Endoscopic mucosal resection of flat and depressed types of early colorectal cancer

The relationship between local recurrence and positive lateral margin after en bloc resection of colorectal neoplasm

BACKGROUND

The factors associated with recurrence of colonic neoplasm after endoscopic resection with a positive lateral margin are not well known. Thus, we evaluate the relationship between recurrence and positive lateral margin after endoscopic en bloc resection of colorectal neoplasm.

METHODS

A retrospective review of 9302 patients who underwent colonic endoscopic resection from January 2008 to January 2015. Of these, a total of 76 patients with positive lateral margins with clear evidence of the its location on endoscopic picture after endoscopic en bloc resection of colorectal neoplasm (>10 mm) were included.

RESULTS

Ten of 76 (13.2%) patients experienced recurrence during the follow-up period (mean f/u month, 21.7 ± 15.6). In cases with positive lateral margins, the 3- and 5-year local recurrence rate of colorectal neoplasm was 28.1% and 40.1%, respectively. The histological features of the recurrence group were as follows: one case of adenocarcinoma [from low-grade adenoma (LGA)]; two cases of high-grade adenoma (HGA) (one from HGA and one from LGA); and seven cases of LGA (four from adenocarcinoma, two from LGA, and one from HGA). The mean age of patients, locations of the lesions, and histologic type were not significantly associated with local recurrence. In multivariate Poisson regression analyses, total length of lateral margin involvement ≥8 mm (relative risk 12.51; 95% CI 1.11-140.34, p = .040) was a significant predictor of local recurrence.

CONCLUSIONS

Positive lateral margins ≥8 mm may be a reliable predictor of local recurrence after endoscopic en bloc resection of colorectal neoplasm.

Prediction of colorectal tumor grade and invasion depth through narrow-band imaging scoring

AIM

To determine the usefulness of assigning narrow-band imaging (NBI) scores for predicting tumor grade and invasion depth in colorectal tumors.

METHODS

A total of 161 colorectal lesions were analyzed from 138 patients who underwent endoscopic or surgical resection after conventional colonoscopy and magnifying endoscopy with NBI. The relationships between the surface and vascular patterns of the lesions, as visualized with NBI, and the tumor grade and depth of submucosa (SM) invasion were determined histopathologically. Scores were assigned to distinct features of the surface microstructures of tubular and papillary-type lesions. Using a multivariate analysis, a model was developed for predicting the tumor grade and depth of invasion based on NBI-finding scores.

RESULTS

NBI findings that correlated with a high tumor grade were associated with the “regular/irregular” (P < 0.0001) surface patterns and the “avascular area” pattern (P = 0.0600). The vascular patterns of “disrupted vessels” (P = 0.0714) and “thick vessels” (P = 0.0133) but none of the surface patterns were associated with a depth of invasion of ≥ 1000 μm. In our model, a total NBI-finding score ≥ 1 was indicative of a high tumor grade (sensitivity: 0.97; specificity: 0.24), and a total NBI-finding score ≥ 9 (sensitivity: 0.56; specificity: 1.0) was predictive of a SM invasion depth ≥ 1000 μm. Scores less than these cutoff values signified adenomas and a SM invasion depth < 1000 μm, respectively. Associations were also noted between selected NBI findings and tumor tissue architecture and histopathology.

CONCLUSION

Our multivariate statistical model for predicting tumor grades and invasion depths from NBI-finding scores may help standardize the diagnosis of colorectal lesions and inform therapeutic strategies.

Endoscopic submucosal dissection of 301 large colorectal neoplasias: outcome and learning curve from a specialized center in Europe

Background and study aims  Endoscopic submucosal dissection (ESD) allows en bloc resection of large colorectal lesions but ESD experience is limited outside Asia. This study evaluated implementation of ESD in the treatment of colorectal neoplasia in a Western center. Patients and methods  Three hundred and one cases of colorectal ESD (173 rectal and 128 colonic lesions) were retrospectively evaluated in terms of outcome, learning curve and complications. Results  Median size was 4 cm (range 1 - 12.5). En bloc resection was achieved in 241 cases amounting to an en bloc resection rate of 80 %. R0 resection was accomplished in 207 cases (69 %), RX and R1 were attained in 83 (27 %) and 11 (4 %) cases, respectively. Median time was 98 min (range 10 - 588) and median proficiency was 7.2 cm ² /h. Complications occurred in 24 patients (8 %) divided into 12 immediate perforations, five delayed perforations, one immediate bleeding and six delayed bleedings. Six patients (2 %), all with proximal lesions, had emergency surgery. Two hundred and four patients were followed up endoscopically and median follow-up time was 13 months (range 3 - 53) revealing seven recurrences (3 %). En bloc rate improved gradually from 60 % during the first period to 98 % during the last period. ESD proficiency significantly improved between the first study period (3.6 cm ² /h) and the last study period (10.8 cm ² /h). Conclusions  This study represents the largest material on colorectal ESD in the west and shows that colorectal ESD can be implemented in clinical routine in western countries after appropriate training and achieve a high rate of en bloc and R0 resection with a concomitant low incidence of complications. ESD of proximal colonic lesions should be attempted with caution during the learning curve because of higher risk of complications.

Adenoma of colorectal laterally spreading tumor nongranular type with biological phenotypic features similar to cancer

BACKGROUND AND AIM

Colorectal laterally spreading tumors (LSTs) are morphologically subdivided into granular (LST-G) and nongranular (LST-NG) categories. We aimed to elucidate the differences in oncogenic characteristics between the two types.

METHODS

Laterally spreading tumors resected by endoscopic submucosal dissection and surgery from March 2009 to May 2017 were examined for p53 positivity, Ki-67 labeling index (LI), microvessel density, degree of fibrosis, intensities of inducible nitric oxide synthase (iNOS) and nitrotyrosine (NT), and expression of acid mucins. We compared these factors between adenomas, noninvasive cancers, and invasive cancers, both LST-G and LST-NG.

RESULTS

Ninety-three LST-G (53 adenomas [LST-GA] and 40 cancers [LST-GC]) and 55 LST-NG (24 adenomas [LST-NGA] and 31 cancers [LST-NGC]) were evaluated. Although p53 positivity was lower in LST-GA than in LST-NGA (P < 0.001), there was no difference between LST-GC and LST-NGC. Ki-67 LI was higher in LST-NGA than in LST-GA (P < 0.001) and higher in LST-NGC than in LST-GC of noninvasive cancers (P < 0.001). Microvessel density and degree of fibrosis were higher in LST-NGA than in LST-GA (P < 0.001), and intensities of iNOS and NT were also higher in LST-NGA than in LST-GA (P < 0.001). Expression of acid mucins was lower in LST-NGA than in LST-GA (P < 0.001). Although there were significant differences in p53 positivity, Ki-67 LI, microvessel density, degree of fibrosis, intensities of iNOS and NT, and expression of acid mucins between LST-GA and LST-NGA, these factors were only slightly different between LST-GC and LST-NGC of invasive cancers.

CONCLUSIONS

Unlike LST-GA, LST-NGA possessed phenotypic features similar to cancer.

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.

