Evaluation of new subclassification of type V(I) pit pattern for determining the depth and type of invasion of colorectal neoplasm

Depth diagnosis of early colorectal cancer: Magnifying chromoendoscopy or image enhanced endoscopy with magnification?

Depth diagnosis is extremely crucial in making a treatment choice between endoscopic resection and surgery in the early stages of cancers. Among several imaging modalities, we use magnifying endoscopy to diagnose lesions by close observation of the findings at mucosal surface layer. In combination with topical staining, magnifying endoscopy enables us to assess the definite pit structure, which referred to as magnifying chromoendoscopy (MCE). The pit pattern classification by MCE was proposed and is now widely accepted as the standard diagnostic criteria for colorectal lesions. Meanwhile, image enhanced endoscopy (IEE) represented by narrow-band imaging was developed to improve the visibility of surface and vascular findings without dyeing. Recent collaborative work performed by endoscopic experts in Japan yielded the unified diagnostic criteria, the Japan NBI Expert Team (JNET) classification, based on the findings of IEE with magnification. In this review, focusing on MCE and IEE with magnification, we aimed to give an outline of the pit pattern classification and the JNET classification, and further discuss their accuracy rate of depth diagnosis of early colorectal lesions by performing a review of the related literature. Both modalities have a high accuracy rate of nearly 90% for depth diagnosis. IEE with magnification is an ideal modality because it helps observe lesions without dye spraying; however, lesions with JNET type 2B have an inadequate diagnostic ability, which should be complemented by MCE. We conclude that accurate diagnosis is possible by examining lesions using both modalities properly to overcome the limitations of each modality.

Role of Magnification Chromoendoscopy in the Management of Colorectal Neoplastic Lesions Suspicious for Submucosal Invasion

BACKGROUND

Correctly predicting the depth of tumor invasion in the colorectal wall is crucial for successful endoscopic resection of superficial colorectal neoplasms.

OBJECTIVE

The aim of this study was to assess the accuracy of magnifying chromoendoscopy in a Western medical center to predict the depth of invasion by the pit pattern classification in patients with colorectal neoplasms with a high risk of submucosal invasion.

DESIGN

This single-center retrospective study, from a prospectively collected database, was conducted between April 2009 and June 2015.

SETTINGS

The study was conducted at a single academic center.

PATIENTS

Consecutive patients with colorectal neoplasms with high risk of submucosal invasion were included. These tumors were defined by large (≥20 mm) sessile polyps (nonpedunculated), laterally spreading tumors, or depressed lesions of any size.

INTERVENTIONS

Patients underwent magnifying chromoendoscopy and were classified according to the Kudo pit pattern. The therapeutic decision, endoscopic or surgery, was defined by the magnification assessment.

MAIN OUTCOME MEASURES

Sensitivity, specificity, and positive and negative predictive values of magnifying chromoendoscopy for assessment of these lesions were determined.

RESULTS

A total of 123 lesions were included, with a mean size of 54.0 ± 37.1 mm. Preoperative magnifying chromoendoscopy with pit pattern classification had 73.3% sensitivity, 100% specificity, 100% positive predictive value, 96.4% negative predictive value, and 96.7% accuracy to predict depth of invasion and consequently to guide the appropriate treatment. Thirty-three rectal lesions were also examined by MRI, and 31 were diagnosed as T2 lesions. Twenty two (70.1%) of these lesions were diagnosed as noninvasive by magnifying colonoscopy, were treated by endoscopic resection, and met the curative criteria.

LIMITATIONS

This was a single-center retrospective study with a single expert endoscopist experience.

CONCLUSIONS

Magnifying chromoendoscopy is highly accurate for assessing colorectal neoplasms suspicious for submucosal invasion and can help to select the most appropriate treatment. See Video Abstract at http://links.lww.com/DCR/A920.

Validity of conventional endoscopy using "non-extension sign" for optical diagnosis of colorectal deep submucosal invasive cancer

BACKGROUND AND STUDY AIMS

 The non-extension sign relates to a localized increase in thickness and rigidity due to deep submucosal invasive (SM-d: depth of 1000 μm or more) cancer. The present study aimed to evaluate the efficacy of the non-extension sign in assessing the optical diagnosis of colorectal SM-d cancer.

