Early colorectal cancer: concept, diagnosis, and management

Implementation of an organized colorectal cancer screening program through quantitative fecal immunochemical test followed by colonoscopy in an urban low-income community: Guidance and strategies

Fecal Immunochemical Test (FIT) followed by a colonoscopy is an efficacious strategy to improve the adenoma detection rate and Colorectal Cancer (CRC). There is no organized national screening program for CRC in Brazil. The aim of this research was to describe the implementation of an organized screening program for CRC through FIT followed by colonoscopy, in an urban low-income community of São Paulo city. The endpoints of the study were: FIT participation rate, FIT positivity rate, colonoscopy compliance rate, Positive Predictive Values (PPV) for adenoma and CRC, and the rate of complications. From May 2016 to October 2019, asymptomatic individuals, 50-75 years old, received a free kit to perform the FIT. Positive FIT (≥ 50 ng/mL) individuals were referred to colonoscopy. 10,057 individuals returned the stool sample for analysis, of which (98.2%) 9,881 were valid. Women represented 64.8% of the participants. 55.3% of individuals did not complete elementary school. Positive FIT was 7.8% (776/9881). The colonoscopy compliance rate was 68.9% (535/776). There were no major colonoscopy complications. Adenoma were detected in 63.2% (332/525) of individuals. Advanced adenomatous lesions were found in 31.4% (165/525). CRC was diagnosed in 5.9% (31/525), characterized as adenocarcinoma: in situ in 3.2% (1/31), intramucosal in 29% (9/31), and invasive in 67.7% (21/31). Endoscopic treatment with curative intent for CRC was performed in 45.2% (14/31) of the cases. Therefore, in an urban low-income community, an organized CRC screening using FIT followed by colonoscopy ensued a high participation rate, and high predictive positive value for both, adenoma and CRC.

Molecular and clinicopathological differences between depressed and protruded T2 colorectal cancer

Background

Colorectal cancer (CRC) can be classified into four consensus molecular subtypes (CMS) according to genomic aberrations and gene expression profiles. CMS is expected to be useful in predicting prognosis and selecting chemotherapy regimens. However, there are still no reports on the relationship between the morphology and CMS.

Methods

This retrospective study included 55 subjects with T2 CRC undergoing surgical resection, of whom 30 had the depressed type and 25 the protruded type. In the classification of the CMS, we first defined cases with deficient mismatch repair as CMS1. And then, CMS2/3 and CMS4 were classified using an online classifier developed by Trinh et al. The staining intensity of CDX2, HTR2B, FRMD6, ZEB1, and KER and the percentage contents of CDX2, FRMD6, and KER are input into the classifier to obtain automatic output classifying the specimen as CMS2/3 or CMS4.

Results

According to the results yielded by the online classifier, of the 30 depressed-type cases, 15 (50%) were classified as CMS2/3 and 15 (50%) as CMS4. Of the 25 protruded-type cases, 3 (12%) were classified as CMS1 and 22 (88%) as CMS2/3. All of the T2 CRCs classified as CMS4 were depressed CRCs. More malignant pathological findings such as lymphatic invasion were associated with the depressed rather than protruded T2 CRC cases.

Conclusions

Depressed-type T2 CRC had a significant association with CMS4, showing more malignant pathological findings such as lymphatic invasion than the protruded-type, which could explain the reported association between CMS4 CRC and poor prognosis.

Endoscopic treatment of early colorectal cancer

Early colorectal neoplasia is a localized precancerous lesion of the large intestine associated with negligible risk of lymphatic or systemic dissemination. Early neoplasia consists of adenoma with low- and high-grade dysplasia, intramucosal carcinoma and superficially invasive cancer without other high-risk features. In the majority of cases, early neoplastic lesions are detected by colonoscopy and treated by means of endoscopy resection replacing surgical treatment. Risk of invasive cancer should be stratified during diagnostic colonoscopy using morphological classifications and then, appropriate resection technique (endoscopic polypectomy, endoscopic mucosal resection, endoscopic submucosal dissection or full-thickness resection) is used. Success of endoscopic resection is assessed by histological examination of the resected specimen and in some cases, additional surgical resection with lymphadenectomy should be performed. Colonoscopic surveillance is needed due to the risk of local recurrence and metachronous lesions.

The Differential Diagnosis of Colorectal Polyps Using Colon Capsule Endoscopy

Objective Although colorectal polyps (CPs) can be observed with colon capsule endoscopy (CCE), it is difficult to determine the type of polyp using CCE. The objective of this study was to differentiate adenomatous polyps (APs) from hyperplastic polyps (HPs) with CCE. Methods In this single-center retrospective study, an analysis was conducted on the same CPs with both CCE and colonoscopy (CS) and histopathologically diagnosed as AP or HP. The color difference (ΔE) between the polyp surface and the surrounding mucosa was calculated using the CIE1976 L*a*b* color space method on white light (WL), flexible spectral imaging color enhancement (FICE), and blue mode (BM) CP images. We investigated the ability of the ratio of the color differences (ΔE') to differentiate between APs and HPs. Results The size of all 51 polyps (34 APs, 17 HPs) was 7.5±4.6 mm with CCE and 7.3±4.2 mm with CS, and this difference was not significant (p=0.28). The FICEΔE' of APs was 3.3±1.8, which was significantly higher than the FICEΔE' of HPs (1.3±0.6; p<0.001). A receiver operating characteristic analysis showed that FICEΔE' was useful for differentiating between APs and HPs, with an area under the curve of 0.928 (95% confidence interval, 0.843-1). The sensitivity was 91.2%, and the specificity was 88.2% with a cut-off value of 1.758. Conclusion Using FICE on CCE images of CPs and applying the CIELAB color space method, we were able to differentiate between APs and HPs with high accuracy. This method has the potential to reduce unnecessary CS procedures.

Does Additional Laparoscopic-Assisted Surgery after Endoscopic Submucosal Dissection Affect Short Outcomes in Patients with Stage T1 Colorectal Cancer? A Propensity Score-Based Analysis

BACKGROUND

Additional surgery is necessary in cases with non-curative endoscopic submucosal dissection. It is still unknown whether preceding endoscopic submucosal dissection (ESD) for T1 colorectal carcinoma affects the short outcomes of patients who underwent additional surgery or not as compared with surgery alone without ESD.

METHODS

Patients (101 pairs) with T1 colorectal cancer who underwent additional laparoscopic-assisted surgery after endoscopic submucosal dissection (additional surgery group, n = 101) or laparoscopic-assisted surgery alone (surgery alone group, n = 101) were matched (1:1). Short-term morbidity, operation outcomes, and lymph node metastasis of the resected specimen were compared.

RESULTS

There were no significant differences between the additional laparoscopic-assisted surgery and laparoscopic-assisted surgery alone groups in lymph node metastasis (9.9 vs. 5.9%, respectively, p = 0.297), operative time (147.76 ± 52.00 min vs. 156.50 ± 54.28 min, p = 0.205), first flatus time (3.56 ± 1.10 days vs. 3.63 ± 1.05 days, p = 0.282), first stool time (4.30 ± 1.04 days vs. 4.39 ± 1.22 days, p = 0.293), time to intake (5.00 ± 1.18 days vs. 5.25 ± 1.39 days, p = 0.079), blood loss (44.75 ± 45.40 mL vs. 60.40 ± 78.98 mL, p = 0.603), harvest lymph nodes (18.74 ± 7.22 vs. 20.32 ± 9.69, p = 0.438), postoperative surgical complications (p = 0.733), and postoperative length of hospital stay (8.68 ± 4.00 days vs. 8.39 ± 1.94 days, p = 0.401).

