods:

Forty patients with colon cancer (2 in the cecum, 9 in the ascending colon, 5 in the transverse colon, 5 in the descending colon, and 19 in the sigmoid colon) were submitted to staging using 12 MHz EUS miniprobes. EUS and the anatomopathological results were compared with regard to the T and N stages. It was assessed if the location, longitudinal extension, or circumferential extension of the tumor had any influence on the accuracy in EUS staging.

Results:

Tumor staging was feasible in 39 (98%) patients except in one case with a stenosing tumor (out of 6). Globally, T stage was accurately determined in 88% of the cases. In the assessment of the presence or absence of lymph node metastasis, miniprobes presented an accuracy of 82% with a sensitivity of 67%. These results were neither affected by the location nor by the longitudinal or circumferential extension of the tumor.

Conclusions:

EUS miniprobes may play an important role in assessing T and N stages in colon cancer and may represent an incentive to the research of new therapeutic areas for this disease.

Management of colorectal T1 carcinoma treated by endoscopic resection

As a result of recent advances in endoscopic therapeutic technology, the number of endoscopic resections carried out in the treatment of early colorectal carcinomas with little risk of lymph node metastasis has increased. There are no reports of lymph node metastasis in intramucosal (Tis) carcinomas, whereas lymph node metastasis occurs in 6.8-17.8% of submucosal (T1) carcinomas. Three clinical guidelines have been published in Japan and the management strategy for early colorectal tumors has been demonstrated. According to the 2014 Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines for the Treatment of Colorectal Cancer, additional surgery should be done in cases of endoscopically resected T1 carcinoma with a histologically diagnosed positive vertical margin. Additional surgery may also be considered when one of the following histological findings is detected: (i) SM invasion depth ≥1000 µm; (ii) histological type por., sig., or muc.; (iii) grade 2-3 tumor budding; and (iv) positive vascular permeation. A resected lesion that is histologically diagnosed as a T1 carcinoma without any of the above-mentioned findings can be followed up without additional surgery. As for the prognosis of endoscopically resected T1 carcinomas, the relapse ratio of approximately 3.4% (44/1312) is relatively low. However, relapse is associated with a poor prognosis, with 72 cancer-related deaths reported out of 134 relapsed cases (54%). A more detailed stratification of the lymph node metastasis risk after endoscopic resection for T1 carcinomas and the prognosis of relapsed cases will be elucidated through prospective studies. Thereafter, the appropriate indications and safe and secure endoscopic resection for T1 carcinomas will be established.

Diagnostic Value of Endorectal Ultrasound in Preoperative Assessment of Lymph Node Involvement in Colorectal Cancer: a Meta-analysis

BACKGROUND

Nodal invasion by colorectal cancer is a critical determinant in estimating patient survival and in choosing appropriate preoperative treatment. The present meta-analysis was designed to evaluate the diagnostic value of endorectal ultrasound (EUS) in preoperative assessment of lymph node involvement in colorectal cancer.

MATERIALS AND METHODS

We systematically searched PubMed, Web of Science, Embase, and China National Knowledge Infrastructure (CNKI) databases for relevant studies published on or before December 10th, 2014. The sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR) and area under the summary receiver operating characteristics curve (AUC) were assessed to estimate the diagnostic value of EUS. Subgroup analysis and meta-regression were performed to explore heterogeneity across studies.

RESULTS

Thirty-three studies covering 3,016 subjects were included. The pooled sensitivity and specificity were 0.69 (95%CI: 0.63-0.75) and 0.77 (95%CI: 0.73-0.82), respectively. The positive and negative likelihood ratios were 3.09 (95%CI: 2.52-3.78) and 0.39 (95%CI: 0.32-0.48), respectively. The DOR was 7.84 (95%CI: 5.56-11.08), and AUC was 0.80 (95%CI: 0.77-0.84).

CONCLUSIONS

This meta-analysis indicated that EUS has moderate diagnostic value in preoperative assessment of lymph node involvement in colorectal cancer. Further refinements in technology and diagnostic criteria are necessary to improve the diagnostic accuracy of EUS.

Diagnostic performance of EUS for evaluating the invasion depth of early colorectal cancers

BACKGROUND

EUS is one technique used to estimate the invasion depth of early colorectal cancer (CRC), but its diagnostic accuracy remains a matter of debate.

OBJECTIVE

To assess the accuracy of EUS for estimating the invasion depth of early CRC.