Endoscopic Submucosal Dissection Decreases Additional Colorectal Resection for T1 Colorectal Cancer

BACKGROUND There are 3 methods of treating T1 colorectal cancer (T1 CRC), which include endoscopic resection, endoscopic resection followed by additional colorectal resection, and surgical resection. In this retrospective study, changes in the management of T1 CRC after introduction of endoscopic submucosal dissection (ESD) were investigated by comparison with the 10-year period before introduction of ESD. MATERIAL AND METHODS During a 20-year period from 1996 to 2015, 835 patients with T1 CRC were treated, including 331 patients before introduction of ESD (Group A) and 504 patients after introduction of ESD (Group B). Clinicopathological findings and treatment methods were compared between these 2 groups. RESULTS As the initial treatment, endoscopic treatment was performed in 185 patients (55.9%) in Group A and 288 (57.1%) in Group B. In Group B, ESD was performed in 161 patients (55.9%), accounting for more than half of the T1 CRC patients receiving endoscopic treatment. In Groups A and B, observation after endoscopic resection was selected for 54.2% and 67.3% of T1a patients, respectively (p=0.04). A similar trend was noted for T1b patients, and there was no significant difference of the treatment approach. Among all T1 CRC patients, the percentage undergoing observation after endoscopic resection was significantly higher in Group B than in Group A (34.3% vs. 26.9%, p=0.02), and the percentage of patients undergoing additional colorectal resection was significantly lower in Group B (22.8% vs. 29.0%, p=0.04). CONCLUSIONS After introduction of ESD, it was performed in more than half of all patients with T1 CRC undergoing endoscopic treatment. The percentage of patients undergoing observation following endoscopic resection of T1 CRC increased after introduction of ESD.

Histopathological Analysis of 173 Consecutive Patients with Colorectal Carcinoma: A Pathologist's View

Background

Worldwide, colorectal carcinomas are the third most common carcinomas in men and the second most common carcinomas in women. Pathological examination of rectum specimens requires special attention for correctly evaluating many prognostically important factors. In this study, we present pathological results of 173 lower anterior resection (LAR) and abdominoperineal resection (APR) specimens retrospectively evaluated.

Material/Methods

We included 173 LAR and APR specimens in this study. Patients were evaluated in the Istanbul Ekin Private Pathology Laboratory and underwent surgery at Çanakkale State Hospital, General Surgery Clinic.

Results

Of the 173 specimens, 15 (8.7%) were APR and 158 (91.3%) were LAR specimens. Ninety-four patients (54.3%) were males and 79 patients (45.7%) were females. The mean age of the patients was 63.5 years (range 26–90 years). In the histopathological examination, malignant neoplasm was detected in 172 of the cases (99.4%) and benign endometriosis was detected in 1 of the cases (0.6%). There were 151 (87.2%), 8 (4.6%), 5 (2.9%), 1 (0.6%), 1 (0.6%), 1 (0.6%), 1 (0.6%), 1 (0.6%), and 4 (2.3%) patients with adenocarcinoma, mucinous adenocarcinoma, intramucosal adenocarcinoma in the setting of a high-grade tubulovillous adenoma, synchronous colon/prostate adenocarcinoma, malignant melanoma, signet ring cell carcinoma, gastrointestinal stromal tumor, endometriosis, and adenocarcinoma diagnosed by the examination of colonoscopic biopsy specimens that showed complete regression with neoadjuvant therapy, respectively.

Conclusions

When evaluating specimens from patients with colorectal carcinoma, pathological evaluation, which is one of the most fundamental pillars in managing patients with cancer, must be performed carefully and meticulously. Each pathological parameter should be evaluated carefully and clinicians and pathologists should evaluate these cases together.

Genome-wide DNA methylation profiling of primary colorectal laterally spreading tumors identifies disease-specific epimutations on common pathways

Colorectal laterally spreading tumors (LSTs) grow to extremely large size while rarely invade deeply. Also, there is a low tendency to become cancerous. We used the Illumina Human Methylation 450K array to query the main epigenetic difference of LSTs. We built a discovery cohort with 10 matched cases, and a validation cohort with 9 additional matched cases. Our results suggest that LST displays significant decrease in DNA methylation, highlighted by the discovery of 1,018 hypomethylated intergenic regions (IGRs). Comparing to classic differentially methylated probes and regions that overlap transcription starting site and CpG island, IGR-regions were associated more closely with genes involved in functional biological processes and correlated with specific histone modifications. Hypomethylated IGR regions were often annotated as tissue-specific regulatory elements for noncolon tissues and were typically epigenetically silenced in normal colon mucosa. By integration of public data, we defined the commonality and specific epigenetic signatures for adenomas, LSTs and colon adenocarcinomas. Only 435 hypermethylated differentially methylated probes (DMPs) and differentially methylated regions (DMRs) and 517 hypomethylated DMPs and DMRs were shared by the three diseases. However, our pathway-level analysis discovered that genes in four pathways were common target of epimutations in LSTs, adenomas and CRCs. More interestingly, different diseases seem to employ distinct epigenetic insult to disturb specific pathways. Between LST and adenoma, we found eight pathways including Ras signaling and Rap1 signaling pathway were commonly targeted but the epimutation patterns were opposite. Comparison between precancerous conditions and invasive states revealed the key pathways governing the progression to malignancy, including PI3K-Akt pathways.

Delayed perforation after endoscopic submucosal dissection for mucosal colon cancer: A conservatively treated case

A 66-year-old man was diagnosed from colonoscopy as having a 40-mm elevated tumor in the cecum. With a preoperative diagnosis of intramucosal carcinoma, endoscopic submucosal dissection (ESD) was performed. The tumor was resected en bloc, yielding a specimen with a 66-mm diameter. No perforation was detected during the operation.Although neither abdominal pain nor fever was observed immediately after ESD, abdominal pain developed on the following day. Two days after ESD, the abdominal pain ceased. The patient was managed conservatively with fasting and intravenous antibiotic treatment. Four days after ESD, abdominal X-ray revealed marked gas retention. Computed tomography revealed pneumoperitoneum and a pelvic abscess, leading to a diagnosis of delayed perforation after colonic ESD and paralytic intestinal obstruction. A decompression tube was then inserted transnasally into the small intestine. Because a gradual decrease occurred in intestinal gas, the decompression tube was removed. Oral ingestion was resumed 13 days post-ESD.Delayed perforation after colonic ESD often requires emergency surgery. The present case was managed conservatively, despite paralytic intestinal obstruction. This approach is rarely employed for this condition and is therefore worth reporting.

Colorectal polyps located across a fold are difficult to resect completely using endoscopic mucosal resection: A propensity score analysis

Background

Incomplete polyp resection during colorectal endoscopic mucosal resection (EMR) might contribute to the development of interval cancer.

Objective

This retrospective study aimed to determine the incidence of incomplete polyp resection during EMR of colorectal polyps located across a fold compared with that of colorectal polyps located between folds.

Methods

In total, 262 patients with 262 lesions that were ≥10 mm in diameter and treated with conventional EMR were enrolled. The main outcome was the incidence of incomplete polyp resections. Propensity score matching and inverse probability of treatment weighting (IPTW) were performed to reduce the effects of selection bias.

