Effectiveness of narrow-band imaging magnification for invasion depth in early colorectal cancer

Comparative Cost Analysis Between Endoscopic Resection and Surgery for Submucosal Colorectal Cancer

BACKGROUND

There are few studies analyzing the cost of endoscopic resection and surgical resection in the treatment of submucosal colorectal cancer.

OBJECTIVE

The objective was to perform a detailed cost analysis of endoscopic resection and surgical resection for submucosal colorectal cancer.

DESIGN

This was a retrospective observational study.

SETTING

This study was conducted at a tertiary academic center.

PATIENTS

Medical records of 484 patients with submucosal colorectal cancer who underwent endoscopic resection or surgical resection between July 2003 and July 2015 were reviewed.

MAIN OUTCOME MEASUREMENTS

The total costs during index admission and follow-up as well as clinical outcomes between the 2 groups were compared in the whole cohort and propensity score-matched cohort.

RESULTS

In the propensity score-matched analysis ( n = 155 in each group), the endoscopic resection and surgical resection groups did not show significant differences in the rates of procedure-related adverse events (6.5% vs 3.9%; p = 0.304) and recurrence (0.6% vs 1.3%; p > 0.99). Readmission was more common in the endoscopic resection group (40.6% vs 11.0%; p < 0.001) because 64 (41.3%) patients underwent additional surgery for endoscopic noncurative resection. The endoscopic resection group had a lower cost during the index admission (1335.6 vs 6698.4 USD; p < 0.001), whereas the surgical resection group had a lower cost during follow-up (2488.7 vs 5035.7 USD; p < 0.001). The total cumulative cost was lower in the endoscopic resection group (6371.3 vs 9187.1 USD; p < 0.001). The same trend was observed in the whole cohort without propensity score matching.

LIMITATIONS

A limitation of this study was the retrospective nature of analysis.

CONCLUSIONS

The total cumulative cost for treatment and follow-up for submucosal colorectal cancer was lower in the endoscopic resection group, which had comparable oncologic outcomes as the surgical resection group. Endoscopic resection can be considered a cost-effective option for initial treatment for submucosal colorectal cancer. See Video Abstract at http://links.lww.com/DCR/B881 .

ANLISIS COMPARATIVO DE COSTOS ENTRE LA RESECCIN ENDOSCPICA Y LA CIRUGA PARA EL CNCER COLORRECTAL SUBMUCOSO

ANTECEDENTES: Existen pocos estudios que analizan el costo de la resección endoscópica y la resección quirúrgica en el tratamiento del cáncer colorrectal submucoso.OBJETIVO: El objetivo fue realizar un análisis detallado de costos tanto de la resección endoscópica y la resección quirúrgica para el cáncer colorrectal submucoso.DISEÑO: Este fue un estudio observacional retrospectivo.AJUSTE: Este estudio se realizó en un centro académico terciario.PACIENTES: Se revisaron las historias clínicas de 484 pacientes con cáncer colorrectal submucoso que fueron sometidos a resección endoscópica o resección quirúrgica entre julio de 2003 y julio de 2015.PRINCIPALES MEDICIONES DE RESULTADOS: Los costos totales durante la admisión índice y el seguimiento, así como los resultados clínicos entre los dos grupos, fueron comparados en toda la cohorte y la cohorte emparejada por puntuación de propensión.RESULTADOS: En el análisis emparejado por puntuación de propensión ( n = 155 en cada grupo), los grupos de resección endoscópica y resección quirúrgica no mostraron diferencias significativas en las tasas de eventos adversos relacionados con el procedimiento (6,5% vs 3,9%, p = 0,304) y recurrencia (0,6% vs 1,3%, p > 0,99). La readmisión fue más común en el grupo de resección endoscópica (40,6% vs 11,0%, p < 0,001) porque 64 (41,3%) pacientes fueron sometidos a una cirugía adicional para lograr la resección en aquellos casos en que la resección endoscópica no fue curativa. El grupo de resección endoscópica tuvo un costo menor durante el ingreso índice (1335.6 vs 6698.4 USD, p < 0.001), mientras que el grupo de resección quirúrgica tuvo un costo menor durante el seguimiento (2488.7 vs 5035.7 USD, p < 0.001). El costo total acumulado fue menor en el grupo de resección endoscópica (6371,3 vs 9187,1 USD, p < 0,001). La misma tendencia se observó en toda la cohorte sin emparejamiento por puntuación de propensión.LIMITACIONES: La naturaleza retrospectiva del análisis.CONCLUSIONES: El costo total acumulado para el tratamiento y seguimiento del cáncer colorrectal submucoso fue menor en el grupo de resección endoscópica, que tuvo resultados oncológicos comparables a los del grupo de resección quirúrgica. La resección endoscópica puede considerarse una opción rentable para el tratamiento inicial del cáncer colorrectal submucoso. Consulte Video Resumen en http://links.lww.com/DCR/B881 . (Traducción-Dr Osvaldo Gauto ).