PATIENTS AND METHODS

 We retrospectively analyzed 309 patients with 315 early colorectal cancers that had been endoscopically or surgically resected. The non-extension sign was judged from chromoendoscopy (CE) using conventional white-light imaging with indigo carmine, and is taken to be positive when any one of the findings of rigidity of a circular arc, trapezoid elevation, or converging mucosal folds are seen. We assessed comparing the accuracy of CE, magnifying chromoendoscopy (M-CE), and magnifying narrow-band imaging (M-NBI) for the optical diagnosis of colorectal SM-d cancer.

RESULTS

Sensitivity, specificity, and accuracy for the diagnosis of SM-d cancer were 66.0 %, 95.8 %, and 86.3 % for CE; 80 %, 90.7 %, and 87.3 % for M-CE; and 65.0 %, 94.4 %, and 85.1 % for M-NBI, respectively. The specificity of CE was significantly higher than that of M-CE ( P  = 0.034). The sensitivity of M-CE was significantly higher than that of CE ( P  = 0.026). In a comparison of positive and negative groups for the non-extension sign in SM-d cancer, SM invasion was significantly deeper in the positive group than in the negative group (3012.5 μm vs 2002.4 μm, respectively; P  < 0.0001) and the rate of lymphovascular invasion was significantly higher in the positive group than in the negative group (63.6 % vs 41.2 %, respectively; P  = 0.032).

CONCLUSIONS

 The non-extension sign offers high diagnostic specificity for SM-d cancer, and surgery should be considered in patients with a positive non-extension sign.

Classification of nuclear morphology in endocytoscopy of colorectal neoplasms

BACKGROUND AND AIMS

We investigated endocytoscopy (EC) findings that were considered risk factors for colorectal neoplasms and determined whether they could be used as new indices to identify carcinomas with massive submucosal invasion (SM-m) or worse outcomes.

METHODS

We performed a multivariate analysis of 8 factors on EC images to determine whether they were associated with SM-m or worse. Based on the results, we divided the EC3a category of the EC classification into low grade or high grade and investigated the diagnostic accuracy of this subclassification. In addition, we compared the diagnostic ability of EC for SM-m with that of other modalities (narrow-band imaging and pit pattern).

RESULTS

The multivariate analysis indicated that unclear glandular lumens (ULs), high degree of nuclear enlargement (HNE), and multilayered nuclei (MNs) were the most useful factors for the diagnosis of SM-m or worse. The odds ratios for these factors were 12.47, 12.29, and 10.48, respectively (P < .001). The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and positive likelihood ratio for the diagnostic accuracy of the EC3a subclassification were 88.9%, 91.3%, 75.0%, 96.6%, 90.8%, and 10.2, respectively (P < .001). The sensitivity, negative predictive value, and accuracy of EC were significantly higher than those of narrow-band imaging and pit pattern.

CONCLUSIONS

From the EC findings, the presence of ULs, HNE, and MNs are important risk factors for SM-m or worse outcomes. Furthermore, the EC3a subclassification taking these findings into consideration could be effective for the diagnosis of SM-m or worse. (Clinical trial registration number: UMIN 000014906.).

Narrow Band Imaging, Magnifying Chromoendoscopy, and Gross Morphological Features for the Optical Diagnosis of T1 Colorectal Cancer and Deep Submucosal Invasion: A Systematic Review and Meta-Analysis

OBJECTIVES

Optical diagnosis of T1 colorectal cancer (CRC) and T1 CRC with deep submucosal invasion is important in guiding the treatment strategy. The use of advanced imaging is not standard clinical practice in Western countries. A systematic review and meta-analysis were conducted comparing the accuracy of narrow band imaging (NBI), magnifying chromoendoscopy (MCE), and gross morphological features (GMF) seen with conventional view for the optical diagnosis of T1 CRC and deep submucosal invasion.

METHODS

A literature search identified studies on the optical diagnosis of T1 CRC and deep invasion using NBI, MCE, or GMF. Pooled estimates (PE) of sensitivity and specificity across studies reporting on NBI or MCE were compared using a random effects bivariate meta-regression approach, and a paired analysis focusing on studies that performed both techniques within the same patient was performed.