Results

Fifty-seven lesions (21.8%) were incompletely resected. After propensity score matching, the lesions located across a fold were at higher risk of incomplete resection than those between folds (26/68, 38.2% vs 7/68, 10.3%; odds ratio (OR): 3.71; 95% confidence interval (CI): 1.61-8.56; p < 0.01). These findings persisted after adjusting for the differences at baseline using the IPTW method (OR: 3.63; 95% CI: 1.72-7.63; p = 0.001).

Conclusions

There is an increased risk of an incomplete polyp resection for a colorectal polyp that is located across a fold compared with that for a polyp that is located between folds.

Perforation and Postoperative Bleeding Associated with Endoscopic Submucosal Dissection in Colorectal Tumors: An Analysis of 398 Lesions Treated in Saga, Japan

Objective The aim of this study was to clarify the safety of colorectal endoscopic submucosal dissection (ESD) during the era of health insurance coverage starting from April 2012 in Japan. Methods Between April 2012 and May 2016, ESD was applied to 398 lesions in 373 patients. Risk factors for serious complications of colorectal ESD, perforation and post-ESD bleeding, were evaluated focusing on the resected specimen size, location, growth pattern, invasion depth, histopathology, postoperative clipping, and procedure time. In addition, the relationship between serious complications and patients' background characteristics was analyzed. Results Among 373 patients, perforation occurred in 12 patients and post-ESD bleeding in 19 patients. A univariate analysis showed that the risk factors for perforation were the lesion size, the resected specimen size, and a long operation time. A multivariate analysis showed that a long operation time was a risk factor for perforation during colorectal ESD. A univariate analysis indicated that significant risk factors for postoperative bleeding were a long operation time, rectal lesion, and cancer. All patients with serious complications were treated by an endoscopic procedure without blood transfusion or the need to convert to open surgery. Conclusion The present study suggests that colorectal ESD may be accepted with relative safety in Japan as a common therapeutic approach for early colorectal cancer.

Histopathologic study from a colorectal cancer screening in Chile: results from the first 2 years of an international collaboration between Chile and Japan

A national colorectal cancer (CRC) screening program began in Chile in 2012, which is an international collaboration between Japan and Chile and is based on a standardized protocol supported by Tokyo Medical and Dental University. We describe the results from the first 2 years of screening at one public hospital in Punta Arenas, Chile. Of 4124 asymptomatic individuals aged between 50 and 75 years, 485 participants with immunological fecal occult blood test values of at least 100 ng/ml and/or those with family histories of CRC underwent colonoscopies. Lesions were found in 291 participants, and 642 histologic samples were obtained. Chilean pathologists made the initial histologic diagnoses, and a Japanese pathologist reviewed the histologic slides and analyzed the results. Of the 291 participants with lesions, 60 (20.6%) were diagnosed with adenocarcinomas, of which 50 (83.3%) were early-phase adenocarcinomas (pTis or pT1), and 163 (56.0%) were diagnosed with conventional adenomas, of which 96 (58.9%) were high-risk adenomas. The cancer prevalence within the screened population was 1.5% (60 of 4124). The colonoscopy cancer detection rate was 12.4% (60 of 485). Notably, we detected one flat-depressed (0-IIc) lesion that measured 5 mm and had invaded the submucosa. The findings from this screening program are the first to show the histopathologic distributions of consecutive lesions and the high incidence of CRC in Chile. The high detection rates for high-risk adenomas and cancer support the feasibility of early CRC screening and its potential to reduce the mortality associated with CRC.

Does Early Polypoid Colorectal Cancer with Depression Have a Pathway Other than Adenoma-Carcinoma Sequence?

In the carcinogenesis of colorectal cancer, the concept of adenoma-carcinoma sequence is widely accepted. In this pathway, polypoid adenoma develops into early polypoid cancer and then progresses to advanced cancer. Alternatively, some groups insist that in the de novo pathway in which early cancers develop without preexisting adenoma, flat or depressed early cancers develop into advanced cancer. According to these two different concepts of carcinogenesis, early polypoid cancers may include two distinct types of lesions, early polypoid cancers without central depression via the adenoma-carcinoma sequence and early polypoid cancers with central depression via de novo carcinogenesis. We analyzed 45 submucosal cancer specimens histologically diagnosed as polypoid by clinicopathological features and K-ras mutation in early polypoid cancers with and without depression to clarify whether there was a difference between the two groups. No significant difference in clinicopathological features was found between the two groups. Also, a high incidence of K-ras mutation was observed in both groups. This suggests that early polypoid cancers with depression have a similar genetic background to polypoid cancers without depression, which follows the adenoma-carcinoma sequence. It is possible that whether or not the tumor has a depression does not indicate the distinct pathway of colorectal carcinogenesis.

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.

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.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2016 for the treatment of colorectal cancer

Japanese mortality due to colorectal cancer is on the rise, surpassing 49,000 in 2015. Many new treatment methods have been developed during recent decades. The Japanese Society for Cancer of the Colon and Rectum Guidelines 2016 for the treatment of colorectal cancer (JSCCR Guidelines 2016) were prepared to show standard treatment strategies for colorectal cancer, to eliminate disparities among institutions in terms of treatment, to eliminate unnecessary treatment and insufficient treatment, and to deepen mutual understanding between health-care professionals and patients by making these Guidelines available to the general public. These Guidelines were prepared by consensus reached by the JSCCR Guideline Committee, based on a careful review of the evidence retrieved by literature searches, and in view of the medical health insurance system and actual clinical practice settings in Japan. Therefore, these Guidelines can be used as a tool for treating colorectal cancer in actual clinical practice settings. More specifically, they can be used as a guide to obtaining informed consent from patients and choosing the method of treatment for each patient. As a result of the discussions held by the Guideline Committee, controversial issues were selected as Clinical Questions, and recommendations were made. Each recommendation is accompanied by a classification of the evidence and a classification of recommendation categories based on the consensus reached by the Guideline Committee members. Here we present the English version of the JSCCR Guidelines 2016.

Colorectal endoscopic submucosal dissection (ESD) in the West - when can satisfactory results be obtained? A single-operator learning curve analysis

OBJECTIVES

Up to date we lack a detailed description of the colorectal endoscopic submucosal dissection (ESD) learning curve, that would represent the experience of the Western center. The aim of this study was to define the critical points of the learning curve and to draw up lesions qualification guidelines tailored to the endoscopists experience.

MATERIALS AND METHODS

We have carried out a single center prospective study. Between June 2013 and December 2016, 228 primary colorectal lesions were managed by ESD procedure. In order to create a learning curve model and to carry out the analysis the cases were divided into six periods, each consisting of 38 cases.

RESULTS

The overall en bloc resection rate was 79.39%. The lowest en bloc resection rate (52.36%) was observed in the first period. After completing 76 procedures, the resection rate surged to 86% and it was accompanied by the significant increase in the mean procedure speed of ≥9 cm²/h. Lesions localization and diameter had a signification impact on the outcomes. After 76 procedures, en bloc resection rate of 90.9 and 90.67% were achieved for the left side of colon and rectum, respectively. In the right side of colon statistically significant lower resection rate of 67.57% was observed.

CONCLUSION

We have proved that in the setting of the Western center, colorectal ESD can yield excellent results. It seems that the key to the success during the learning period is 'tailoring' lesions qualification guidelines to the experience of the endoscopist, as lesions diameter and localization highly influence the outcomes.