Diagnostic efficacy of the Japan NBI Expert Team classification with dual-focus magnification for colorectal tumors

BACKGROUND AND AIMS

The Japan NBI Expert Team (JNET) classification is the first unified classification criteria for colorectal tumors using magnifying narrow-band imaging (NBI) in Japan. However, the diagnostic stratification ability of the JNET classification with dual-focus magnifying NBI (DF-JNET) has remained obscure. The aim of this study was to validate the diagnostic stratification ability of DF-JNET for colorectal tumors in two Japanese referral centers.

METHODS

A multicenter retrospective image evaluation study was conducted by three experienced endoscopists, including an original JNET member who was also involved in establishing the diagnostic criteria. A total of two images, namely, one representative non-magnified white light image and one representative DF-NBI image for each of the 557 consecutive lesions were used in the evaluation study. The diagnostic value of DF-JNET was calculated based on the evaluation data.

RESULTS

The sensitivity, specificity, positive and negative predictive values, and accuracy of DF-JNET Type 1 for differentiating between non-neoplastic and neoplastic lesions were 78.1%, 98.6%, 89.1%, 96.8%, and 95.9%, respectively; of Type 2A lesions for differentiating low-grade dysplasia from others were 98.0%, 76.5%, 94.9%, 89.7%, and 94.1%, respectively; of Type 2B lesions for differentiating high-grade dysplasia and shallow submucosal invasive carcinoma from others were 43.5%, 99.1%, 66.7%, 97.6%, and 96.8%, respectively; and of Type 3 lesions for differentiating deep submucosal invasive carcinoma from others were 83.3%, 99.5%, 62.5%, 99.8%, and 99.3%, respectively.

CONCLUSIONS

All DF-JNET types had an over 90% diagnostic accuracy for the histological prediction of colorectal tumors. DF-JNET might contribute to appropriate treatment choices, such as endoscopic resection or surgery, not only in Japan but also in Western countries in which the use of optical zoom endoscopy is limited.

Long-term outcomes of endoscopic submucosal dissection and transanal endoscopic microsurgery for the treatment of rectal tumors

BACKGROUND AND AIM

Endoscopic submucosal dissection and transanal endoscopic microsurgery are good options for the treatment of rectal adenomas and early rectal carcinomas, but whether long-term outcomes of these procedures are comparable is not known. The aim of this study was to address this question.

METHODS

A retrospective single-center study evaluating 98 consecutive procedures between June 2008 and December 2017 was performed in a tertiary cancer center. Consecutive patients who had undergone either endoscopic submucosal resection or transanal endoscopic microsurgery for rectal adenomas and early rectal carcinomas were evaluated, and long-term recurrence and complication rates were compared.

RESULTS

Both groups were similar regarding sex, age, preoperative surgical risk, and en bloc resection rate (95.7% in the endoscopic and 100% in the surgical group, P = 0.81). Mean follow-up period was 37.6 months. Lesions resected endoscopically were significantly larger (68.5 mm) than those resected by transanal resection (44.5 mm), P = 0.003. Curative resections occurred in 97.2% of endoscopic resections and 85.2% of the surgical ones (P = 0.04). Comparing resections that fulfilled histologic curative criteria, there were no recurrences in the endoscopic group (out of 69 cases) and two recurrences in the transanal group (8.3% of 24 cases), P = 0.06. Late complications occurred in 12.7% of endoscopic procedures and 25.9% of surgical procedures (P = 0.13).

CONCLUSIONS

In our experience, endoscopic submucosal resection seems to have advantages over transanal endoscopic microsurgery, with similar en bloc resection rate and lower rate of late complications and recurrences. Multicenter randomized controlled trials are needed to support our findings.