CONCLUSION

ESD did not increase the difficulty of additional laparoscopic-assisted surgery, hospital stay, or the incidence of postoperative complications. Additional laparoscopic-assisted surgery is safe and recommended for patients with T1 cancer at high risk of lymph node metastasis and residual cancer after non-curative ESD.

Development of a Novel Prognostic Model for Predicting Lymph Node Metastasis in Early Colorectal Cancer: Analysis Based on the Surveillance, Epidemiology, and End Results Database

Background

Identification of a simplified prediction model for lymph node metastasis (LNM) for patients with early colorectal cancer (CRC) is urgently needed to determine treatment and follow-up strategies. Therefore, in this study, we aimed to develop an accurate predictive model for LNM in early CRC.

Methods

We analyzed data from the 2004-2016 Surveillance Epidemiology and End Results database to develop and validate prediction models for LNM. Seven models, namely, logistic regression, XGBoost, k-nearest neighbors, classification and regression trees model, support vector machines, neural network, and random forest (RF) models, were used.

Results

A total of 26,733 patients with a diagnosis of early CRC (T1) were analyzed. The models included 8 independent prognostic variables; age at diagnosis, sex, race, primary site, histologic type, tumor grade, and, tumor size. LNM was significantly more frequent in patients with larger tumors, women, younger patients, and patients with more poorly differentiated tumor. The RF model showed the best predictive performance in comparison to the other method, achieving an accuracy of 96.0%, a sensitivity of 99.7%, a specificity of 92.9%, and an area under the curve of 0.991. Tumor size is the most important features in predicting LNM in early CRC.

Conclusion

We established a simplified reproducible predictive model for LNM in early CRC that could be used to guide treatment decisions. These findings warrant further confirmation in large prospective clinical trials.

A Focused Review on Advances in Risk Stratification of Malignant Polyps

Colorectal cancer is the third most common cancer in both men and women in the United States, with most cases arising from precursor adenomatous polyps. Colorectal malignant polyps are defined as cancerous polyps that consist of tumor cells invading through the muscularis mucosae into the underlying submucosa (pT1 tumor). It has been reported that approximately 0.5-8.3% of colorectal polyps are malignant polyps, and the potential for lymph node metastasis in these polyps ranges from 8.5% to 16.1%. Due to their clinical significance, recognition of malignant polyps is critical for clinical teams to make treatment decisions and establish appropriate surveillance schedules after local excision of the polyps. There is a rapidly developing interest in malignant polyps within the literature as a result of an increasing number of identifiable adverse histologic features and recent advancements in endoscopic treatment techniques. The purpose of this paper is to have a focused review of the recent histopathologic literature of malignant polyps.

Case of Colorectal Cancer After Cold Snare Polypectomy Successfully Salvaged on Endoscopic Submucosal Dissection

Cold snare polypectomy is a well-established method for the resection of colorectal polyps measuring less than 10 mm in size. It may be performed in patients with early colorectal cancers because of the difficulty of endoscopic diagnosis. However, the therapeutic effect of cold snare polypectomy on cancers is unknown, and the need for appropriate surveillance and additional treatment for these patients remains to be fulfilled. Endoscopic submucosal dissection has been reported as a safe and effective method for treating recurrent or residual colorectal neoplasia following hot endoscopic mucosal resection. This report is of a case of a colorectal tumor measuring 8 mm that was treated using cold snare polypectomy and resulted in residual cancer. Endoscopic submucosal dissection was selected as salvage treatment for the residual lesion, and histopathological examination revealed free horizontal and vertical margins. We believe that performing endoscopic submucosal dissection at the site of the cancer resected with cold snare polypectomy ensured that there was no residual cancer left. It may be hypothesized that endoscopic submucosal dissection could evolve as the treatment of choice for patients with colorectal cancer after cold snare polypectomy.

Japan Gastroenterological Endoscopy Society guidelines for colorectal endoscopic submucosal dissection/endoscopic mucosal resection

Suitable lesions for endoscopic treatment include not only early colorectal carcinomas but also several types of precarcinomatous adenomas. It is important to establish practical guidelines wherein preoperative diagnosis of colorectal neoplasia and selection of endoscopic treatment procedures are appropriately outlined and to ensure that actual endoscopic treatment is useful and safe in general hospitals when carried out in accordance with guidelines. In cooperation with the Japanese Society for Cancer of the Colon and Rectum, the Japanese Society of Coloproctology, and the Japanese Society of Gastroenterology, the Japan Gastroenterological Endoscopy Society compiled colorectal endoscopic submucosal dissection/endoscopic mucosal resection guidelines by using evidence-based methods in 2014. The first edition of these guidelines was published 5 years ago. Accordingly, we have published the second edition of these guidelines based on recent new knowledge and evidence.

Current strategies for malignant pedunculated colorectal polyps

Despite significant advances in imaging techniques, the incidence of colorectal cancer has been increasing in recent years, with many cases still being diagnosed in advanced stages. Early detection and accurate staging remain the main factors that lead to a decrease in the cost and invasiveness of the curative techniques, significantly improving the outcome. However, the diagnosis of pedunculated early colorectal malignancy remains a current challenge. Data on the management of pedunculated cancer precursors, apart from data on nonpolypoid lesions, are still limited. An adequate technique for complete resection, which provides the best long-term outcome, is mandatory for curative intent. In this context, a discussion regarding the diagnosis of malignancy of pedunculated polyps, separate from non-pedunculated variants, is necessary. The purpose of this review is to provide a critical review of the most recent literature reporting the different features of malignant pedunculated colorectal polyps, including diagnosis and management strategies.

Predictive Factors for Lymph Node Metastasis in Submucosal Invasive Colorectal Carcinoma: A New Proposal of Depth of Invasion for Radical Surgery

BACKGROUND

Patients with lymph node metastasis (LNM) in submucosal invasive colorectal carcinoma (SM cancer) require additional surgical treatment after endoscopic dissection. However, because additional radical resection after endoscopic local resection may be unnecessary for cases without LNM, more specific criteria are required in order to diminish the incidence of further radical resection after endoscopic dissection.

METHODS

A total of 492 patients with biopsy-proven SM cancer who underwent curative surgery between January 2008 and December 2012 were collected and were divided into LNM group and no LNM group. The cutoff value for the depth of submucosal invasion was analyzed by a receiver operating characteristic (ROC) curve. In this retrospective study, the association between LNM and clinicopathologic factors was analyzed by logistic regression analysis.

RESULTS

The depth of submucosal invasion of 1900 μm was determined as the cutoff value by ROC curve. Significant, independent predictive factors for LNM included the depth of submucosal invasion >1900 μm (odds ratio [OR] 7.5; 95% confidence interval [CI] 3.1-18.3; p < 0.001), venous invasion (OR 2.4; 95% CI 1.1-5.5; p = 0.03), and poorly differentiated/mucinous adenocarcinoma (OR 6.3; 95% CI 1.3-30.8; p = 0.02).