Post-colonoscopy colorectal cancer rate in the era of high-definition colonoscopy

AIM

To investigate the post-colonoscopy colorectal cancer (PCCRC) rate for high-definition (HD) colonoscopy compared with that for standard-definition colonoscopy reported previously.

METHODS

Using medical records at Sano Hospital (SH) and Dokkyo Medical University Koshigaya Hospital (DMUKH), we retrospectively obtained data on consecutive patients diagnosed as having CRC between January 2010 and December 2015. The definition of PCCRC was diagnosis of CRC between 7 and 36 mo after initial high-definition colonoscopy that had detected no cancer, and patients were divided into a PCCRC group and a non-PCCRC group. The primary outcome was the rate of PCCRC for HD colonoscopy. The secondary outcomes were factors associated with PCCRC and possible reason for occurrence of early and advanced PCCRC.

RESULTS

Among 892 CRC patients, 11 were diagnosed as having PCCRC and 881 had non-PCCRC. The PCCRC rate was 1.7% (8/471) at SH and 0.7% (3/421) at DMUKH. In comparison with the non-PCCRC group, the PCCRC group had a significantly higher preponderance of smaller tumors (39 mm vs 19 mm, P = 0.002), a shallower invasion depth (T1 rate, 25.4% vs 63.6%, P = 0.01), a non-polypoid macroscopic appearance (39.0% vs 85.7%, P = 0.02) and an earlier stage (59.7% vs 90.9%, P = 0.03). Possible reasons for PCCRC were "missed or new" in 9 patients (82%), "incomplete resection" in 1 (9%), and "inadequate examination'" in 1 (9%). Among 9 "missed or new" PCCRC, the leading cause was non-polypoid shape for early PCCRC and blinded location for advanced PCCRC.

CONCLUSION

The PCCRC rate for HD colonoscopy was 0.7%-1.7%, being lower than that for standard-definition colonoscopy (1.8%-9.0%) reported previously employing the same methodology.

Histopathologic risk factors for lymph node metastasis in patients with T1 colorectal cancer

PURPOSE

Evaluating the risk of lymph node metastasis (LNM) is critical for determining subsequent treatments following endoscopic resection of T1 colorectal cancer (CRC). This study analyzed histopathologic risk factors for LNM in patients with T1 CRC.

METHODS

This study involved 745 patients with T1 CRC who underwent endoscopic (n = 97) or surgical (n = 648) resection between January 2001 and December 2015 at the National Cancer Center, Korea. LNM in endoscopically resected patients, which could not be evaluated directly, was estimated indirectly based on follow-up results and histopathologic reports of salvage surgery. The relationships of depth of submucosal invasion, histologic grade, budding, vascular invasion, and background adenoma with LNM were evaluated statistically.

RESULTS

Of the 745 patients, 91 (12.2%) were found to be positive for LNM. Univariate and multivariate analyses identified deep submucosal invasion (P = 0.010), histologic high grade (P < 0.001), budding (P = 0.034), and vascular invasion (P < 0.001) as risk factors for LNM. Among the patients with one, two, three, and four risk factors, 6.0%, 18.7%, 36.4%, and 100%, respectively, were positive for LNM.

CONCLUSION

Deep submucosal invasion, histologic high grade, budding, and vascular invasion are risk factors for LNM in patients with T1 colorectal cancer. If any of these risk factors are present, additional surgery following endoscopic resection should be determined after considering the potential risk of LNM and each patient's situation.

[Expression of Wnt and integrin pathways in colorectal laterally spreading tumors and their correlation with endoscopic subtypes]

OBJECTIVE

To investigate the expression of Wnt and integrin pathways in colorectal laterally spreading tumors (LSTs) and their correlation with the different endoscopic subtypes of LSTs to better understand the special growth mechanism of LSTs.

METHODS

Fifty-two patients with colorectal LSTs were randomly selected from the cases diagnosed between January 1, 2010 and June 10, 2015 in our hospital, including 37 of nodular mixed type (LST-G-M), 60 of homogeneous type (LST-G-H), 5 of flat elevated type (LST-NG-FE), and 4 of pseudodepressed type (LST-NG-PD). The expression of β-catenin, phospho- GSK-3β, paxillin and ILK in 52 colorectal LSTs and 15 protruded adenomas (PAs) were investigated by immunohistochemical staining. The correlation of β-catenin, phospho-GSK-3β, paxillin and ILK expressions among the endoscopic subtypes of LSTs were analyzed.

RESULTS

β-catenin expression was significantly higher in LSTs than in Pas (P<0.05). β-catenin, phospho-GSK-3β, paxillin and ILK expressions were significantly higher in LST-NG-PD than in Pas (P<0.05). The expressions of β-catenin, phospho-GSK-3β and ILK expression were significantly correlated in LSTs (P<0.05) but not in PAs (P>0.05).

CONCLUSION

The macroscopic feature of LST-NG-PD may result from a special mechanism of development distinct from other endoscopic subtypes; ILK may play a role in regulating Wnt signaling in LSTs.

A simple endoscopic scoring system to differentiate between duodenal adenoma and carcinoma

BACKGROUND AND STUDY AIMS

 Diagnosis of nonampullary duodenal low grade adenoma (Vienna classification category 3, VCL 3) and high grade adenoma/carcinoma (VCL 4 or higher) is important for clinical management decisions. However, there are no criteria based on which endoscopic diagnosis can differentiate between VCL3 and VCL4 or higher. This study aimed to establish simple diagnostic criteria to differentiate between VCL3 and VCL4 or higher.

PATIENTS AND METHODS

 This retrospective study included patients with superficial nonampullary duodenal epithelial tumors (NADETs) who underwent tumor resection between June 2004 and November 2016 at a single cancer center hospital. Using patient demographics and endoscopic findings from 2004 to 2013, variables related to the final histology of VCL4 or higher were analyzed, and a predictive model was developed. Validation analysis was performed on patients treated between 2014 and 2016.

RESULTS

 A total of 150 lesions in 134 patients were included. Lesion diameter, reddish color, depression, heterogeneous or no nodularity, and mixed or depressed macroscopic types were significantly predictive of VCL4 or higher. A predictive score model was developed and a score of 3 points was defined as an appropriate cutoff for predicting VCL4 or higher. In the validation analysis, the accuracy rate of VCL4 or higher diagnosis was 86 % when the score was ≥ 3 points. Scores between patients with VCL3 and VCL4 or higher were significantly different ( P  = 0.0004).

CONCLUSIONS

 A simple and useful endoscopic scoring system was developed to preoperatively differentiate between VCL3 and VCL4 or higher among superficial NADETs.

Local Excision of Rectal Cancer

Local excision (LE) of early-stage rectal cancer avoids the morbidity associated with radical surgery but has historically been associated with inferior oncologic outcomes. Newer techniques, including transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS), have been developed to improve the quality of LE and extend the benefits of LE to tumors in the more proximal rectum. This article provides an overview of conventional LE, TEM, and TAMIS techniques, including indications for their use and pertinent literature on their associated outcomes for rectal cancer.