NBI utility in oncologic surgery: An organ by organ review

The main aims of the oncologic surgeon should be an early tumor diagnosis, complete surgical resection, and a careful post-treatment follow-up to ensure a prompt diagnosis of recurrence. Radiologic and endoscopic methods have been traditionally used for these purposes, but their accuracy might sometimes be suboptimal. Technological improvements could help the clinician during the diagnostic and therapeutic management of tumors. Narrow band imaging (NBI) belongs to optical image techniques, and uses light characteristics to enhance tissue vascularization. Because neoangiogenesis is a fundamental step during carcinogenesis, NBI could be useful in the diagnostic and therapeutic workup of tumors. Since its introduction in 2001, NBI use has rapidly spread in different oncologic specialties with clear advantages. There is an active interest in this topic as demonstrated by the thriving literature. It is unavoidable for clinicians to gain in-depth knowledge about the application of NBI to their specific field, losing the overall view on the topic. However, by looking at other fields of application, clinicians could find ideas to improve NBI use in their own specialty. The aim of this review is to summarize the existing literature on NBI use in oncology, with the aim of providing the state of the art: we present an overview on NBI fields of application, results, and possible future improvements in the different specialties.

Efficacy of linked colour imaging in magnifying chromoendoscopy with crystal violet staining: a pilot study

PURPOSE

Diagnosis of the depth of invasion is crucial in the endoscopic management of early colorectal cancer. Image-enhanced endoscopy (IEE) is a method for easily evaluating the depth of invasion. Linked colour imaging (LCI) is an IEE method that enables clearer identification of neoplastic lesions and mucosal inflammation. The aim of this experimental study was to explore the efficacy of LCI in vessel and pit pattern recognition when used in magnifying chromoendoscopy with crystal violet staining for superficial colorectal neoplasms.

METHODS

This was an experimental study. Colour difference (CD) values between the surrounding mucosa and vessels and pits were measured on white light (WLI), blue laser (BLI), and LCI images. The CD values of 10 neoplastic lesions were calculated and compared between WLI and the other techniques.

RESULTS

The CD value was 9.8 (interquartile range, 7.3-12.4) for WLI, 9.7 (6.7-13.4) for LCI, and 6.8 (5.1-9.3) for BLI. The CD value was statistically different between WLI and BLI but not between WLI and LCI. With regard to vessel description, the CD value was 7.5 (4.0-11.0) for WLI, 15.6 (11.6-23.9) for LCI, and 23.3 (15.8-30.4) for BLI.

CONCLUSIONS

LCI provides more diagnostic information than other light modes. Further, it is superior to the other techniques in terms of vessel visibility and is comparable to them in terms of pit recognition. These unique features of LCI may lead to its use as an alternative to WLI and BLI for pit and vessel pattern evaluation in the future.

Comparison of the diagnostic performance between magnifying chromoendoscopy and magnifying narrow-band imaging for superficial colorectal neoplasms: an online survey

BACKGROUND AND AIMS

Magnifying narrow-band imaging (mag-NBI) and magnifying chromoendoscopy using crystal violet staining for pit pattern analysis (pit pattern) is highly accurate for diagnosing invasion depth of superficial colorectal neoplasms. However, NBI and pit pattern have not been compared.

METHODS

We conducted an online survey of endoscopists interested in image-enhanced endoscopy. Still images using white light, mag-NBI, and pit pattern were collected from lesions diagnosed at the National Cancer Center Hospital (NCCH), Tokyo, Japan. Sixty endoscopists from outside NCCH who typically use magnifying endoscopy were recruited for this survey. We assessed the diagnostic accuracy using receiver operating characteristic (ROC) analysis based on a calculation of the area under the ROC curve.

RESULTS

One hundred early colorectal neoplasms were selected for this survey. Histopathology revealed that, although 67 of the lesions had high-grade dysplasia or carcinoma with superficial submucosal (SM-s) invasion, the other 33 lesions had a carcinoma with deep submucosal invasion (SM-d). Comparing the area under the ROC curve from mag-NBI with that of pit pattern, the latter showed significantly higher diagnostic accuracy for depth invasion (0.83 [95% CI, 0.81-0.85] for mag-NBI, 0.88 [95% CI, 0.85-0.89] for pit pattern, P = .013).

CONCLUSIONS

Pit pattern should be the first choice for diagnosing invasion depth as the most reliable modality rather than mag-NBI.

Endoscopic resection of high-risk T1 colorectal carcinoma prior to surgical resection has no adverse effect on long-term outcomes

OBJECTIVE

It is difficult to predict the presence of histological risk factors for lymph node metastasis (LNM) before endoscopic treatment of T1 colorectal cancer (CRC). Therefore, endoscopic therapy is propagated to obtain adequate histological staging. We examined whether secondary surgery following endoscopic resection of high-risk T1 CRC does not have a negative effect on patients' outcomes compared with primary surgery.