CONCLUSIONS

Our study demonstrates that the depth of submucosal invasion (>1900 μm), vascular invasion and poorly differentiated/mucinous carcinoma were predictive factors of LNM in patients with SM cancer. These predictors may help to reduce the incidence of unnecessary surgery after endoscopic resection.

Expression of matrix metalloproteinase-7 correlates with the invasion of T1 colorectal carcinoma

T1 colorectal carcinomas (CRCs) are an initial site of metastatic spread. Various risk factors for lymph node metastasis have been investigated in T1 CRCs. However, the major step in the entire process of metastasis remains unclear. In terms of carcinoma invasion and metastasis, matrix metalloproteinases (MMPs) have recently gained increasing attention. Notably, MMP-7 is frequently overexpressed in CRCs, but its implication has not been determined in T1 CRCs yet. The present study aimed to clarify the associations between the pathological risk factors of T1 CRCs and MMP-7. In the current study, 211 lesions of T1 CRC that were resected endoscopically or surgically at Showa University Northern Yokohama Hospital (Yokohama, Japan) between April 2008 and December 2009 were retrospectively analyzed. MMP-7 was immunostained and evaluated by its frequency of expression. Pathological factors of T1 CRCs were analyzed in association with MMP-7 expression. Furthermore, the ultrastructural alterations of carcinoma invasion were examined using low vacuum-scanning electron microscopy (LV-SEM). MMP-7 expression was associated with venous invasion (P=0.005), and LV-SEM revealed the disappearance of the normal structure of collagen and elastic fibers of veins invaded by tumor cells expressing MMP-7. At the invasive front, MMP-7 has a vital role in carcinoma invasion, correlating with venous invasion of T1 CRCs.

Colorectal endoscopic mucosal resection (EMR)

Colonoscopy has the benefit of detecting and treating precancerous adenomatous polyps and thus reduces mortality associated with CRC. Screening colonoscopy is the keystone for prevention of colorectal cancer. Over the last 20 years there has been increased in the management of large colorectal polyps from surgery to endoscopic removal techniques which is less invasive. Traditionally surgical resection was the treatment of choice for many years for larger polyps but colectomy poses significant morbidity of 14-46% and mortality of up to 7%. There are several advantages of endoscopic resection technique over surgery; it is less invasive, less expensive, has rapid recovery, and preserves the normal gut functions. In addition patient satisfaction and efficacy of EMR is higher with minor complications. Thus, this has facilitated the development of advanced resection technique for the treatment of large colorectal polyps called as endoscopic mucosal resection (EMR).

Management and risk factor of stenosis after endoscopic submucosal dissection for colorectal neoplasms

BACKGROUND AND AIM

Although endoscopic submucosal dissection (ESD) enables en bloc removal of large colorectal neoplasms, the incidence of stenosis after ESD and its risk factors have not been well described. This study aimed to determine the risk factors of stenosis and verify the surveillance and treatment of stenosis.

METHODS

This retrospective study included 822 patients, with a total of 912 consecutive colorectal lesions, who underwent ESD from September 2003 to May 2015. The main outcome measures were incidence of stenosis and its relationship with the clinicopathologic factors in surveillance.

RESULTS

Surveillance endoscopy was performed 6 months after ESD. Four of the 822 patients (0.49%) developed stenosis and required unanticipated endoscopy. The other 908 cases in 818 patients showed no symptoms or only slight abdominal discomfort (that was controlled with medication) and did not require any dilation or steroid therapies. Post-ESD stenosis was observed in 11.1% (2/18) of patients with circumferential resection between ≥90% and <100% and in 50% (2/4) of patients with circumferential resection of 100%. Among the 50 cases with a circumferential mucosal defect ≥75%, a circumferential mucosal defect ≥90% was a significant risk factor (P = .005). Four patients with stenosis were treated successfully by endoscopic dilation.

CONCLUSIONS

Circumferential mucosal defect of more than 90% is a significant risk factor for stenosis after colorectal ESD. Surveillance endoscopy 6 months after ESD is recommended to assess for development of stenosis. Defects smaller than 90% do not require close endoscopic follow-up or prophylactic measures for prevention of post-ESD stenosis. (UMIN clinical trial registration number: UMIN000015754.).

Can positron emission tomography detect colorectal adenomas and cancers?

BACKGROUND AND AIM

Fluorine-18 2-fluoro-2-deoxy-d-glucose positron emission tomography (PET) is effective and less invasive than other modalities used to diagnose tumors, including colorectal cancer (CRC). However, the detectability of adenomas and CRCs, especially in the early stages, is unclear.

METHODS

We evaluated the records of 2323 consecutive eligible patients who underwent both a total colonoscopy (TCS) and PET between October 2002 and September 2012 at a tertiary cancer center. The PET findings were verified by TCS performed independently within 1 year. Target lesions were defined as CRCs and adenomas that were 6 mm or larger in size.

RESULTS

Total colonoscopy detected 532 target lesions ≥ 6 mm in size: 56 T2-T4 CRCs, 39 T1 CRCs, 223 advanced adenomas, and 214 low-grade adenomas. Of the 532 lesions, 216 (40.6%) were PET positive. Of the 369 cases with positive uptakes, PET detected target lesions in the matched segments for 58.5% (216/369). Sensitivity of PET to T2-T4 CRCs, T1 CRCs, advanced adenomas, and low-grade adenomas was 92.9%, 79.5%, 50.7%, and 9.3%, respectively. PET could detect 76.5% (13/17) of T1 CRCs whose size is 10 to 19 mm and 85.0% (17/20) of T1 CRCs equal or larger than 20 mm. The multivariate analysis excluding T2-T4 CRCs showed malignant histology, larger size, protruded lesions, villous histology, and lesions in distal colon were significant factors.

CONCLUSIONS

Sensitivity of PET for detecting T2-T4 and even T1 cancers are promising. However, sensitivity of PET to adenomas, even advanced adenomas, is limited.

Colonic Polyps: Treatment

Colonic polyps are considered to be precursors of colon cancer based on several different molecular pathway models and should be resected with a principle of complete excisional biopsy. Several techniques are available for excisional biopsy, ranging from endoscopic techniques such as snare polypectomy, endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD) to surgical colonic resection and colonic endolaparoscopic surgery (CELS). This article focuses on these modalities with contemporary recommendations for choice of modality based on the size and features of the polyp encountered upon endoscopy. In addition, the morphologically apparent risk factors for polyps harboring invasive malignancy are discussed along with implications for management. Current literature on the comparative risks and benefits of EMR, ESD, CELS, and surgical resection is reviewed, as well as recommendations regarding cancer risk and subsequent surveillance.

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.

A four-dimensional snapshot hyperspectral video-endoscope for bio-imaging applications

Hyperspectral imaging has proven significance in bio-imaging applications and it has the ability to capture up to several hundred images of different wavelengths offering relevant spectral signatures. To use hyperspectral imaging for in vivo monitoring and diagnosis of the internal body cavities, a snapshot hyperspectral video-endoscope is required. However, such reported systems provide only about 50 wavelengths. We have developed a four-dimensional snapshot hyperspectral video-endoscope with a spectral range of 400–1000 nm, which can detect 756 wavelengths for imaging, significantly more than such systems. Capturing the three-dimensional datacube sequentially gives the fourth dimension. All these are achieved through a flexible two-dimensional to one-dimensional fiber bundle. The potential of this custom designed and fabricated compact biomedical probe is demonstrated by imaging phantom tissue samples in reflectance and fluorescence imaging modalities. It is envisaged that this novel concept and developed probe will contribute significantly towards diagnostic in vivo biomedical imaging in the near future.