The Difficult Colorectal Polyp

Difficult colorectal polyps represent lesions that pose a challenge to traditional endoscopic snare polypectomy. These polyps have historically been managed by surgical resection. Currently, several less invasive options are available to avoid colectomy. Repeat colonoscopy and snare polypectomy by an expert endoscopist, endoscopic mucosal resection, endoscopic submucosal dissection, and combined endoscopic and laparoscopic surgery have been developed to remove difficult polyps without the need for formal surgical resection. Patients with rectal polyps have the advantage of additional transanal minimally invasive techniques to enhance their resectability. Today, most colorectal polyps can be managed without the need for formal surgical resection.

The prognostic value of lymph node yield in the earliest stage of colorectal cancer: a multicenter cohort study

BACKGROUND

In patients with stage II colorectal cancer (CRC) the number of surgically retrieved lymph nodes (LNs) is associated with prognosis, resulting in a minimum of 10-12 retrieved LNs being recommended for this stage. Current guidelines do not provide a recommendation regarding LN yield in T1 CRC. Studies evaluating LN yield in T1 CRC suggest that such high LN yields are not feasible in this early stage, and a lower LN yield might be appropriate. We aimed to validate the cut-off of 10 retrieved LNs on risk for recurrent cancer and detection of LN metastasis (LNM) in T1 CRC, and explored whether this number is feasible in clinical practice.

METHODS

Patients diagnosed with T1 CRC and treated with surgical resection between 2000 and 2014 in thirteen participating hospitals were selected from the Netherlands Cancer Registry. Medical records were reviewed to collect additional information. The association between LN yield and recurrence and LNM respectively were analyzed using 10 LNs as cut-off. Propensity score analysis using inverse probability weighting (IPW) was performed to adjust for clinical and histological confounding factors (i.e., age, sex, tumor location, size and morphology, presence of LNM, lymphovascular invasion, depth of submucosal invasion, and grade of differentiation).

RESULTS

In total, 1017 patients with a median follow-up time of 49.0 months (IQR 19.6-81.5) were included. Four-hundred five patients (39.8%) had a LN yield ≥ 10. Forty-one patients (4.0%) developed recurrence. LN yield ≥ 10 was independently associated with a decreased risk for recurrence (IPW-adjusted HR 0.20; 95% CI 0.06-0.67; P = 0.009). LNM were detected in 84 patients (8.3%). LN yield ≥ 10 was independently associated with increased detection of LNM (IPW-adjusted OR 2.27; 95% CI 1.39-3.69; P = 0.001).

CONCLUSIONS

In this retrospective observational study, retrieving < 10 LNs was associated with an increased risk of CRC recurrence, advocating the importance to perform an appropriate oncologic resection of the draining LNs and diligent LN search when patients with T1 CRC at high-risk for LNM are referred for surgical resection. Given that both gastroenterologists, surgeons and pathologists will encounter T1 CRCs with increasing frequency due to the introduction of national screening programs, awareness on the consequences of an inadequate LN retrieval is of utmost importance.

Clinical outcomes after endoscopic submucosal dissection for colorectal neoplasia: a systematic review and meta-analysis

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) is an endoscopic resection technique for lesions suspicious of superficial malignancy. It is performed using an ESD knife on its own (standard technique) or by the sequential use of a knife and a snare (hybrid technique). The experience with these techniques is different in Asian and non-Asian countries. We performed a systematic review and meta-analysis of available evidence on colorectal ESD.

METHODS

Electronic databases were searched up to August 2016 for studies evaluating R0, en bloc resection, and adverse event rates of both techniques for the treatment of colorectal lesions. Proportions were pooled by a random effects model.

RESULTS

Ninety-seven studies (71 performed in Asia) evaluated the standard technique and 12 studies (7 in Asia) the hybrid technique. The R0 resection rate of the standard technique was 82.9%, and it was significantly lower in non-Asian versus Asian countries: 71.3% versus 85.6%. The en bloc resection rate was 91% and was significantly lower in non-Asian versus Asian countries (81.2% vs 93%, respectively). Surgery was needed in 1.1% of the ESD-related adverse events, with a significant difference between non-Asian and Asian countries (3.1% vs 0.8%). The R0 and en bloc resection rates with the hybrid technique were significantly lower than those achieved with the standard technique: 60.6% and 68.4%, respectively, with similar adverse event rates.

CONCLUSIONS

In non-Asian countries the standard ESD technique is still failing to achieve acceptable levels of performance. The hybrid technique showed low R0 resection rates and should not be considered as an adequate alternative to the standard technique.

Analysis of molecular alterations in laterally spreading tumors of the colorectum

BACKGROUND

Colorectal laterally spreading tumors (LSTs) are classified into LST-Gs and LST-NGs, according to macroscopic findings. In the present study, we determined the genetic and epigenetic alterations within colorectal LSTs and protruding adenomas.

METHODS

A crypt isolation method was used to isolate DNA from tumors and normal glands of 73 macroscopically verified colorectal LSTs (histologically defined adenomas; 38 LST-Gs and 35 LST-NGs) and 36 protruding adenomas. The DNA was processed using polymerase chain reaction (PCR) microsatellite assays, single-strand conformation polymorphism (SSCP) assays, and pyrosequencing to detect chromosomal allelic imbalance (AI), mutations in APC, KRAS, and TP53, and the methylation of MLH1, MGMT, CDKN2A, HPP1, RASSF2A, SFRP1, DKK1, ZFP64, and SALL4 genes. In addition, methylation status was examined using the following set of markers: MIN1, MINT2, MINT31, MLH1, and CDKN2A (with classification of negative/low and high). Microsatellite instability (MSI) was also examined.

RESULTS

5q AI and methylation of the SFRP1 and SALL4 genes were common molecular events in both LST-Gs and LST-NGs. Neither MSI nor mutations in BRAF ware observed in the LSTs. TP53 mutations were rarely found in LSTs. The frequencies of KRAS and APC mutations and the methylation levels of ZFP64, RASSF2A, and HPP1 genes were significantly higher in LST-Gs than in LST-NGs. Protruding adenomas showed alterations common to LST-Gs. Negative/low methylation status was common among the three types of tumors.

CONCLUSION

Combined genetic and epigenetic data suggested that the molecular mechanisms of tumorigenesis were different between LST-Gs and LST-NGs.

Advances in image enhancement in colonoscopy for detection of adenomas

High-quality colonoscopy is mandatory to prevent adenoma recurrence and colorectal cancer. In the past few years, technical advances have been developed with the purpose of improving adenoma detection rate (ADR), one of the most important validated colonoscopy quality benchmarks. Several techniques or devices are used to optimize visualization: observation techniques; add-on devices; auxiliary imaging devices; colonoscopes with increased field of view; and colonoscopes with an integrated inflatable reusable balloon. Image-enhanced endoscopy (IEE) facilitates the detection and characterization of polyps and especially nonpolypoid colorectal neoplasms. Indigo carmine is the most frequently used dye in colonoscopy as it deposits in depressed areas, improving detection of flat and depressed lesions. Virtual chromoendoscopy has emerged as an effective contrast enhancement technology without the limitation of preparing dyes and applying them through the colonoscope working channel. Narrow-band imaging (NBI) enhances the capillary pattern and surface of the mucosa using optical filters, and second-generation NBI provides a twofold brighter image than the previous system, yielding promising ADR results. Moreover, a second-generation blue laser imaging system, LASEREO, has been reported to improve not only polyp detection rate but also ADR, becoming a promising IEE modality. Herein, we describe technical advances in colonoscopy imaging and their effect on ADR.