RESULTS

Thirty-three studies with 31,568 polyps were included. For the optical diagnosis of T1 CRC, both NBI (4 studies; PE 0.85, 95% confidence interval (CI) 0.75-0.91) and MCE (5 studies; PE 0.90, 95% CI 0.83-0.94) yielded higher sensitivity as compared with GMF (3 studies; range 0.21-0.46). No significant preference for NBI or MCE was found (sensitivity relative risk (RR) 0.93, 95% CI 0.79-1.09, P=0.37; specificity RR 0.98, 95% CI 0.86-1.11, P=0.74). Similarly, for the optical diagnosis of deep invasion, both NBI (13 studies; PE 0.77, 95% CI 0.68-0.84) and MCE (17 studies; PE 0.81, 95% 0.75-0.87) yielded higher sensitivity as compared with GMF (6 studies; range 0.18-0.88), and no significant preference for either NBI or MCE was found (sensitivity RR 0.92, 95% CI 0.76-1.11, P=0.36; specificity RR 1.00, 95% CI 0.96-1.04, P=0.92).

CONCLUSIONS

This review supports the use of advanced imaging techniques in preference to GMF to reduce the risk of performing piecemeal resection for T1 CRCs or unnecessary surgical referral for lesions amendable to endoscopic resection. A preference for either NBI or MCE could not be observed.

Malignancy in large colorectal lesions

CONTEXT

The size of colorectal lesions, besides a risk factor for malignancy, is a predictor for deeper invasion objectives: To evaluate the malignancy of colorectal lesions ≥20 mm.

METHODS

Between 2007 and 2011, 76 neoplasms ≥20 mm in 70 patients were analyzed.

RESULTS

The mean age of the patients was 67.4 years, and 41 were women. Mean lesion size was 24.7 mm ± 6.2 mm (range: 20 to 50 mm). Half of the neoplasms were polypoid and the other half were non-polypoid. Forty-two (55.3%) lesions were located in the left colon, and 34 in the right colon. There was a high prevalence of III L (39.5%) and IV (53.9%) pit patterns. There were 72 adenomas and 4 adenocarcinomas. Malignancy was observed in 5.3% of the lesions. Thirty-three lesions presented advanced histology (adenomas with high-grade dysplasia or early adenocarcinoma), with no difference in morphology and site. Only one lesion (1.3%) invaded the submucosa. Lesions larger than 30 mm had advanced histology (P = 0.001). The primary treatment was endoscopic resection, and invasive carcinoma was referred to surgery. Recurrence rate was 10.6%.

CONCLUSIONS

Large colorectal neoplasms showed a low rate of malignancy. Endoscopic treatment is an effective therapy for these lesions.

Short-term outcomes of colorectal endoscopic submucosal dissection performed by trainees

BACKGROUND

Colorectal endoscopic submucosal dissection (ESD) is a relatively new therapy that has been accepted as the most effective treatment procedure for superficial colorectal neoplasms. Given the increasing acceptance and use of this procedure worldwide, the outcomes of colorectal ESD performed by trainees should be understood from a practical perspective and for developing strategies to introduce ESD to trainees. This study aimed to evaluate the clinical outcomes of ESD when conducted by less-experienced endoscopists.

SUMMARY

We retrospectively reviewed the clinical outcomes of 164 patients with 164 colorectal neoplasms who underwent ESD carried out by 20 trainees performing their first colorectal ESDs between April 2005 and March 2012. For each operator, clinical data were collected between the first and 30th cases. For evaluating the technical aspects of the ESD procedure, the endoscopic characteristics of the lesions, procedure time, en bloc resection rate, R0 resection rate, invasion depth and complications were evaluated. The median procedure time was 95 min; about 75% of the lesions were resected within 120 min. Apparent perforation or electric damage in the muscularis propria was seen in 4% of lesions. In terms of factors with the potential to effect procedure time, lesion size and pathological invasion depth were significantly different between shorter and longer treatment times for granular-type laterally spreading tumors (LST).

KEY MESSAGES

A granular-type LST of <40 mm is a good lesion for introducing colorectal ESD to trainees. Trainees should have a strong ability to make a depth diagnosis before starting ESD.

Impact of clinical experience on type V pit pattern analysis using magnifying chromoendoscopy in early colorectal cancer: a cross-sectional interpretation test

Background

Although type V pit pattern analysis is effective in determining the invasion depth of early colorectal cancers, the clinical results may vary because findings are operator-dependent. This study aimed to assess the benefits of type V pit pattern analysis in estimating the invasion depth using magnifying chromoendoscopy compared to that with conventional colonoscopy.