Management of colorectal T1 carcinoma treated by endoscopic resection from the Western perspective

Detection of early colorectal cancer is expected to rise in light of national colorectal cancer screening programs. This The present review article delineates current endoscopic risk assessments, differentiating invasive from non-invasive neoplasia, for high likelihood of lymph node metastasis in early colorectal cancer, also termed high-risk early colorectal cancer, and endoscopic and surgical resection methods from a Western hemisphere perspective.

Practical problems of measuring depth of submucosal invasion in T1 colorectal carcinomas

PURPOSE

Submucosal invasion depth (SID) in colorectal carcinoma (CRC) is an important factor in estimating risk of lymph node metastasis, but can be difficult to measure, leading to inadequate or over-extensive treatment. Here, we aimed to clarify the practical aspects of measuring SID in T1 CRC.

METHODS

We investigated 568 T1 CRCs that were resected surgically at our hospital from April 2001 to December 2013, and relationships between SID and clinicopathological factors, including the means of measurement, lesion morphology, and lymph node metastasis.

RESULTS

Of these 568 lesions, the SID was ≥1000 μm in 508 lesions. SIDs for lesions measured from the surface layer were all ≥1000 μm. Although lesions with SIDs ≥1000 μm were associated with significantly higher levels of unfavorable histologic types and lymphovascular infiltration than shallower lesions, a depth of ≥1000 μm was not a significant risk factor for lymph node metastasis (LNM) (6.7 vs. 9.8 %; P = 0.64), and no lesions for which the sole pathological factor was SID ≥1000 μm had lymph node metastasis. Protruded lesions showed deeper SIDs than other types.

CONCLUSIONS

Although we found several problems of measuring SID in this study, we also found, surprisingly, that SID is not a risk factor for lymph node metastasis, and its measurement is not needed to estimate the risk of lymph node metastasis.

Optimal use of colonoscopy and fecal immunochemical test for population-based colorectal cancer screening: a cost-effectiveness analysis using Japanese data

OBJECTIVE

There have been few cost-effectiveness analyses of population-based colorectal cancer screening in Japan, and there is no consensus on the optimal use of total colonoscopy and the fecal immunochemical test for colorectal cancer screening with regard to cost-effectiveness and total colonoscopy workload. The present study aimed to examine the cost-effectiveness of colorectal cancer screening using Japanese data to identify the optimal use of total colonoscopy and fecal immunochemical test.

METHODS

We developed a Markov model to assess the cost-effectiveness of colorectal cancer screening offered to an average-risk population aged 40 years or over. The cost, quality-adjusted life-years and number of total colonoscopy procedures required were evaluated for three screening strategies: (i) a fecal immunochemical test-based strategy; (ii) a total colonoscopy-based strategy; (iii) a strategy of adding population-wide total colonoscopy at 50 years to a fecal immunochemical test-based strategy.

RESULTS

All three strategies dominated no screening. Among the three, Strategy 1 was dominated by Strategy 3, and the incremental cost per quality-adjusted life-years gained for Strategy 2 against Strategies 1 and 3 were JPY 293 616 and JPY 781 342, respectively. Within the Japanese threshold (JPY 5-6 million per QALY gained), Strategy 2 was the most cost-effective, followed by Strategy 3; however, Strategy 2 required more than double the number of total colonoscopy procedures than the other strategies.

CONCLUSIONS

The total colonoscopy-based strategy could be the most cost-effective for population-based colorectal cancer screening in Japan. However, it requires more total colonoscopy procedures than the other strategies. Depending on total colonoscopy capacity, the strategy of adding total colonoscopy for individuals at a specified age to a fecal immunochemical test-based screening may be an optimal solution.

Characteristics of colorectal tumours in asymptomatic patients with negative immunochemical faecal occult blood test results

The immunochemical faecal occult blood test (iFOBT) is a simple, non-invasive colorectal cancer (CRC) screening method for reducing CRC-related mortality. However, the sensitivity of iFOBT is imperfect and certain colonic neoplasms that require removal may be missed. The aim of this study was to investigate the incidence and characteristics of CRC in asymptomatic, iFOBT-negative patients who underwent opportunistic screening. A total of 919 subclinical patients (276 iFOBT-positive and 643 iFOBT-negative) in the health screening program of our hospital underwent total colonoscopy (TCS) within 2 years after iFOBT. The patients were divided into an iFOBT-positive and an iFOBT-negative group and the TCS findings were compared between the two groups. Although the incidence of advanced neoplasia (CRC, high-grade dysplasia, adenoma sized ≥10 mm and tubulovillous adenoma) was significantly higher in the iFOBT-positive group, these lesions were also found in 6.3% of iFOBT-negative patients. The lesions tended to be proximally located and non-protruding. In conclusion, screening with iFOBT remains clinically significant. However, colonoscopy is indispensable for reducing the incidence and mortality of CRC.

Usefulness of a novel calibrated hood to determine indications for colon polypectomy: visual estimation of polyp size is not accurate

PURPOSE

Accurate measurement of polyp size during colonoscopy is important because the size is a surrogate marker of cancer, but a standardized measurement technique to measure polyp size has yet to be determined. We have developed a new device "a novel calibrated hood." We assessed polyp size by visual estimation and measurement using the calibrated hood.

METHODS

Patients who underwent polypectomy from November 2012 to September 2013 and who had received screening colonoscopy within 6 months prior to the polypectomy were included in this study. Polypectomy was performed attaching the calibrated hood. The endoscopist measured the polyp size using the calibrated hood. Polyp size was compared between visual estimation and measurement using the calibrated hood.

RESULTS

Seventy-five patients with 157 polyps were included. Seventy-seven polyps fulfilled the selection criteria. Mean polyp size by visual estimation was 6.57 ± 2.15, and by using calibrated hood was 5.94 ± 1.73 (p = 0.005). There was a significant difference between measurements using the calibrated hood vs. visual estimation by inexperienced trainees; however, there was no difference in case of well-experienced endoscopists. By visual estimation, 11 of 19 polyps were decided for ≥5 mm despite being less than 5 mm, and 5 of 58 polyps were decided for <5 mm despite being 5 mm or larger in diameter.

CONCLUSION

Visual estimation of polyp size is not accurate. It is important to measure the size by an objective way, and the calibrated hood is useful in measuring polyp size, from the standpoint of accurately determining indication for polypectomy.

A clinical model for predicting lymph node metastasis in submucosal invasive (T1) colorectal cancer

BACKGROUND

No single histopathological feature of submucosal invasive colorectal cancer (T1-CRC) can reliably predict the risk for lymph node metastasis (LNM).

AIM

The purpose of the study was to develop a prediction model of LNM in T1-CRC.

METHODS

Ninety-seven surgically resected T1-CRC at our institution were retrospectively evaluated. Morphology, localization, grading, mode of growth, presence of background adenoma, lymphoid infiltration, angiolymphatic invasion, budding, and depth of invasion were assessed. Mortality and morbidity related to surgery were also evaluated. Benefit-risk balance was assessed according to the presence of severe complications and to the presence of LNM.