Risk for Incomplete Resection after Macroscopic Radical Endoscopic Resection of T1 Colorectal Cancer: A Multicenter Cohort Study

OBJECTIVES

The decision to perform secondary surgery after endoscopic resection of T1 colorectal cancer (CRC) depends on the risk of lymph node metastasis and the risk of incomplete resection. We aimed to examine the incidence and risk factors for incomplete endoscopic resection of T1 CRC after a macroscopic radical endoscopic resection.

METHODS

Data from patients treated between 2000 and 2014 with macroscopic complete endoscopic resection of T1 CRC were collected from 13 hospitals. Incomplete resection was defined as local recurrence at the polypectomy site during follow-up or malignant tissue in the surgically resected specimen in case secondary surgery was performed. Multivariate regression analysis was performed to analyze factors associated with incomplete resection.

RESULTS

In total, 877 patients with a median follow-up time of 36.5 months (interquartile range 16.0-68.3) were included, in whom secondary surgery was performed in 358 patients (40.8%). Incomplete resection was observed in 30 patients (3.4%; 95% confidence interval (CI) 2.3-4.6%). Incomplete resection rate was 0.7% (95% CI 0-2.1%) in low-risk T1 CRC vs. 4.4% (95% CI 2.7-6.5%) in high-risk T1 CRC (P=0.04). Overall adverse outcome rate (incomplete resection or metastasis) was 2.1% (95% CI 0-5.0%) in low-risk T1 CRC vs. 11.7% (95% CI 8.8-14.6%) in high-risk T1 CRC (P=0.001). Piecemeal resection (adjusted odds ratio 2.60; 95% CI 1.20-5.61, P=0.02) and non-pedunculated morphology (adjusted odds ratio 2.18; 95% CI 1.01-4.70, P=0.05) were independent risk factors for incomplete resection. Among patients in whom no additional surgery was performed, who developed recurrent cancer, 41.7% (95% CI 20.8-62.5%) died as a result of recurrent cancer.

CONCLUSIONS

In the absence of histological high-risk factors, a 'wait-and-see' policy with limited follow-up is justified. Piecemeal resection and non-pedunculated morphology are independent risk factors for incomplete endoscopic resection of T1 CRC.

Transanal Endoscopic Operation Versus Conventional Transanal Excision for Rectal Tumors: Case-Matched Study with Propensity Score Matching

BACKGROUNDS

Although transanal endoscopic surgery is practiced worldwide, there is no consensus on comparative outcomes between transanal endoscopic operation (TEO) and transanal excision (TAE). In this study, we reviewed our experiences with these techniques and compared patients who underwent TEO and TAE using propensity score matching (PSM).

METHODS

A total of 207 patients underwent local rectal tumor excision between January 2008 and November 2015. To overcome selection bias, we used PSM to achieve a one-to-one TEO: TAE ratio. We included baseline characteristics, age, sex, surgeon, American Society of Anesthesiologists score, tumor location (clockwise direction), involved circumference quadrants, tumor size, and pathology.

RESULTS

After PSM, 72 patients were included in each group. The tumor distance from the anal verge was higher in the TEO group (8.0 [5-10] vs. TAE: 4.0 [3-5], p < 0.001). Complication rates did not differ between the groups (TEO: 8.3% vs. TAE: 11.1%, p = 0.39). TEO was associated with a shorter hospital stay (3.01 vs. 4.68 days, p = 0.001), higher negative margin rate (95.8 vs. 86.1%, p = 0.039), and non-fragmented specimen rate vs. TAE (98.6 vs. 90.3%, p = 0.029).

CONCLUSIONS

TEO was more beneficial for patients with higher rectal tumors. Regardless of tumor location, involved circumference quadrants, and tumor size, TEO may more effectively achieve negative resection margins and non-fragmented specimens. Consequently, although local excision method according to tumor distance may be important, TEO will become the standard for rectal tumors.

Efficacy of hybrid endoscopic submucosal dissection (ESD) as a rescue treatment in difficult colorectal ESD cases

BACKGROUND AND AIM

Endoscopic submucosal dissection (ESD), which provides a higher en bloc resection rate than conventional endoscopic mucosal resection (EMR), is considered to be a useful treatment option for large colorectal tumors. However, colorectal ESD is not widely used because of its technical difficulty, risk of complications and time required. To overcome these drawbacks, a simpler modified technique, ESD with snaring (hybrid ESD), has been developed. The aim of the present study was to retrospectively compare the safety and efficacy of hybrid ESD and conventional ESD for colorectal tumors.

METHODS

Between September 2008 and June 2016, ESD was carried out on 137 lesions and hybrid ESD on 27 lesions. All hybrid ESD cases were carried out as a rescue treatment in difficult ESD cases. We retrospectively investigated procedure time, and the rates of en bloc resection, perforation, bleeding, and local recurrence.

RESULTS

In the hybrid ESD group, procedure time was shorter compared with the ESD group (108 ± 59.5 min vs 122 ± 72.2 min), but the en bloc resection rate was lower (66.7% vs 94.2%). However, there were no significant differences in procedure time, or in rates of en bloc resection, perforation and bleeding between the two groups. Local recurrence did not develop in any of our cases.

CONCLUSIONS

Hybrid ESD as a rescue treatment in difficult ESD cases may be less effective for en bloc resection of large colorectal tumors. Indication for hybrid ESD may be limited to scheduled treatment from the outset and emergency cases with patients who present unstable vital signs during ESD.

Colonic Laterally Spreading Tumor Diagnosed as an Early Cancer and Treated with Endoscopic Mucosal Resection: A Case Report and Review of Literature

Laterally spreading tumors (LSTs) are generally defined as superficial lesions ≥10 mm in diameter that typically extend laterally rather than vertically along the colonic wall. Such lesions are now increasingly reported because of increased awareness and the introduction of chromo and magnifying colonoscopy. Although the clinicopathological characteristics and the efficacy of endoscopic management of LSTs have been defined in Japanese cohorts, reports from the Middle East are lacking where surgical resection is the mainstay of treatment. We report a case with an LST about 20 cm from anal verge removed by endoscopic mucosal resection. After histopathological evaluation of the removed specimen, we categorized the patient as having high risk early colon cancer. The intensive follow-up as an additional treatment strategy was chosen for the patient. This review addresses the management of early carcinoma in colorectal polyp with reference to proper preoperative assessment, treatment selection with special attention to role of biomarkers, the need for additional treatment on the basis of the presence of risk factors and endoscopic follow-up after treatment.

Comparative clinicopathological characteristics of colon and rectal T1 carcinoma

Lymph node metastasis significantly influences the management of patients with colorectal carcinoma. It has been observed that the biology of colorectal carcinoma differs by location. The aim of the current study was to retrospectively compare the clinicopathological characteristics of patients with colon and rectal T1 carcinomas, particularly their rates of lymph node metastasis. Of the 19,864 patients who underwent endoscopic or surgical resection of colorectal neoplasms at Showa University Northern Yokohama Hospital, 557 had T1 surgically resected carcinomas, including 457 patients with colon T1 carcinomas and 100 patients with rectal T1 carcinomas. Analysed clinicopathological features included patient age, gender, tumor size, morphology, tumor budding, invasion depth, vascular invasion, histological grade, lymphatic invasion and lymph node metastasis. Rectal T1 carcinomas were significantly larger than colon T1 carcinomas (mean ± standard deviation: 23.7±13.1 mm vs. 19.9±11.0 mm, P<0.01) and were accompanied by significantly higher rates of vascular invasion (48.0% vs. 30.2%, P<0.01). Significant differences were not observed among any other clinicopathological factors. In conclusion, tumor location itself was not a risk factor for lymph node metastasis in colorectal T1 carcinomas, even though on average, rectal T1 carcinomas were larger and accompanied by a significantly higher rate of vascular invasion than colon T1 carcinomas.