DESIGN

Patients with T1 CRC with one or more histological risk factors for LNM (high risk) and treated with primary or secondary surgery between 2000 and 2014 in 13 hospitals were identified in the Netherlands Cancer Registry. Additional data were collected from hospital records, endoscopy, radiology and pathology reports. A propensity score analysis was performed using inverse probability weighting (IPW) to correct for confounding by indication.

RESULTS

602 patients were eligible for analysis (263 primary; 339 secondary surgery). Overall, 34 recurrences were observed (5.6%). After adjusting with IPW, no differences were observed between primary and secondary surgery for the presence of LNM (OR 0.97; 95% CI 0.49 to 1.93; p=0.940) and recurrence during follow-up (HR 0.97; 95% CI 0.41 to 2.34; p=0.954). Further adjusting for lymphovascular invasion, depth of invasion and number of retrieved lymph nodes did not alter this outcome.

CONCLUSIONS

Our data do not support an increased risk of LNM or recurrence after secondary surgery compared with primary surgery. Therefore, an attempt for an en-bloc resection of a possible T1 CRC without evident signs of deep invasion seems justified in order to prevent surgery of low-risk T1 CRC in a significant proportion of patients.

Application of image-enhanced endoscopy in diagnosis of colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies, and in China the incidence and mortality of CRC are among the top in the world. Early diagnosis of CRC can improve the prognosis significantly. Image enhancement techniques have already been applied to endoscopy, including narrow band imaging, flexible spectral imaging, i-Scan, and blue laser imaging endoscopy system. These techniques, combined with image pre-processing or post-processing method, might improve the detection of lesions by enhancing the color contrast between lesions and their surrounding mucosa. Nowadays, several classification systems for colorectal tumors have been established based on the surface pattern and microvascular morphology of lesions. Image enhancement technology might display the microvascular structures more clearly and determine the malignancy and infiltrating depth of lesions more accurately.

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.

Digital Chromoendoscopy With i-Scan for In Vivo Prediction of Advanced Colorectal Neoplasia: A Multicenter Study

BACKGROUND

Recent studies have analyzed the potential of advanced endoscopic imaging techniques for differentiating hyperplastic and adenomatous colorectal lesions. Latest endoscopic resection techniques now also allow for treatment of more advanced staged lesions including treatment of early cancerous lesions.

AIMS

To assess the potential of the i-scan technology to differentiate between adenomatous polyps and advanced staged neoplasia.

METHODS

Consecutive patients undergoing colonoscopy at a tertiary referral center were included. After a dedicated training, participating endoscopists underwent a review of 298 unknown images of colonic lesions to assess colorectal lesion histology.

RESULTS

Overall accuracy for prediction of advanced staged neoplasia was 92.2% (sensitivity: 94.2%, specificity 90.9%). The positive and negative predictive values were calculated as 87.5% and 95.9%, respectively. The κ-value for differentiating adenomatous polyps and advanced staged neoplasia was 0.8193 (0.7894 to 0.8492). Intraobserver agreement was calculated with a κ-value of 0.9301 (0.8875 to 0.9727).

CONCLUSIONS

Accurate interpretation of i-scan images for prediction of advanced colorectal neoplasia can successfully be performed even by nonexpert endoscopists with a high overall accuracy and excellent interobserver agreements.

Usefulness of dilated blood vessels in the tumor periphery for assessing the invasion depth of small-sized depressed colorectal cancer

The relationship between dilated blood vessels in the tumor periphery and the tumor invasion depth is unclear. Therefore, the present study aimed to clarify the relationship between dilated blood vessels and the invasion depth of small-sized (<30 mm) colorectal cancer (CRC), and its implications on endoscopic treatment.We performed a single-arm observational study of the diagnostic accuracy of the existence of dilated vessels in the tumor periphery of CRC lesions as an indicator of submucosal deep (SM-d, ≥1000 μm) carcinomas. Lesions were classified into two groups based on the existence of dilated vessels by two experienced endoscopists. The clinicopathological features, invasion depth, and lymphovascular invasion/poorly differentiated clusters were analyzed in all resected specimens.Four hundred and two consecutive small-sized CRC lesions were included. The dilated vessels were observed in 96/402 (24%) lesions, and most of them (93/96) were found in depressed lesions. In depressed lesions, the histopathological diagnosis of the dilated vessels group showed SM-d or deeper invasion in 84/93 (90%) cases, whereas 3/20 (15%) had SM-d invasion in the nondilated vessels group (P < 0.001). When the dilated vessels were used as an indicator of SM-d or deeper invasion in depressed lesions, the sensitivity was 95.6%, specificity was 66.7%, and accuracy was 90.2%. No correlation was observed between the existence of dilated vessels and the lesion site, lesion diameter, and lymphovascular invasion/poorly differentiated cluster.The existence of dilated blood vessels in the tumor periphery suggests SM-d or deeper invasion in depressed lesions.