RESULTS

Fourteen cases had LNM (14%). Eight patients (8%) presented severe surgical complications and there were two deaths (2 %). Infiltrative growth pattern (OR 31.91, 95% CI 2.37-428.36; p = 0.009) and the absence of lymphoid infiltrate (OR 28.75; 95% CI 2.13-388.37; p = 0.011) were the only variables independently associated with LNM in the multivariate analysis. Both variables were included in the prediction model together with sessile morphology (OR 4.88; 95% CI 0.81-29.3; p = 0.083) and poorly differentiated carcinoma (OR 11.77; 95% CI 0.77-179.83; p = 0.076). A 0-100 score was developed (infiltrative growth pattern: no = 0, yes = 33; lymphoid infiltrate: no = 29, yes = 0; sessile morphology: no = 0, yes = 15; poorly differentiated: no = 0, yes = 23). Cutoff point to indicate additional surgery was set in 35 points (i.e., 10% risk LNM). Discrimination of the prediction model was excellent (AUC 0.90; 95% CI 0.81-0.99).

CONCLUSION

Combined evaluation of infiltrative growth pattern, lymphoid infiltration, poorly differentiated carcinoma, and sessile appearance showed good performance for discriminating T1-CRC patients with LNM. The benefit-risk balance was in favor of surgery when at least two of these criteria were present.

JGES guidelines for colorectal endoscopic submucosal dissection/endoscopic mucosal resection

Colorectal endoscopic submucosal dissection (ESD) has become common in recent years. Suitable lesions for endoscopic treatment include not only early colorectal carcinomas but also many types of precarcinomatous adenomas. It is important to establish practical guidelines in which the preoperative diagnosis of colorectal neoplasia and the selection of endoscopic treatment procedures are properly outlined, and to ensure that the actual endoscopic treatment is useful and safe in general hospitals when carried out in accordance with the guidelines. In cooperation with the Japanese Society for Cancer of the Colon and Rectum, the Japanese Society of Coloproctology, and the Japanese Society of Gastroenterology, the Japan Gastroenterological Endoscopy Society has recently compiled a set of colorectal ESD/endoscopic mucosal resection (EMR) guidelines using evidence-based methods. The guidelines focus on the diagnostic and therapeutic strategies and caveat before, during, and after ESD/EMR and, in this regard, exclude the specific procedures, types and proper use of instruments, devices, and drugs. Although eight areas, ranging from indication to pathology, were originally planned for inclusion in these guidelines, evidence was scarce in each area. Therefore, grades of recommendation were determined largely through expert consensus in these areas.

[Prognostic values of the clinical, morphological and molecular biological characteristics of colon adenocarcinoma]

OBJECTIVE

to estimate the predictive and prognostic factors using morphological studies in patients with colon cancer to increase survival rates.

SUBJECTS AND METHODS

Immunohistochemical examination was made in 582 patients with colon adenocarcinoma, by determining 11 different indicators relating to the development of the tumor and its treatment.

RESULTS

The simultaneous determination of the chemokine receptor CXCR4 and proliferative activity (Ki-67 expression) can define disease prognosis in view of relapse-survival rates in patients with Stage II colon cancer after radical surgical treatment.

CONCLUSION

Thymidylate synthase and thymidine phosphorylase are of predictive value. The immunohistochemical examination of other markers, such as ALDH1, CCR10, ERCC-1, DYPD, topoisomerase II alpha, and class III beta-tubulin for the choice of treatment policy for patients with colon cancer has indicated that they are of no value.

Consensus on the Prevention, Screening, Early Diagnosis and Treatment of Colorectal Tumors in China: Chinese Society of Gastroenterology, October 14-15, 2011, Shanghai, China

BACKGROUND

Colorectal cancer (CRC) is steadily increasing in China. Colorectal adenoma (CRA) is the most important precancerous disease of CRC. Screening for colorectal tumors can aid early diagnosis. Advances in endoscopic mucosal resection and endoscopic submucosal dissection can aid the early treatment of colorectal tumors. Furthermore, because of high risk of recurrence after removal of adenomas under endoscopy, factors contributing to recurrence, the follow-up mode and the interval established, and the feasibility of application and the time of various chemical preventions should be concerned. However, a relevant consensus on the screening, early diagnosis and treatment, and prevention of colorectal tumors in China is lacking.

SUMMARY

The consensus recommendations include epidemiology, pathology, screening, early diagnosis, endoscopic treatment, monitoring and follow-up, and chemoprevention of colorectal tumors in China.

KEY MESSAGE

This is the first consensus on the prevention, screening, early diagnosis and treatment of CRA and CRC in China based on evidence in the literature and on local data.

PRACTICAL IMPLICATIONS

Through reviewing the literature, regional data and passing the consensus by an anonymous vote, gastroenterology experts from all over China launch the consensus recommendations in Shanghai. The incidence and mortality of CRC in China has increased, and the incidence or detection rate of CRA has increased rapidly. Screening for colorectal tumors should be performed at age 50-74 years. Preliminary screening should be undertaken to find persons at high risk, followed by colonoscopy. A screening cycle of 3 years is recommended for persistent interventions. Opportunistic screening is a mode suitable for the current healthcare system and national situation. Colonoscopy combined with pathological examination is the standard method for the diagnosis of colorectal tumors. CRA removal under endoscopy can prevent CRC to some extent, but CRA has an obvious recurrence trend. The follow-up interval after the removal or surgery of colorectal tumors should be different with lesions. Primary prevention of CRA includes improved diet with more fiber, supplements containing calcium and vitamin D, supplements containing folic acid for those with low hemoglobin levels, and cessation of tobacco smoking. Non-steroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors have been recognized to prevent recurrence after adenoma removal.

Efficiency of endocytoscopy in differentiating types of serrated polyps

BACKGROUND

Accurate endoscopic criteria are needed to differentiate serrated polyps, including hyperplastic polyp (HP), sessile serrated adenoma/polyp (SSA/P), and traditional serrated adenoma (TSA), because some are precursors of colorectal cancers.

OBJECTIVE

To determine the endocytoscopic features of each type of serrated polyp, especially the shapes of lumens and nuclei.

DESIGN

Retrospective study.

SETTING

Single, tertiary-care referral center.

PATIENTS

Patients who underwent removal of serrated polyps from May 2005 to December 2012.

INTERVENTION

Endocytoscopy was performed. Endocytoscopic images were evaluated by assessing the shapes of the lumens and nuclei of the target lesions.

MAIN OUTCOME MEASUREMENTS

The significant endocytoscopic features in differentiating among types of serrated polyps.

RESULTS

Of the 58 eligible lesions, 27 were classified as HP, 12 as SSA/P, and 19 as TSA. Most HPs (77.8%) had star-like lumens, and most SSA/Ps (83.3%) had oval lumens. The lumens of TSAs were serrated (31.6%) or villous (68.4%), with both shapes seen only in TSAs. Most HPs (92.6%) and SSA/Ps (75.0%) had small, round nuclei, and all TSAs had fusiform nuclei. Features significantly differentiating TSAs from HPs and SSA/Ps were the presence of fusiform nuclei (P < .001) and villous (P < .001) and serrated (P = .002) lumens. The presence of oval lumens was significantly characteristic of SSA/Ps (P < .001), and the presence of star-like lumens was significantly characteristic of HPs (P < .001).