Management of Rectal Polyps

Colorectal cancer is one of the most common causes of cancer and cancer morbidity in the United States. In comparison to colon polyps, rectal polyps pose a unique challenge. Advances in endoscopic techniques have allowed for more thorough rectal adenoma detection and removal; however, there remains a concern over piecemeal resection and negative resection margins. Advances in transanal excision techniques, such as transanal endoscopic microsurgery, have been proposed for the removal of benign polyps as well as some early stage rectal cancers, with emphasis on proper patient selection. This review will discuss the current endoscopic and surgical considerations of both benign and malignant rectal polyps.

Ectopic Gastric and Intestinal Phenotypes, Neuroendocrine Cell Differentiation, and SOX2 Expression Correlated With Early Tumor Progression in Colorectal Laterally Spreading Tumors

INTRODUCTION

The significance of the ectopic gastric phenotype remains unclear in patients with colorectal laterally spreading tumors (LSTs). We investigated clinicopathologic differences among LST subtypes, aiming to identify factors indicative of malignant transformation and invasion that are linked to ectopic gastric phenotype and tumor progression.

MATERIALS AND METHODS

We analyzed the morphologic characteristics of 105 colorectal LSTs resected by endoscopic submucosal dissection. LSTs were classified into 2 subtypes: granular (G-LST) and nongranular (NG-LST). Resected LSTs were analyzed histologically and were immunohistochemically stained for MUC5AC, MUC6, chromogranin A, CD10, and SOX2.

RESULTS

The 105 LSTs included 60 G-LSTs and 45 NG-LSTs. By histology, G-LSTs comprised 5 adenomas with low-grade dysplasia (LAs), 45 adenomas with high-grade dysplasia (HAs), and 10 adenocarcinomas invading the submucosa (SMs). NG-LSTs comprised 8 LAs, 25 HAs, and 12 SMs. MUC5AC positivity was significantly higher in G-LSTs compared to NG-LSTs (P = .002), and MUC5AC positivity in HA lesions was significantly higher than in LA lesions (P = .01). MUC6 and SOX2 positivity in SM G-LSTs, and chromogranin A positivity in SM NG-LSTs were significantly higher than in HAs (P = .01, .01, and .03, respectively). CD10 positivity in SM NG-LSTs was significantly higher than in HAs and LAs (P = .02 and .01, respectively).

CONCLUSION

Ectopic gastric and intestinal phenotypes, neuroendocrine cell differentiation, and SOX2 expression differ according to tumor grade in colorectal LSTs, and these markers are correlated with early tumor progression in each LST subtype.

Long-term outcomes of locally or radically resected T1 colorectal cancer

AIM

Little is known about the long-term outcome of T1 colorectal cancer (CRC) following curative resection. The present study addressed the long-term outcome of locally or radically resected T1 CRCs.

METHOD

A total of 430 patients with T1 CRC who underwent local or radical resection were considered. Unfavourable histological factors were defined as positive resection margin, deep submucosal invasion, vascular invasion, Grade 3 and budding. The patients were classified as low-risk (unfavourable histological factor negative, n = 65) or high-risk (unfavourable histological factor positive, n = 365).

RESULTS

Over a median follow-up of 78.4 months, disease recurred in 16 (3.7%) patients in the high-risk group, and no recurrence in the low-risk group. Resection type and vascular invasion were significantly associated with recurrence. In the vascular invasion (+) high-risk group, both 5-year disease-free survival rate and 5-year overall survival rate were significantly associated with resection type (radical 94.6%, local 43.8%, P < 0.001, and radical 99.1%, local 66.7%, P < 0.001). In the vascular invasion (-) high-risk group, 5-year disease-free survival rate was also significantly associated with resection type (radical 98.9%, local 84.7%, P = 0.001). However, 5-year overall survival rate was not associated with resection type (radical 98.9%, local 95.2%, P = 0.816).

CONCLUSION

Local resection may be effective and oncologically safe in low-risk T1 CRC. Although additional surgery should be recommended for the locally resected high-risk T1 CRC cases, intensive surveillance without additional surgery and timely salvage operation may offer another treatment option, if vascular invasion is negative.

The risk of lymph node metastasis makes it unsafe to expand the conventional indications for endoscopic treatment of T1 colorectal cancer: A retrospective study of 428 patients

Though endoscopic treatment is an option for T1 colorectal cancer (CRC), the optimal indications and long-term outcomes of this strategy need to be validated. Therefore, the aim of this study is to investigate long-term outcomes of endoscopy versus surgery and optimal indications for endoscopic treatment of T1 CRC.This retrospective study included 428 T1 CRC patients treated with initial endoscopy (n = 224) or surgery (n = 204) at Severance Hospital between 2005 and 2012. Patients were subdivided into 4 groups according to conventional indications (CIs) for endoscopic treatment: negative lateral/vertical margins; submucosal invasion depth within 1000 μm; no lymphovascular invasion (LVI); well or moderately differentiated. For prognosis evaluation, short-term outcomes (resection margin and complications) and long-term outcomes (recurrence and cancer-specific mortality) were evaluated.Endoscopic treatment achieved en bloc resection in 86.6% of 224 patients. Recurrence and mortality did not differ between the endoscopy and surgery groups with or without CIs. For patients with CIs, although 80 patients were treated endoscopically with 1 (1.3%) recurrence and 0 mortality, 75 patients were treated surgically with 2 (2.7%) recurrence and 1 (1.3%) mortality. Multivariate analysis revealed that LVI positivity and poorly differentiated histology were independently associated with lymph node metastasis (LNM; P < 0.001 and P = 0.001, respectively).To determine whether the depth of submucosal invasion among criteria of CIs could be extended for endoscopic treatment, LNM was analyzed by extending the depth of submucosal invasion. There was no LNM in 155 patients within conventional indication. When the depth of submucosal invasion was extended up to 1500 μm, LNM was occurred (1/197 patient [0.5%]). In addition, when the depth of submucosal invasion was extended up to 2000 μm, LNM was increased (4/271 patient [1.5%]).Endoscopic treatment is safe, effective, and is associated with favorable long-term outcomes compared to surgery for initial treatment of T1 CRC patients with CIs. However, the risk of LNM makes it unsafe to extend the CIs for endoscopic therapy in these patients.

Endoluminal Therapy in Colorectal Cancer

Appropriate endoscopic resection for colorectal polyps can present a challenge to endoscopists, as these lesions may harbor malignancy. With recent advances in endoscopy, however, we are now entering an exciting frontier of endoscopic therapy for gastrointestinal lesions. These techniques include endoluminal mucosal resection and endoscopic submucosal dissection, which may be utilized on several colonic lesions. This article will discuss these principle endoscopic techniques, their outcomes, and briefly highlight their influence on endoscopic interventions, including transanal endoscopic microsurgery and natural orifice transluminal endoscopic surgery.