DESIGN

Retrospective analysis.

SETTING

Tertiary-care academic medical center.

PATIENTS

The invasion depth of early CRC was estimated by EUS from 1989 through 2012.

INTERVENTIONS EUS MAIN OUTCOME MEASUREMENTS

Accuracy of EUS diagnosis, risk factors for misdiagnosis, and characteristics of lesions that were difficult to image.

RESULTS

We estimated the invasion depth of 714 cases of early CRC on EUS. Of the lesions able to be visualized on EUS, the overall diagnostic accuracy of EUS for differentiating between lesions that could be resected endoscopically (Tis and T1a cancers), and those that required colectomy (T1b cancers) was 89%. Submucosal cancer and a macroscopic classification of superficial type were independent risk factors for misdiagnosis. Ninety lesions (13%) were difficult to image. Risk factors for difficulty in imaging were protruding-type morphology and tumor location in the sigmoid colon or from the descending colon to the cecum.

LIMITATIONS

Single center, retrospective. Experienced endoscopists performed EUS.

CONCLUSIONS

Although some lesions that were protruding or located in the proximal colon were difficult to visualize, EUS is considered a useful technique for the diagnosis of invasion depth and the selection of treatment in patients with early CRC.

Mini-probe ultrasonography for the staging of colon cancer: a systematic review and meta-analysis

AIM

With an increasing array of treatment modalities available for colon cancer, it is increasingly important to stage tumours accurately to allocate the appropriate management. This study evaluated the accuracy of mini-probe endoscopic ultrasound (EUS) in assigning clinical stage to colon cancer.

METHOD

An electronic search was performed in January 2013 using the Embase, MEDLINE and Cochrane databases. This was supplemented by a hand search of published abstracts from scientific meetings. Trials evaluating the accuracy of the mini-probe EUS compared with histopathological grade in determining the clinical stage of colon cancer were included in this pooled analysis. The main outcome measures included accuracy, sensitivity and specificity for T and N staging.

RESULTS

Ten studies were identified which compared the mini-probe EUS staging of 642 colon or rectal cancers with the histopathological specimen. The pooled sensitivity and specificity for staging were 0.91 and 0.98 for T1 tumours, 0.78 and 0.94 for T2 tumours, 0.97 and 0.90 for T3/T4 tumours and 0.63 and 0.82 for nodal staging. Eight per cent of T1/T2 tumours were upstaged to T3/T4 tumours and 5% of T3/T4 tumours were downstaged.

CONCLUSION

Mini-probe EUS is highly effective for assigning clinical stage in colon cancer and in identifying patients who may be suitable for nonsurgical treatment including neoadjuvant chemotherapy or endoscopic resection.

Colonoscopic high frequency mini-probe ultrasound is more accurate than conventional computed tomography in the local staging of colonic cancer

AIM

Colonoscopic high frequency mini-probe ultrasound was compared prospectively with CT in the local staging of colonic cancer.

METHOD

Consecutive patients undergoing surgical resection for colonic cancer were recruited. Preoperative 64-slice CT staging with multiplanar reconstruction was compared with colonoscopic high frequency mini-probe ultrasound using 12 MHz and 20 MHz probes. The three methods of staging (CT, 12 MHz ultrasound and 20 MHz ultrasound) were compared with the histological stage of the resected specimen. This was done using weighted kappa coefficients where weights of 0.7-0.8 were given to penalize disagreements of one level in either direction and weights of zero were given to penalize disagreements of more than one level in any direction.

RESULTS

In total, 38 patients with colonic cancer were included. They were located in the sigmoid (n = 20), descending (n = 5), ascending (n = 2) and transverse colon (n = 1) and in the caecum (n = 7) and splenic (n = 2) and hepatic (n = 1) flexure. Histopathological assessment revealed seven pT1, four pT2, 25 pT3 and two pT4 cancers. In relation to the pathology the weighted kappa coefficients were 0.36 (SE = 0.14), 0.81 (SE = 0.16) and 0.81 (SE = 0.17) for CT, ultrasound 12 MHz and ultrasound 20 MHz. Histopathologically 15 (39.5%) patients were lymph node positive. The sensitivity, specificity and kappa coefficient for detection of nodal disease for CT were 80%, 47.8% and 0.25 (SE = 0.14) compared with 80%, 82.5% and 0.62 for 12 MHz ultrasound (SD = 0.14) and 23%, 90.5% and 0.15 (SD = 0.13) for 20 MHz ultrasound.