Toxicity studies of coumarin 6-encapsulated polystyrene nanospheres conjugated with peanut agglutinin and poly(N-vinylacetamide) as a colonoscopic imaging agent in rats

We are investigating an imaging agent that detects early-stage primary colorectal cancer on the mucosal surface in real time under colonoscopic observation. The imaging agent, which is named the nanobeacon, is fluorescent nanospheres conjugated with peanut agglutinin and poly(N-vinylacetamide). Its potential use as an imaging tool for colorectal cancer has been thoroughly validated in numerous studies. Here, toxicities of the nanobeacon were assessed in rats. The nanobeacon was prepared according to the synthetic manner which is being established as the Good Manufacturing Practice-guided production. The rat study was performed in accordance with Good Laboratory Practice regulations. No nanobeacon treatment-related toxicity was observed. The no observable adverse effect levels (NOAEL) of the nanobeacon in 7-day consecutive oral administration and single intrarectal administration were estimated to be more than 1000mg/kg/day and 50mg/kg/day, respectively. We concluded that the nanobeacon could be developed as a safe diagnostic agent for colonoscopy applications.

FROM THE CLINICAL EDITOR

Colon cancer remains a major cause of death. Early detection can result in early treatment and thus survival. In this article, the authors tested potential systemic toxicity of coumarin 6-encapsulated polystyrene nanospheres conjugated with peanut agglutinin (PNA) and poly(N-vinylacetamide) (PNVA), which had been shown to bind specifically to colonic cancer cells and thus very promising in colonoscopic detection of cancer cells.

Observation of microvessels and invasion in early colorectal neoplasms on narrow band imaging: combination with CD34 and matrix metalloproteinase-7 expression

OBJECTIVE

The study aims to clarify the role of narrow band imaging (NBI) in the prediction of invasion depth and the formation of lesion appearance under NBI with immunohistochemical analysis.

MATERIALS AND METHODS

As a prospective single-center study, Sano's classification of capillary pattern (CP) was applied to differentiate early colorectal neoplasms under NBI observation. Only lesions with CP type III were analyzed, compared with final histologic findings, and further immunohistochemical analysis with CD34 and matrix metalloproteinase-7 (MMP-7) was performed.

RESULTS

As for the 203 cases of CP type III lesions, the sensitivity, specificity, and accuracy for CP type IIIA/IIIB were, respectively, 88.4, 93.6, and 92.5% to differentiate high-grade neoplasia or slight submucosal invasive carcinoma from deep submucosal invasive carcinoma. NBI prediction for invasion depth corresponded to immunohistochemical outcomes of CD34 and MMP-7, which might explain the reason why CP type IIIB displays nearly avascular or loose microvascular areas on the lesion surface.

CONCLUSION

NBI is of excellent use in predicting invasion depth for early colorectal neoplasms, and positive expression of MMP-7 is associated with the appearance of CP type IIIB.

Specificity of lectin-immobilized fluorescent nanospheres for colorectal tumors in a mouse model which better resembles the clinical disease

We have been investigating an imaging agent that enables real-time and accurate diagnosis of early colorectal cancer at the intestinal mucosa by colonoscopy. The imaging agent is peanut agglutinin-immobilized polystyrene nanospheres with surface poly(N-vinylacetamide) chains encapsulating coumarin 6. Intracolonically-administered lectin-immobilized fluorescent nanospheres detect tumor-derived changes through molecular recognition of lectin for the terminal sugar of cancer-specific antigens on the mucosal surface. The focus of the present study was to evaluate imaging abilities of the nanospheres in animal models that reflect clinical environments. We previously developed an orthotopic mouse model with human colorectal tumors growing on the mucosa of the descending colon to better resemble the clinical disease. The entire colon of the mice in the exposed abdomen was monitored in real time with an in vivo imaging apparatus. Fluorescence from the nanospheres was observed along the entire descending colon after intracolonical administration from the anus. When the luminal side of the colon was washed with phosphate-buffered saline, most of the nanospheres were flushed. However, fluorescence persisted in areas where cancer cells were implanted. Histological evaluation demonstrated that tumors were present in the mucosal epithelia where the nanospheres fluoresced. In contrast, no fluorescence was observed when control mice, without tumors were tested. The lectin-immobilized fluorescent nanospheres were tumor-specific and remained bound to tumors even after vigorous washing. The nanospheres nonspecifically bound to normal mucosa were easily removed through mild washing. These results indicate that the nanospheres combined with colonoscopy, will be a clinically-valuable diagnostic tool for early-stage primary colon carcinoma.