LIMITATIONS

Retrospective design. Single-center study.

CONCLUSION

The shape of lumens and nuclei on endocytoscopy can efficiently differentiate among the different types of serrated polyps. (

CLINICAL TRIAL REGISTRATION NUMBER

UMIN Clinical Trials Registry UMIN000007850.).

Improved real-time rt-PCR assays of two colorectal cancer peripheral blood mRNA biomarkers: a pilot study

BACKGROUND

Efficient screening for detection of colorectal cancer (CRC) at earlier stages reduces its mortality. The purpose of this study was to investigate expression of carcinoembryonic antigen (CEA) and human telomerase reverse transcriptase (hTERT) mRNA in peripheral blood of CRC patients and to present strategies for early detection screen test.

METHODS

Twenty seven patients in non-metastatic stage and 27 healthy individuals were studied. Expression of CEA, hTERT mRNA and 18srRNA (18s subunit of ribosomal RNA, as reference gene) were determined based on real-time RT-PCR on 3 µg of total RNA from blood in 3 separate vials (1 µg per vial).

RESULTS

Positive expression rate of CEA mRNA (78%) and hTERT mRNA (81%) were higher in patient group (P<0.001). These rates were meaningfully higher than the results of individual vials containing only 1 µg of total RNA. Difference between Ct values of markers with 18srRNA ΔCt) was higher in healthy group than patient one. Therefore, a ΔCt cut-off value was determined for distinguishing between true- and false-positive results. Concurrent expression of both markers was found in 67% of the patients, which was higher than healthy cases (11%). Combination of concurrent marker expression with cut-off point strategy increased specificity to 100%.

CONCLUSION

These results showed that concurrent evaluation of marker expression and performing the test on 3 µg of samples in 3 separate vials may increase specificity and sensitivity of real-time RT-PCR for early detection of non-metastatic CRC. However, more investigations with larger numbers of samples are needed to verify these results.

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.

The efficacy and safety of prophylactic closure for a large mucosal defect after colorectal endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is not a common treatment for colorectal neoplasms because of its technical difficulties and has a higher incidence of complication. In particular, perforation is one of the severe complications and these patients require surgical intervention. However, whether prophylactic closure after colorectal ESD prevents perforation and other complications is not known. In the present study, we assessed the efficacy and safety of prophylactic closure for a large mucosal defect after colorectal ESD using a conventional clip and over-the-scope clip (OTSC) system. From April 2010 to December 2012, 68 patients with colorectal tumors were treated with ESD. The prohylactic closure was indicated for patients with excessive coagulation in the muscularis propria or larger resection size. The closure group reduced the peritoneal inflammatory reaction and abdominal symptoms without increasing complications. The closure group also had a significantly lower WBC count (post operative day 1), CRP (post operative day 4) and abdominal pain after colorectal ESD compared to the non-closure group. Perforation occurred in 1 case, and postoperative bleeding in 2 cases, with only 1 bleeding case needing an emergency endoscopy in the non-closure group. One perforation case needed emergency surgery because the endoscopic treatment was ineffective. Without increasing adverse effects, the prophylactic closure efficiently reduced the inflammatory reaction and abdominal symptoms of colorectal ESD in patients with large superficial colorectal neoplasms.

Diagnostic accuracy and interobserver agreement in predicting the submucosal invasion of colorectal tumors using gross findings, pit patterns, and microvasculatures

Background/Aims

Depth of invasion is one of the most important factors for establishing treatment strategy for colorectal tumors.

Methods

Three blinded experts reviewed electronic photos and video clips of 33 early colorectal cancer-like lesions. They estimated the depth of invasion based on conventional white light endoscopy (CWE), magnifying chromoendoscopy (MCE), and magnifying narrow band imaging endoscopy (MNE).

Results

The lesions included nine mucosal low-grade neoplasias, 16 mucosal high grade neoplasias, and eight carcinomas with invasion to the submucosal layer or beyond. The diagnostic accuracy for submucosal invasion by CWE ranged from 67% to 82%, while those by MCE and MNE ranged from 85% to 88% and 85% to 88%, respectively. The diagnostic accuracy significantly differed between CWE and MCE (p=0.034) and between CWE and MNE (p=0.039). The kappa values for CWE, MCE, and MNE among the endoscopists were 0.564, 0.673, and 0.673, respectively.

Conclusions

The estimation of submucosal invasion for early colorectal cancer-like lesions based on MCE or MNE is more accurate than CWE. MCE and MNE were demonstrated to have substantial agreement for predicting submucosal invasion.

Clinicopathological differences of colorectal cancers according to tumor origin: Identification of possibly de novo lesions

Colorectal cancer (CRC) is considered to develop through the conventional adenoma-carcinoma sequence. However, the existence of de novo carcinogenesis, without any intervening precursor lesions, has been suggested for certain morphologically different tumors lacking polypoid characteristics. The presence of such tumors, along with their correlation with cardinal clinicopathological parameters, such as stage, grade and site, was retrospectively investigated in a series of 119 surgically treated CRC cases. The absence of particular polypoid characteristics (adenomatous remnants or coexisting polyps in the tumor vicinity) in combination with an infiltrative (or ulceroinfiltrative) growth pattern, were the criteria defining the nonpolypoid origin. The recorded frequencies of remnants, coexisting polyps and infiltrative tumors were 7, 5, 9 and 32%, respectively. The incidence of cases meeting the above-mentioned criteria was 28.5%. These nonpolypoid lesions exhibited a predilection for proximal anatomical site (P=0.04), probably associated with their infiltrative pattern. Most importantly, de novo lesions (unlike polypoid) were rarely found among cases with indolent tumor characteristics (stage I or grade I, P=0.008), showing a considerably different overall pattern of distribution by stage and grade as compared to that of polypoid tumors (P=0.03). The fact that nonpolypoid CRCs appeared to be clinicopathologically different from their polypoid counterparts is supportive of possible de novo origin and suggestive of a likely worse clinical behavior. The impact of these findings should be investigated to determine potential applications in the diagnosis, treatment and surveillance of these lesions.

Endoscopic submucosal dissection for large laterally spreading tumors involving the ileocecal valve and terminal ileum

Endoscopic submucosal dissection is a challenging technique that enables en-bloc resection for large colorectal tumors, as laterally spreading tumors, particularly difficult, if the ileocecal valve and terminal ileum is involved. Herein, we report on one of 4 cases. The procedures, using a bipolar needle knife (B-Knife) to reduce the perforation risk and carbon dioxide instead of conventional air insufflation for patient comfort, achieved curative resections without any complications.

Diagnostic performance of chromoendoscopy and narrow band imaging for colonic neoplasms: a meta-analysis

AIM

We conducted a meta-analysis to compare the diagnostic test performance of chromoendoscopy and narrow band imaging (NBI) for colonic neoplasms.

METHOD

MEDLINE, EMBASE and the Cochrane Library were searched (1966 to March 2009). Articles were included if: (i) chromoendoscopy or NBI was used, (ii) sensitivity and specificity were reported; (iii) absolute numbers of true-positive, false-positive, true-negative and false-negative results were provided or could be calculated; and (iv) pathology was used as the reference standard. Sensitivity and specificity were pooled using random effects model. Secondary analyses were conducted by limiting the studies in which magnifying endoscopy was used alone as a diagnostic modality, and polyp size and macroscopic appearance of lesions were not considered.