CONCLUSION

Colonoscopic ultrasound is significantly more accurate than CT for T staging of colonic cancers. With respect to nodal status, 12 MHz ultrasound offers superior accuracy to CT or 20 MHz ultrasound.

Colorectal Carcinoma: Local Tumor Staging and Assessment of Lymph Node Metastasis by High-Resolution MR Imaging in Surgical Specimens

Purpose. To assess the accuracy of high-resolution MR imaging as a means of evaluating mural invasion and lymph node metastasis by colorectal carcinoma in surgical specimens. Materials and Methods. High-resolution T1-weighted and T2-weighted MR images were obtained in 92 surgical specimens containing 96 colorectal carcinomas. Results. T2-weighted MR images clearly depicted the normal colorectal wall as consisting of seven layers. In 90 (94%) of the 96 carcinomas the depth of mural invasion depicted by MR imaging correlated well with the histopathologic stage. Nodal signal intensity on T2-weighted images (93%) and nodal border contour (93%) were more accurate than nodal size (89%) as indicators of lymph node metastasis, and MR imaging provided the highest accuracy (94%-96%) when they were combined. Conclusion. High-resolution MR imaging is a very accurate method for evaluating both mural invasion and lymph node metastasis by colorectal carcinoma in surgical specimens.

The value of high-resolution three-dimensional endorectal ultrasonography in the management of submucosal invasive rectal tumors

PURPOSE

The aims of this prospective study were 1) to evaluate the accuracy of high-resolution three-dimensional endorectal ultrasonography in distinguishing slight from massive submucosal invasion of early rectal tumors, and 2) to determine the technology's role in treatment selection.

METHODS

A total of 142 consecutive patients with clinically possible pT1 rectal cancers underwent three-dimensional endorectal ultrasonography. Slight or massive irregularity of the hyperechoic submucosal layer was considered to characterize uT1-slight or uT1-massive tumors. Treatment was selected on the basis of ultrasonographic findings: endoscopic resection or full-thickness transanal local excision was selected for uT1-slight lesions, and radical resection was selected for uT1-massive tumors. Ultrasonographic staging was compared with histopathologic staging.

RESULTS

One hundred twenty-six patients were included in the final analyses. Three-dimensional endorectal ultrasonography staged 77 lesions as uT0, 25 as uT1-slight, 20 as uT1-massive, and 4 as uT2. Histologically, adenomas were found in 75 patients and tumor invasion was found in 44 lesions (24 pT1-slight, 16 pT1-massive, 4 pT2). The overall kappa for the concordance between ultrasonographic and histopathologic stagings was 0.81 (95% confidence interval, 0.72-0.89). No invasive carcinomas remained undetected. The depth of invasion was correctly determined in 87.2% of both pT1-slight and pT1-massive lesions. Considering the complete series of 126 patients, the accuracy of this modality in selecting appropriate management was 95.2% (kappa, 0.84; 95% confidence interval, 0.71-0.96). Adequate surgery was performed in 87.5% of pT1 tumors.

CONCLUSION

Three-dimensional endorectal ultrasonography is useful for assessing the depth of submucosal invasion in early rectal cancer and for selecting therapeutic options.

Colorectal carcinoma: in vitro evaluation with high-spatial-resolution 3D constructive interference in steady-state MR imaging

PURPOSE

To retrospectively assess the accuracy of high-spatial-resolution three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging in the evaluation of mural invasion of colorectal carcinoma by using prospectively obtained in vitro images, with histopathologic analysis as the reference standard.

MATERIALS AND METHODS

Institutional review board approval was obtained for the prospective and retrospective components of this study, with informed consent for the former and waiver of informed consent for the latter. Surgical specimens were obtained in 92 patients (61 men, 31 women; mean age, 65 years) and contained 96 colorectal carcinomas. Specimens were examined with a 1.5-T MR system and a 4-cm-diameter loop coil. High-spatial-resolution 3D CISS MR images were obtained with 80 x 80-mm field of view, 512 x 512 matrix, and 0.7-mm section thickness, which resulted in a 0.017-mm(3) voxel size. The 3D data sets were postprocessed with surface-rendering software to generate virtual MR endoscopic images. The 3D CISS MR images were compared with histopathologic findings, and virtual MR endoscopic images were compared with macroscopic findings at surgery. Statistical analysis was performed with Spearman rank correlation.