Magnifying narrow-band imaging of surface patterns for diagnosing colorectal cancer

Narrow-band imaging (NBI) of surface microvessels of colorectal lesions is useful for differentiating neoplasms from non-neoplasms and for predicting histopathological diagnosis. Furthermore, NBI of surface microstructure, or 'surface pattern', is valuable for predicting histopathology in colorectal cancer. The aim of the present study was to investigate whether surface patterns could be used to predict invasion depth in colorectal cancer, and to compare the accuracy of surface pattern diagnosis in each macroscopic type. Between January 2010 and March 2011, a series of 357 consecutive patients with 378 early colorectal cancers were observed by magnifying NBI and the surface pattern was prospectively evaluated. Surface pattern was classified into 3 types: type I, microstructure was clearly recognised with uniform arrangement and form; type II, microstructure was obscured with heterogeneous arrangement and form; and type III, microstructure was invisible. We also classified the macroscopic type into 3 categories: depressed, protruded and flat elevated. Assuming that type III was an index of massively invasive lesions in the submucosal layer (SMm), the sensitivity, specificity and accuracy were 56.9, 91.7 and 85.7%, respectively. The sensitivity, specificity and accuracy of type III for the diagnosis of SMm in each macroscopic type were: depressed, 88.9, 40.0 and 63.2%, respectively; protruded: 34.8, 96.4 and 90.0%, respectively; and flat elevated, 54.2, 92.7 and 85.0%, respectively. These results suggest that the diagnostic accuracy of surface pattern was insufficient and particularly poor for depressed-type lesions.

Characteristic magnifying narrow-band imaging features of colorectal tumors in each growth type

PURPOSE

We investigated the surface characteristics and vascular patterns of colorectal tumors according to growth type by means of magnifying narrow-band imaging (NBI).

METHODS

Four hundred ninety-seven colorectal tumors larger than 10 mm (204 tubular adenomas [TAs], 199 frankly invasive intramucosal carcinomas to shallow invasive submucosal [M/SM-s] carcinomas, and 94 deeply invasive submucosal [SM-d] carcinomas) were analyzed. These colorectal tumors were classified according to growth type as follows: polypoid type, n = 224; laterally spreading tumor-granular (LST-G) type, n = 133; and LST-non-granular (LST-NG) type, n = 140. Surface and vascular patterns were evaluated in relation to histology and growth type.

RESULTS

The absent and irregular surface patterns were observed in approximately 40 % of the SM-d carcinomas of the polypoid and LST-G type. The unclear surface pattern was more frequent in tumors of the LST-NG type than in those of other growth types, regardless of histology. Among TAs and M/SM-s carcinomas, the dense vascular pattern was most frequent in polypoid type, the dense and corkscrew vascular patterns were most frequent in the LST-G type, and the honeycomb and avascular and/or fragmentary patterns were most frequent in the LST-NG type. The avascular and/or fragmentary vessel pattern was more frequent in SM-d carcinomas than in TA and M/SM-s carcinomas, regardless of growth type.

CONCLUSIONS

A part of LST-NG was difficult to identify the NBI magnifying surface pattern. Although NBI magnifying findings were almost same in each type lesion in SM-d lesion, those of LST-NG were different from those of LST-G and polypoid type in M/SM-s lesion.

Miniprobe endoscopic ultrasonography has limitations in determining the T stage in early colorectal cancer

Background/Aims

Mini-probe endoscopic ultrasonography (mEUS) is a useful diagnostic tool for accurate assessment of tumor invasion. The aim of this study was to estimate the accuracy of mEUS in patients with early colorectal cancer (ECC).

Methods

Ninety lesions of ECC underwent mEUS for pre-treatment staging. We divided the lesions into either the mucosal group or the submucosal group according to the mEUS findings. The histological results of the specimens were compared with the mEUS findings.