RESULTS

Of 1342 screened articles, 27 met the inclusion criteria. Pooled sensitivity for chromoendoscopy and NBI was 0.94 (95% CI, 0.92-0.95) and 0.94 (0.91-0.97), and specificity was 0.82 (0.77-0.88) and 0.86 (0.83-0.89), respectively. There were no differences in sensitivity (P = 0.99) or specificity (P = 0.54) between the two methods. In the secondary analysis, pooled sensitivity for choromoendoscopy and NBI was 0.93 (95% CI, 0.90-0.97) and 0.96 (0.93-0.99) and specificity was 0.80 (0.73-0.87) and 0.85 (0.78-0.92). respectively. Overall, the pooled false-negative rate was 0.057 (95% CI, 0.040-0.73) for chromoendoscopy and 0.057 (95% CI, 0.028-0.085) for NBI.

CONCLUSION

Chromoendoscopy and NBI had similar diagnostic test characteristics in the assessment of colonic neoplasms; however, the false-negative rate for both methods of 5.7% is an unacceptably high rate and currently therefore, neither method is ready for general use.

Clinical usefulness of pit patterns for detecting colonic lesions requiring surgical treatment

BACKGROUND

The number of patients suffering from colorectal cancer is increasing. According to Japanese guidelines, lesions with a submucosal invasive depth >1,000 μm should be treated with radical proctocolectomy. We propose and evaluate a new clinical classification for pit patterns that uses endoscopy to assess lesion depth for determination of the appropriate therapeutic approach for early colorectal cancers and adenomas.

METHODS

Endoscopic images of colorectal adenomas and early cancer cases with type V(I) pit pattern, resected surgically or endoscopically from April 2002 to April 2007 at Showa University Yokohama Northern Hospital, were utilized for analysis. Each image was retrospectively analyzed for (A) pit narrowness, (B) irregular pit margins, and (C) indistinct stromal staining. Sensitivity, specificity, and predictive value were evaluated as major outcomes, using pathological results as the standard.

RESULT

In total, 186 cases were assessed. With all features considered (A, B, and C), the sensitivity, specificity, and positive and negative predictive values were 47.8%, 86.3%, 66.0%, and 74.2%, respectively. When limited to two features (A and B), these values were 75.3%, 81.2%, 70.2%, and 84.8%, respectively.

CONCLUSION

Our results suggest that the established criteria can, to a certain degree, distinguish between high and low irregularity in colorectal lesions with V(I) pit pattern indicating submucosal cancer infiltration of more or less than 1,000 μm with the clinical consequence of surgery versus endoscopic mucosal resection/endoscopic mucosal dissection.

Colorectal carcinogenesis: Review of human and experimental animal studies

This review gives a comprehensive overview of cancer development and links it to the current understanding of tumorigenesis and malignant progression in colorectal cancer. The focus is on human and murine colorectal carcinogenesis and the histogenesis of this malignant disorder. A summary of a model of colitis-associated colon tumorigenesis (an AOM/DSS model) will also be presented. The earliest phases of colorectal oncogenesis occur in the normal mucosa, with a disorder of cell replication. The large majority of colorectal malignancies develop from an adenomatous polyp (adenoma). These can be defined as well-demarcated masses of epithelial dysplasia, with uncontrolled crypt cell proliferation. When neoplastic cells pass through the muscularis mucosa and infiltrate the submucosa, they are malignant. Carcinomas usually originate from pre-existing adenomas, but this does not imply that all polyps undergo malignant changes and does not exclude de novo oncogenesis. Besides adenomas, there are other types of pre-neoplasia, which include hyperplastic polyps, serrated adenomas, flat adenomas and dysplasia that occurs in the inflamed colon in associated with inflammatory bowel disease. Colorectal neoplasms cover a wide range of pre-malignant and malignant lesions, many of which can easily be removed during endoscopy if they are small. Colorectal neoplasms and/or pre-neoplasms can be prevented by interfering with the various steps of oncogenesis, which begins with uncontrolled epithelial cell replication, continues with the formation of adenomas and eventually evolves into malignancy. The knowledge described herein will help to reduce and prevent this malignancy, which is one of the most frequent neoplasms in some Western and developed countries.

Essence of affinity and specificity of peanut agglutinin-immobilized fluorescent nanospheres with surface poly(N-vinylacetamide) chains for colorectal cancer

We have designed a novel colonoscopic imaging agent that is composed of submicron-sized fluorescent polystyrene nanospheres with two functional groups - peanut agglutinin (PNA) and poly(N-vinylaceamide) (PNVA) - on their surfaces. PNA is a targeting moiety that binds to β-d-galactosyl-(1-3)-N-acetyl-d-galactosamine (Gal-β(1-3)GalNAc), which is the terminal sugar of the Thomsen-Friedenreich antigen that is specifically expressed on the mucosal side of colorectal cancer cells; it is anchored on the nanosphere surface via a poly(methacrylic) acid (PMAA) linker. PNVA is immobilized to enhance the specificity of PNA by reducing nonspecific interactions between the imaging agent and normal tissues. The essential nature of both functional groups was evaluated through in vivo experiments using PNA-free and PNVA-free nanospheres. The imaging agent recognized specifically tumors on the cecal mucosa of immune-deficient mice in which human colorectal cancer cells had been implanted; however, the recognition capability disappeared when PNA was replaced with wheat germ agglutinin, which has no affinity for Gal-β(1-3)GalNAc. PNA-free nanospheres with exclusively surface PNVA chains rarely adhered to the cecal mucosa of normal mice that did not undergo the cancer cell implantation. In contrast, there were strong nonspecific interactions between normal tissues and PNA-free nanospheres with exclusively surface PMAA chains. In vivo data proved that PNA and PNVA were essential for biorecognition for tumor tissues and a reduction of nonspecific interactions with normal tissues, respectively.

On-the-fly detection of changes on and below the surface in epithelium mucosal tissue architecture from scattered light

In this paper we present a technique to raise a flag on the fly when a transition occurs between different mucosal architectures on or below the surface. The segmentation is based on a novel difference metric for detecting an abrupt change in the parameters extracted from a Stochastic Decomposition Method (SDM) that models the scattered light reflected from the mucosal tissue structure over an area (2-D scan) illuminated by an optical sensor (fiber) emitting light at either one wavelength or with white light. This work has the potential to enhance the endoscopist's ability to locate and identify abnormal mucosal architectures in particular when the disease is developing below the surface and hence becoming hidden during colonoscopy or endoscopic examination. It also has also potential in helping deciding as to when and where to take biopsies; steps that should lead to improvement in the diagnostic yield.