Interobserver variability amongst gastrointestinal pathologists in assessing prognostic parameters of malignant colorectal polyps: a cause for concern

BACKGROUND

Malignant colorectal polyps (MCRP) have become a major challenge in the field of coloproctology from diagnosis to full treatment. One important facet of the challenge is the histopathological staging of the lesion and identifying various prognostic parameters. The primary aim of this study was to find the interobserver variation amongst 4 experienced gastrointestinal pathologists when assessing important parameters and staging systems (Haggitt, Kikuchi and Ueno) in MCRPs.

METHODS

Four experienced gastrointestinal pathologists independently assessed 56 cases of MCRP, and each pathologist completed a pro forma for each case. The results were collated and statistically analysed.

RESULTS

There was a significant variation in the assessments using the various published staging systems agreed upon on important prognostic parameters.

CONCLUSIONS

None of the staging systems used is suitable for all polyp types or has good reproducibility. There is an urgent need to make pathologists' assessment of MCRPs easier and more reproducible.

Epigenetic silencing of NTSR1 is associated with lateral and noninvasive growth of colorectal tumors

Our aim was to identify DNA methylation changes associated with the growth pattern and invasiveness of colorectal cancers (CRCs). Comparison of the methylation statuses of large (≥20 mm in diameter along the colonic surface) noninvasive tumors (NTs) and small (<20 mm in diameter along the colonic surface) invasive tumors (ITs) using CpG island microarray analysis showed neurotensin receptor 1 (NTSR1) to be hypermethylated in large NTs. Quantitative bisulfite pyrosequencing revealed that NTSR1 is frequently methylated in colorectal tumors, with large NTs exhibiting the highest methylation levels. The higher NTSR1 methylation levels were associated with better prognoses. By contrast, NTSR1 copy number gains were most frequent among small ITs. Methylation of NTSR1 was associated with the gene's silencing in CRC cell lines, whereas ectopic expression of NTSR1 promoted proliferation and invasion by CRC cells. Analysis of primary tumors composed of adenomatous and malignant portions revealed that NTSR1 is frequently methylated in the adenomatous portion, while methylation levels are generally lower in the cancerous portions. These results suggest that NTSR1 methylation is associated with lateral and noninvasive growth of colorectal tumors, while low levels of methylation may contribute to the malignant potential through activation of NTSR1. Our data also indicate that NTSR1 methylation may be a prognostic biomarker in CRC.

Transanal endoscopic surgery: past, present and future

Transanal endoscopic surgery is a safe, established technique to remove lesions in the rectum via the anus. This article reviews its evolution, approaches, indications and evidence for its role in treating benign rectal polyps. The future of transanal endoscopic surgery in rectal cancer and inflammatory bowel disease is also explored.

Endoscopic submucosal dissection for laterally spreading tumors in the rectum ≥40 mm

BACKGROUND

Endoscopic submucosal dissection (ESD) has been developed to allow en bloc resection of early neoplasia of the gastrointestinal tract, including colorectal tumors. The aim of the present study was to evaluate the safety and efficacy of ESD for laterally spreading tumors (LSTs) in the rectum with diameters of 40 mm or more.

METHODS

Between January 2010 and October 2014, 35 patients with a total of 36 LSTs of the rectum measuring ≥40 mm were included in this study. Clinical and pathological characteristics and clinical outcomes were examined and analyzed.

RESULTS

The mean operating time was 125.8 ± 61.4 min, and the mean size of the tumors was 59.4 ± 19.8 mm. The rate of en bloc resection and en bloc R0 resection were 91.7 % (33/36) and 88.9 % (32/36), respectively. Perforation occurred in three patients (8.6 %) and was managed conservatively. Postoperative bleeding occurred in one patient (2.9 %) and was treated by endoscopic hemostasis. Excluding five patients, who either underwent additional surgery (n = 1) or were lost to follow-up (n = 4), two patients in our cohort (6.7 %) presented with recurrence of a small adenoma. The remaining patients (n = 28) were free of recurrence during a mean follow-up period of 18.7 ± 4.2 months (range 12-43 months).

CONCLUSIONS

Our results indicated that ESD is an effective and safe therapeutic option with high curative rates for LSTs in the rectum ≥40 mm. To prove its long-term efficacy, a large multicenter prospective study is required.

iTRAQ-Based Proteomics Screen identifies LIPOCALIN-2 (LCN-2) as a potential biomarker for colonic lateral-spreading tumors

The improvement and implementation of a colonoscopy technique has led to increased detection of laterally spreading tumors (LSTs), which are presumed to constitute an aggressive type of colonic neoplasm. Early diagnosis and treatment of LSTs is clinically challenging. To overcome this problem, we employed iTRAQ to identify LST-specific protein biomarkers potentially involved in LST progression. In this study, we identified 2,001 differentially expressed proteins in LSTs using iTRAQ-based proteomics technology. Lipocalin-2 (LCN-2) was the most up-regulated protein. LSTs expression levels of LCN-2 and matrix metallopeptidase-9 (MMP-9) showed positive correlation with worse pathological grading, and up-regulation of these proteins in LSTs was also reflected in serum. Furthermore, LCN-2 protein overexpression was positively correlated with MMP-9 protein up-regulation in the tumor tissue and serum of LST patients (former r_s = 0.631, P = 0.000; latter r_s = 0.815, P = 0.000). Our results suggest that LCN-2 constitutes a potential biomarker for LST disease progression and might be a novel therapeutic target in LSTs.

Management of T1 colorectal cancers after endoscopic treatment based on the risk stratification of lymph node metastasis

BACKGROUND AND AIM

Recent advances in endoscopic technology have allowed many T1 colorectal carcinomas to be resected endoscopically with negative margins. However, the criteria for curative endoscopic resection remain unclear. We aimed to identify risk factors for nodal metastasis in T1 carcinoma patients and hence establish the indication for additional surgery with lymph node dissection.

METHODS

Initial or additional surgery with nodal dissection was performed in 653 T1 carcinoma cases. Clinicopathological factors were retrospectively analyzed with respect to nodal metastasis. The status of the muscularis mucosae (MM grade) was defined as grade 1 (maintenance) or grade 2 (fragmentation or disappearance). The lesions were then stratified based on the risk of nodal metastasis.

RESULTS

Muscularis mucosae grade was associated with nodal metastasis (P = 0.026), and no patients with MM grade 1 lesions had nodal metastasis. Significant risk factors for nodal metastasis in patients with MM grade 2 lesions were attribution of women (P = 0.006), lymphovascular infiltration (P < 0.001), tumor budding (P = 0.045), and poorly differentiated adenocarcinoma or mucinous carcinoma (P = 0.007). Nodal metastasis occurred in 1.06% of lesions without any of these pathological factors, but in 10.3% and 20.1% of lesions with at least one factor in male and female patients, respectively. There was good inter-observer agreement for MM grade evaluation, with a kappa value of 0.67.

CONCLUSIONS

Stratification using MM grade, pathological factors, and patient sex provided more appropriate indication for additional surgery with lymph node dissection after endoscopic treatment for T1 colorectal carcinomas.