Methods

A cross-sectional interpretation test involving 32 endoscopists with varying levels of experience performing colonoscopies was conducted. Fifty histopathologically diagnosed cases of intramucosal or submucosal cancer were selected retrospectively. The lesions were classified as superficial or deep by the endoscopists, based on magnifying chromoendoscopic and non-magnifying endoscopic images. The endoscopists were classified into 3 groups based on the number of colonoscopies performed: I (<500), II (501–5000), and III (>5000). Differences in the interpretation of invasion depth between group III and groups I and II were assessed using the Mann–Whitney U test.

Results

There was no significant difference in the median number of correct interpretations using non-magnifying endoscopic images among the groups. However, a significant difference (P = 0.007) was observed between the results of groups III and I when the analysis was performed using magnifying chromoendoscopic images.

Conclusions

When performed by less experienced endoscopists, pit pattern analysis of colonic lesions using magnifying chromoendoscopy is not a reliable modality for estimating invasion depth in early colorectal cancer.

Magnifying chromoendoscopy and endoscopic ultrasonography measure invasion depth of early stage colorectal cancer with equal accuracy on the basis of a prospective trial

BACKGROUND & AIMS

Magnifying chromoendoscopy (MC) and endoscopic ultrasonography (EUS) are used to estimate the depth of colorectal cancer (CRC) invasion, but it is not clear which procedure is more accurate. We performed a prospective study to compare MC and EUS.

METHODS

A total of 70 patients with an early stage flat CRC lesion were enrolled at 6 institutions in Japan and randomly assigned to groups assessed by MC followed by EUS or EUS followed by MC. Results from MC and EUS measurements of 66 lesions were included in the final analysis. The invasion depth of each lesion was measured by each procedure and categorized as mucosal to slight submucosal (depth <1000 μm) or deep submucosal (depth ≥ 1000 μm); measurements were compared with the final diagnosis on the basis of the pathology analysis. All participating examiners achieved a mean κ value ≥ 0.6 for both MC and EUS before this trial.

RESULTS

MC and EUS each measured the depth of lesion invasion with 71.2% accuracy (correctly for 47 of 66 lesions). MC identified lesions with deep submucosal invasion with 74.2% sensitivity and 68.6% specificity, whereas EUS identified them with 67.7% sensitivity and 74.3% specificity. The differences between MC and EUS measurements did not differ significantly. However, MC required significantly shorter observation time than EUS (361.7 ± 164.5 seconds vs 451.2 ± 209.4 seconds, P = .002).

CONCLUSIONS

MC and EUS are equally accurate in estimating the invasion depth of early stage CRC lesions. However, neither procedure has sufficient diagnostic accuracy to be used as the standard. University Hospital Medical Network Clinical Trials Registry, Number: UMIN 000005085.

Quantitative analysis of colorectal lesions observed on magnified endoscopy images

BACKGROUND

Various surface mucosal pit patterns, as recognized by endoscopists, correlate with the histologic features of colorectal cancers. We investigated whether magnified endoscopy images of these pit patterns could be analyzed quantitatively and thus facilitate computer-aided diagnosis of colorectal lesions.

METHODS

We applied both texture analysis and scale-invariant feature transform (SIFT) descriptors and discriminant analysis to magnified endoscopy images of 165 neoplastic colorectal lesions (pit patterns: type III(L)/IV, n = 44; type V(I)-mildly irregular, n = 36; type V(I)-severely irregular, n = 45; type V(N), n = 40) [histologic findings: tubular adenoma (TA), n = 56; carcinoma with intramucosal or even scant submucosal invasion (M/SM-s), n = 52, carcinoma with massive submucosal invasion (SM-m), n = 57]. We analyzed differences in pit pattern values and corresponding histologic values to determine whether the values were diagnostically meaningful.

RESULTS

Gray-level difference matrix (GLDM) inverse difference moment and spatial gray-level dependence matrix (SGLDM) local homogeneity values differed significantly between type III(L)/IV and type V(N) pit patterns. Values differed significantly for each analyzed feature between type III(L)/IV and type V(I)-severely irregular patterns and were high but descending for type III(L)/IV, type V(I)-mildly irregular, and type V(I)-severely irregular pit patterns (in that order). Similarly, texture analysis yielded high but descending values for TA, M/SM-s, and SM-m (in that order). Furthermore, SIFT descriptors and discriminant analysis yielded differences that were superior to those obtained by texture analyses.

CONCLUSIONS

Computer analysis of magnified endoscopy images for the diagnosis of colorectal lesions appears feasible. We anticipate further developments in the computer-aided diagnosis of pit patterns on magnified endoscopy images.