A potential of peanut agglutinin-immobilized fluorescent nanospheres as a safe candidate of diagnostic drugs for colonoscopy

We designed peanut agglutinin (PNA)-immobilized fluorescent nanospheres as a non-absorbable endoscopic imaging agent capable of being administered intracolonically. Following our previous researches with evidence that the imaging agent recognized small-sized colorectal tumors on the mucosal surface with high affinity and specificity in animal experiments, a potential of this nanoprobe as a drug candidate was evaluated from a safety perspective. The imaging agent detects colorectal tumors through recognition of the tumor-specific antigen by PNA immobilized on the nanosphere surface, and the detection is made via the fluorescent signal derived from coumarin 6 encapsulated into the nanosphere core. The stability studies revealed that the high activity of PNA was maintained and there was no significant leakage of coumarin 6 after intracolonic administration of the imaging agent. Cytotoxicity studies indicated that no local damage to the large intestinal membrane was induced by the imaging agent. Further, in vitro and in vivo permeation studies demonstrated that there was no significant permeation of the imaging agent through the monolayer of cultured cells and that the imaging agent administered locally to the luminal side of the large intestine was almost completely recovered from the administration site. Therefore, we concluded that the imaging agent is a safe and stable probe which remains in the large intestine without systemic exposure.

Present status and perspectives of colorectal cancer in Asia: Colorectal Cancer Working Group report in 30th Asia-Pacific Cancer Conference

OBJECTIVE

To reveal the present status and future directions of colorectal cancer in Asia.

METHODS

The Working Group consisted of oncologists from six Asian countries (Japan, Korea, Hong Kong, China, Taiwan, Singapore and Philippines) discussed colorectal cancer in the 30th Asia-Pacific Cancer Conference and made a consensus report.

RESULTS

The incidence of colorectal cancer has been increasing rapidly in recent decades, and mortality has also increased except in Japan and Singapore. Colorectal screening with fecal occult blood tests is a national policy in Taiwan, Japan and Korea. Total colonoscopy is the most common examination for diagnosing colorectal cancers and neoplasms. However, there are differences in the macroscopic classification used. Laparoscopic surgery for colon cancer is extensively used, although the indication varies. Adequate lymph node harvesting of more than 12 nodes is performed in most countries. Neoadjuvant chemoradiation therapy is not routinely done for T2 or T3 rectal cancer. Total mesorectal excision is the standard surgery for rectal cancer. Survival rate data are unavailable for many countries and should be compiled in all. The differences in the health-care delivery systems affect the treatment choices for unresectable colorectal cancer. Infusional 5-FU plus leucovorin plus oxaliplatin (FOLFOX) is the most popular first-line regimen. Cetuximab is mainly used as a second- or third-line regimen with reference to k-ras mutation. Oxaliplatin-based adjuvant chemotherapy is commonly used for stage III disease, whereas the clinical practice for stage II disease varies.

CONCLUSIONS

Further clinical cooperation is needed to optimize the management of colorectal cancer in Asia.

Safe procedure in endoscopic submucosal dissection for colorectal tumors focused on preventing complications

Endoscopic submucosal dissection (ESD) is efficient for en bloc resection of large colorectal tumors. However, it has several technical difficulties, because the wall of the colon is thin and due to the winding nature of the colon. The main complications of ESD comprise postoperative perforation and hemorrhage, similar to endoscopic mucosal resection (EMR). In particular, the rate of perforation in ESD is higher than that in EMR. Perforation of the colon can cause fatal peritonitis. Endoscopic clipping is reported to be an efficient therapy for perforation. Most cases with perforation are treated conservatively without urgent surgical intervention. However, the rate of postoperative hemorrhage in ESD is similar to that in EMR. Endoscopic therapy including endoscopic clipping is performed and most of the cases are treated conservatively without blood transfusion. In blood examination, some degree of inflammation is detected after ESD. For the standardization of ESD, it is most important to decrease the rate of perforation. Adopting a safe strategy for ESD and a suitable choice of knife are both important ways of preventing perforation. Moreover, appropriate training and increasing experience can improve the endoscopic technique and can decrease the rate of perforation. In this review, we describe safe procedures in ESD to prevent complications, the complications of ESD and their management.

Detection of early colorectal cancer imaged with peanut agglutinin-immobilized fluorescent nanospheres having surface poly(N-vinylacetamide) chains

Peanut agglutinin (PNA)-immobilized fluorescent nanospheres were designed as a novel imaging agent for colonoscopy. PNA is a targeting moiety that binds to beta-D-galactosyl-(1-3)-N-acetyl-D-galactosamine, which is the terminal sugar of the Thomsen-Friedenreich antigen that is specifically expressed on the mucosal side of colorectal cancer cells. The in vivo performance of the imaging agent was evaluated using a human colorectal cancer orthotopic animal model. Human colorectal adenocarcinoma cell lines, HT-29, HCT-116, and LS174T, were implanted on the cecal serosa of immune-deficient mice. A loop of the tumor-bearing cecum was made, and the luminal side was treated with the imaging agent. Strong fluorescence was observed at several sites of the cecal mucosa, irrespective of cancer cell type. Microscopic histological evaluation of the cecal mucosa revealed that bright areas with fluorescence derived from the imaging agent and dark areas without the fluorescence well denoted the presence and absence, respectively, of the invasion of implanted cancer cells on the mucosal side. This good correlation showed that PNA-immobilized fluorescent nanospheres recognized millimeter-sized tumors on the cecal mucosa with high affinity and specificity.

Sigmoidectomy for radiation-induced sigmoid colonic dysplasia 35 years after radiotherapy for cervical cancer

Although radiation-induced colonic cancer is thought to arise from dysplasia, no guidelines exist for the treatment of such dysplasia. Therefore, clinicians must make treatment decisions for this condition on a case-by-case basis. Especially when the operative procedure is being decided, it is necessary to consider postoperative quality of life for advanced age. We report a patient who underwent sigmoidectomy for sigmoid colonic dysplasia that developed 35 years after radiation therapy. A 73-year-old woman who had undergone total hysterectomy and chemoradiotherapy for cervical cancer 35 years previously presented following a positive fecal occult blood test. Colonoscopy revealed sigmoid colonic dysplasia. To ensure reliable removal of the lesion, we elected to perform surgical resection. Given the patient's age, we performed sigmoidectomy rather than resecting the entire irradiated intestinal tract. The diagnosis of dysplasia was confirmed based on pathological findings, which included duct proliferation with partial structural atypia.

Effect of orally administered bovine lactoferrin on the growth of adenomatous colorectal polyps in a randomized, placebo-controlled clinical trial

Lactoferrin (LF), a secreted, iron binding glycoprotein originally discovered as a component of milk, is found in a variety of exocrine secretions and in the secondary granules of polymorphonuclear leukocytes. Animal experiments have shown that oral administration of bovine lactoferrin (bLF) exerts anticarcinogenesis effects in the colon and other organs of the rat. The aim of this study was to determine whether oral bLF could inhibit the growth of adenomatous colorectal polyps in human patients. A randomized, double-blind, controlled trial was conducted in 104 participants, ages 40 to 75 years, with polyps <or=5 mm in diameter and likely to be adenomas. Participants were assigned to receive placebo, 1.5-g bLF, or 3.0-g bLF daily for 12 months. Target adenomatous polyps were monitored by colonoscopy. Ingestion of 3.0-g bLF significantly retarded adenomatous polyp growth in participants 63 years old or younger. Removal of adenomatous colorectal polyps is done as a preventative measure against colorectal cancer; however, polyps can be overlooked, and when detected, polypectomy is not always 100% effective in eradicating a polyp. Our study suggests that daily intake of 3.0 g of bLF could be a clinically beneficial adjunct to colorectal polyp extraction.