Results

The overall accuracy for assessing the depth of tumor invasion (T stage) was 84.4% (76/90). The accuracy of mEUS was significantly lower for submucosal lesions compared to mucosal lesions (p=0.003) and it was lower for large tumors (≥2 cm) (p=0.034). The odds ratios of large tumors and submucosal tumors affecting the accuracy of T staging were 3.46 (95% confidence interval [CI], 1.05 to 11.39) and 6.25 (95% CI, 1.85 to 25.14), respectively. When submucosal tumors were combined with large size, the odds ratio was 14.67 (95% CI, 1.46 to 146.96).

Conclusions

The overall accuracy of T stage determination with mEUS was considerably high in patients with ECC; however, the accuracy decreased when tumor size was >2 cm or the tumor had invaded the submucosal layer.

Image-enhanced endoscopy for diagnosis of colorectal tumors in view of endoscopic treatment

Recently, image-enhanced endoscopy (IEE) has been used to diagnose gastrointestinal tumors. This method is a change from conventional white-light (WL) endoscopy without dyeing solution, requiring only the push of a button. In IEE, there are many advantages in diagnosis of neoplastic tumors, evaluation of invasion depth for cancerous lesions, and detection of neoplastic lesions. In narrow band imaging (NBI) systems (Olympus Medical Co., Tokyo, Japan), optical filters that allow narrow-band light to pass at wavelengths of 415 and 540 nm are used. Mucosal surface blood vessels are seen most clearly at 415 nm, which is the wavelength that corresponds to the hemoglobin absorption band, while vessels in the deep layer of the mucosa can be detected at 540 nm. Thus, NBI also can detect pit-like structures named surface pattern. The flexible spectral imaging color enhancement (FICE) system (Fujifilm Medical Co., Tokyo, Japan) is also an IEE but different to NBI. FICE depends on the use of spectral-estimation technology to reconstruct images at different wavelengths based on WL images. FICE can enhance vascular and surface patterns. The autofluorescence imaging (AFI) video endoscope system (Olympus Medical Co., Tokyo, Japan) is a new illumination method that uses the difference in intensity of autofluorescence between the normal area and neoplastic lesions. AFI light comprises a blue light for emitting and a green light for hemoglobin absorption. The aim of this review is to highlight the efficacy of IEE for diagnosis of colorectal tumors for endoscopic treatment.

Comparison of diagnostic accuracies of various endoscopic examination techniques for evaluating the invasion depth of colorectal tumors

This study was designed to assess the clinical value of magnifying endoscopy combined with EUS for estimating the invasion depth of colorectal tumors. We studied 168 colorectal adenomas and carcinomas that were sequentially examined by conventional endoscopy followed by magnifying endoscopy and EUS in the same session to evaluate invasion depth. Endoscopic images obtained by each technique were reassessed by 3 endoscopists to determine whether endoscopic resection (adenoma, mucosal cancer, or submucosal cancer with slight invasion) or colectomy (submucosal cancer with massive invasion or advanced cancer) was indicated. The accuracy of differential diagnosis was compared among the examination techniques. The rate of correct differential diagnosis according to endoscopic examination technique was similar. The proportion of lesions that were difficult to diagnose was significantly higher for EUS (15.5%) than for conventional endoscopy and magnifying endoscopy. Among lesions that could be diagnosed, the rate of correct differential diagnosis was the highest for EUS (89.4%), but did not significantly differ among three endoscopic examination techniques. When it is difficult to evaluate the invasion depth of colorectal tumors on conventional endoscopy alone, the combined use of different examination techniques such as EUS may enhance diagnostic accuracy in some lesions.

Desmoplastic reaction in biopsy specimens of early colorectal cancer: a Japanese prospective multicenter study

We previously reported that detection of desmoplastic reaction (DR) in pretreatment biopsy specimens was useful for predicting the depth of submucosal invasion (SM depth) in nonpedunculated early colorectal cancers (ECRCs) in a retrospective study. Here, we performed a prospective multicenter study for verification of our previous findings. Subjects were diagnosed with ECRC by endoscopy, and with adenocarcinoma from the biopsy specimens. Eleven institutions affiliated with the Japanese Society for Cancer of the Colon and Rectum participated in this collaborative study. A total of 112 patients with ECRC were enrolled. For nonpedunculated ECRCs, presence of DR was significantly correlated with SM depth. The sensitivity and specificity of detection of DR for prediction of pSM2 (tumor invasion ≥1000 µm) in nonpedunculated ECRCs were 68.6% and 92.0%, respectively. Evaluation of DR in pretreatment biopsy specimens may be useful for the clinicopathological diagnosis of colorectal carcinoma with massive invasion into the submucosal layer.