RESULTS

In 92 (96%) colorectal carcinomas, the depth of mural invasion depicted by 3D CISS MR imaging correlated well with the histopathologic stage, although the stage assigned with 3D CISS MR imaging was higher than that assigned with histopathologic analysis in four (4%) carcinomas (r = 0.976, P < .001). Sensitivity, specificity, and accuracy were 100%, 94%-96%, and 98%-100%, respectively. In 91 (95%) carcinomas, virtual MR endoscopy clearly depicted the macroscopic type of carcinoma, including gross configuration and tumor ulceration (r = 0.916, P < .001).

CONCLUSION

High-spatial-resolution 3D CISS MR imaging has high diagnostic accuracy in the in vitro evaluation of mural invasion and macroscopic features of colorectal carcinomas.

Preoperative Staging of Rectal Cancer: Comparison of 3-T High-Field MRI and Endorectal Sonography

OBJECTIVE

The aim of this study was to compare phased-array 3-T MRI and endorectal sonography in the preoperative staging of rectal cancer.

MATERIALS AND METHODS

During an 8-month period, 24 patients with rectal cancer underwent both 3-T MRI performed with phased-array coils and 7.5- to 10-MHz endorectal sonography in the 3 weeks before surgical resection. Three radiologists independently reviewed the MR and endorectal sonographic images. The histopathologic findings in resected specimens were used to evaluate the sensitivities and specificities of these techniques for invasion of the muscularis propria and perirectal tissue and for lymph node involvement. Receiver operating characteristic (ROC) analysis was used to compare the diagnostic accuracies of the techniques.

RESULTS

For muscularis propria invasion, the mean sensitivities of both MRI and endorectal sonography were 100%, and the mean specificities were 66.7% and 61.1%, respectively. The differences in the mean sensitivities and specificities were not statistically significant (p > 0.05 in each case). For perirectal tissue invasion, MRI and endorectal sonography had comparable sensitivities and specificities (91.1% vs 100%, 92.6% vs 81.5%; p > 0.05 in each case). They also had similar sensitivities and specificities for lymph node involvement (63.6% vs 57.6%, 92.3% vs 82.1%; p > 0.05 in each case). ROC curves for muscularis propria invasion and lymph node involvement showed no differences in diagnostic accuracy. The mean area under the ROC curve for endorectal sonography (A(Z) = 0.996) for perirectal tissue invasion, however, showed higher accuracy than that of MRI (A(Z) = 0.938, p = 0.028).

CONCLUSION

The sensitivity, specificity, and accuracy of 3-T MRI were similar to those of endorectal sonography for muscularis propria invasion and lymph node involvement, but for perirectal tissue invasion, 3-T MRI was less accurate than endorectal sonography.

Depiction and Local Staging of Rectal Tumors: Comparison of Transrectal US before and after Water Instillation

PURPOSE

To determine whether transrectal ultrasonography (US) with intrarectal water instillation can improve the depiction and accuracy of US in local staging of rectal tumors.

MATERIALS AND METHODS

Between October 1999 and February 2002, 63 patients (mean age, 56 years; age range, 23-91 years) with 63 rectal tumors were evaluated with transrectal US before and after intrarectal water instillation. Transrectal US examinations were performed with a 7-10-MHz radial transducer. Immediately after the first transrectal US examination, the rectal lumen was filled with 50-150 mL of degassed water, and a second US examination was performed. All patients underwent surgery within 1 month after transrectal US. Depiction of the tumor was compared between the two methods. The McNemar test was used to compare the accuracy between the two techniques in local staging of the tumor by using pathologic findings in the resected specimen as the standard.

RESULTS

The tumors ranged from 0.5 to 8.0 cm (mean, 2.8 cm) as measured at pathologic evaluation. All 63 tumors were clearly depicted at transrectal US after water instillation, while only 42 (67%) of the tumors were depicted at transrectal US before water instillation. In the 42 tumors clearly depicted at transrectal US examinations both before and after water instillation, the accuracy of transrectal US in local tumor staging was significantly higher after water instillation (85.7% [36 of 42]) than before water instillation (57.1% [24 of 42]; P <.001).

CONCLUSION

Water instillation during transrectal US examination of rectal tumors improves the depiction and local staging of the tumors.