The detection of surface patterns by flexible spectral imaging color enhancement without magnification for diagnosis of colorectal polyps

PURPOSE

Flexible spectral imaging color enhancement (FICE), or image-enhanced endoscopy, can enhance visualization of surface and vascular patterns of colorectal polyps. Resolution of FICE has recently been improved. We evaluated diagnostic accuracy for neoplastic and non-neoplastic colorectal polyp differentiation with detection of surface patterns by FICE without magnification.

METHODS

Retrospective analysis of 151 colorectal polyps evaluated by FICE without magnification was performed. Neoplastic surface patterns were defined as tubular and oval pit. We aimed to determine sensitivity, specificity, positive and negative predictive values (PPV and NPV), and accuracy in correlating diagnosis by FICE without magnification with histology. Moreover, findings were compared to those of white-light endoscopy (WL) and chromoendoscopy (CHR).

RESULTS

Of the 151 colorectal polyps, 95 were identified as neoplastic and 56 were identified as non-neoplastic. FICE without magnification had a sensitivity of 89.4%, specificity of 89.2%, PPV of 93.4%, NPV of 83.3%, and accuracy of 89.4%. The accuracy of FICE value was higher than that of WL (sensitivity of 74.7%, specificity of 73.2%, PPV of 82.5%, NPV of 63.0%, and accuracy of 74.1%) and was worse than that of CHR (sensitivity of 96.8%, specificity of 89.2%, PPV of 93.9%, NPV of 96.1%, and accuracy of 94.7%). Imaging evaluation was validated by inter-/intra-observer measurements, demonstrating consistent results.

CONCLUSIONS

The detection of surface patterns by FICE without magnification is useful for differential diagnosis of colorectal polyps. We believe that FICE without magnification is more convenient and easier method than CHR.

Comparison of magnifying chromoendoscopy and narrow-band imaging in estimation of early colorectal cancer invasion depth: a pilot study

BACKGROUND

Several previous studies have identified narrow-band imaging (NBI) with magnification as being useful in evaluating early colorectal cancer invasion depth, but comparative diagnostic accuracy of invasion depth between pit pattern analysis using magnifying chromoendoscopy and NBI remains unclear. The aim of this retrospective study was to compare NBI and pit pattern analysis using magnifying chromoendoscopy in estimating early colorectal cancer invasion depth and to assess interobserver agreement.

PATIENTS AND METHODS

We analyzed a total of 72 early colorectal cancers in 72 patients fulfilling the inclusion criteria. Each lesion image was subsequently reviewed by two experienced colonoscopists (A, B) and then classified clinically based on invasive/non-invasive pattern and Sano's capillary pattern classification with a five-point scale of confidence.

RESULTS

In terms of diagnostic accuracy with confidence for A and B, the areas under the receiver operating characteristics curve were 0.84 and 0.81 for pit pattern analysis and 0.82 and 0.79 for NBI, respectively. Interobserver agreement for the diagnosis of submucosal deep (>1000 µm) invasion was evaluated for both modalities and indicated substantial agreement with pit pattern analysis (κ = 0.63) and moderate agreement with NBI (κ = 0.44).

CONCLUSION

  Estimating invasion depth of early colorectal cancer using NBI appeared to have been comparable to pit pattern analysis, but there was greater interobserver variability using NBI.

Narrow-band imaging endoscopy with and without magnification in diagnosis of colorectal neoplasia

AIM: To evaluate the diagnostic efficacies of narrow-band imaging (NBI) endoscopy with and without high magnification in distinguishing neoplasia from non-neoplasia colorectal lesions.

METHODS: A total of 118 patients with 123 colorectal lesions examined by NBI endoscopy in the Zhejiang Provincial People’s Hospital from September 2008 to April 2010 were enrolled in this study. These lesions were classified by pit pattern and capillary pattern, and then assessed by histopathology.

RESULTS: Ten lesions not meeting the diagnostic criteria were excuded, the overall diagnostic accuracy of NBI endoscopy in distinguishing neoplasia from non-neoplasia colorectal lesions was 91.2% (103/113), and that of NBI endoscopy with and without high magnification was 93.0% (40/43) and 90.0% (63/70), respectively. Both were significantly higher than that of conventional colonoscopy reported in the literature (P < 0.05), but there was no significant difference between the two groups (P > 0.05).

CONCLUSION: Besides NBI magnifying endoscopy, NBI endoscopy without magnification may also be used to distinguish neoplasia from non-neoplasia colorectal lesions.