An evaluation of colorectal endoscopic mucosal resection using high-magnification chromoscopic colonoscopy: a prospective study of 1000 colonoscopies

Incomplete resection of colorectal polyps of 4-20 mm in size when using a cold snare, and its associated factors

BACKGROUND : Cold snare polypectomy (CSP) is increasingly used for polypectomy and is recommended as the first-line modality for small (< 10 mm) polyps. This study aimed to evaluate incomplete resection rates (IRRs) when using CSP for colorectal polyps of 4-20 mm. METHODS : Adults (45-80 years) undergoing screening, surveillance, or diagnostic colonoscopy and CSP by one of nine endoscopists were included. The primary outcome was the IRR for colorectal polyps of 4-20 mm, defined as the presence of polyp tissue in marginal biopsies after resection of serrated polyps or adenomas. Secondary outcomes included the IRR for serrated polyps, ease of resection, and complications. RESULTS:  413 patients were included (mean age 63; 48 % women) and 182 polyps sized 4-20 mm were detected and removed by CSP. CSP required conversion to hot snare resection in < 1 % of polyps of < 10 mm and 44 % of polyps sized 10-20 mm. The IRRs for polyps < 10 mm and ≥ 10 mm were 18 % and 21 %. The IRR was higher for serrated polyps (26 %) compared with adenomas (16 %). The IRR was higher for flat (IIa) polyps (odds ratio [OR] 2.9, 95 %CI 1.1-7.4); and when resection was judged as difficult (OR 4.2, 95 %CI 1.5-12.1), piecemeal resection was performed (OR 6.6, 95 %CI 2.0-22.0), or visible residual polyp was present after the initial resection (OR 5.4, 95 %CI 2.0-14.9). Polyp location, use of a dedicated cold snare, and submucosal injection were not associated with incomplete resection. Intraprocedural bleeding requiring endoscopic intervention occurred in 4.7 %. CONCLUSIONS : CSP for polyps of 4-9 mm is safe and feasible; however, for lesions ≥ 10 mm, CSP failure occurs frequently, and the IRR remains high even after technical success. Incomplete resection was associated with flat polyps, visual residual polyp, piecemeal resection, and difficult polypectomies.

Antibacterial Activity of T22, a Specific Peptidic Ligand of the Tumoral Marker CXCR4

CXCR4 is a cytokine receptor used by HIV during cell attachment and infection. Overexpressed in the cancer stem cells of more than 20 human neoplasias, CXCR4 is a convenient antitumoral drug target. T22 is a polyphemusin-derived peptide and an effective CXCR4 ligand. Its highly selective CXCR4 binding can be exploited as an agent for the cell-targeted delivery and internalization of associated antitumor drugs. Sharing chemical and structural traits with antimicrobial peptides (AMPs), the capability of T22 as an antibacterial agent remains unexplored. Here, we have detected T22-associated antimicrobial activity and biofilm formation inhibition over Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, in a spectrum broader than the reference AMP GWH1. In contrast to GWH1, T22 shows neither cytotoxicity over mammalian cells nor hemolytic activity and is active when displayed on protein-only nanoparticles through genetic fusion. Under the pushing need for novel antimicrobial agents, the discovery of T22 as an AMP is particularly appealing, not only as its mere addition to the expanding catalogue of antibacterial drugs. The recognized clinical uses of T22 might allow its combined and multivalent application in complex clinical conditions, such as colorectal cancer, that might benefit from the synchronous destruction of cancer stem cells and local bacterial biofilms.

Therapeutic Upper Gastrointestinal Endoscopy in Pediatric Gastroenterology

This paper seeks to give a broad overview of pediatric upper gastrointestinal (GI) pathologies that we are now able to treat endoscopically, acquired or congenital, and we hope this delivers the reader an impression of what is increasingly available to pediatric endoscopists and their patients.

Rates of Incomplete Resection of 1- to 20-mm Colorectal Polyps: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Incomplete resection of neoplastic colorectal polyps can result in postcolonoscopy colorectal cancer. We performed a systematic review and meta-analysis to determine the incomplete resection rate (IRR) of colorectal polyps and associated factors.

METHODS

We searched MEDLINE, EMBASE, EBM Reviews, and CINAHL to identify full-text articles that reported IRRs of polyps 1 to 20 mm, published until March 2019. Exclusion criteria were studies of inflammatory bowel disease cohorts, referrals for difficult polypectomy, polyp sizes larger than 20 mm, and endoscopic submucosal resection and/or dissection as polypectomy approaches. IRRs were calculated based on findings from biopsies taken at polypectomy sites or assessments of margins of resected polyps. The primary outcome was IRR for snare removal of polyps 1 to 20 mm. Secondary outcomes included IRR for polyps 1 to 10 mm and 10 to 20 mm, IRR for hot and cold snare removal of polyps 1 to 10 mm and 10 to 20 mm, IRR of snare removal with or without submucosal injection, and IRR for forceps and cold snare removal of polyps 1 to 5 mm.

RESULTS

We identified 6148 reports and used 32 studies, with a total of 9282 polyps, in our quantitative analysis. The IRR for snare removal of polyps 1 to 20 mm was 13.8% (95% confidence interval [CI] 10.3-17.3; 13 studies, 5128 polypectomies). IRRs were 15.9% for snare removal of polyps 1 to 10 mm (95% CI 9.6-22.1; 9 studies, 2531 polypectomies) and 20.8% for snare removal of polyps 10 to 20 mm (95% CI 12.9-28.8; 6 studies, 412 polypectomies). The IRR for hot snare removal of polyps 1 to 10 mm was 14.2% (95% CI 5.2-23.2) vs 17.3% for cold snare polypectomy (95% CI 14.3‒20.3). The IRR for forceps removal of polyps 1 to 5 mm was 9.9% (95% CI 7.1-13.0) vs 4.4% for snare polypectomy (95% CI 2.9-6.1).

CONCLUSIONS

In a systematic review and meta-analysis, we found that colorectal polyps 1 to 20 mm are frequently incompletely resected, and that risk increases for polyps 10 mm or larger. There is no difference in IRRs of cold vs hot snares for polyps 1 to 10 mm. Snare polypectomy should be used over forceps for polyps 1 to 5 mm.

Dye-based chromoendoscopy following polypectomy reduces incomplete polyp resection

Background and study aims  The completeness of a polyp resection is an important determinant of quality in colonoscopy, and may reduce incidence of interval cancers. Incomplete resection rates (IRR) vary widely and range from 6.5 % to 22.7 %. Residual disease is more likely with larger polyps, for sessile serrated adenomas, and with more proximal lesions. Chromoendoscopy is increasingly employed in lesion detection. The aims of this study were to assess local IRR, and to determine whether chromoendoscopy could correctly identify residual disease post polypectomy. Patients and methods  This was a prospective study examining post polypectomy sites. Chromoendoscopy (0.13 % indigo carmine) was applied to resection bases to identify residual disease. Targeted base biopsies were taken from identified residual disease (positive group) or random base biopsies were taken when a clear base was visualised (negative group). Overall rates of incomplete resection were documented. Reported rates post chromoendoscopy and actual histological rates were documented and compared. Results  A total of 102 polyps were identified for inclusion, of which 15 % (n = 16) were excluded. Resection quality was evaluated in 86 polyps of 61 patients (female n = 33 54 %; mean Age 62.3 years). Polyps were mainly removed by cold snare (n = 71, 82.5 %). Most polyps (n = 58, 67 %) measured between 5 to 10 mm. Polyps were largely located in the right colon (n = 57, 66 %). Overall histological residual disease occurred in 17 /86 (19.6 %). Chromoendoscopy correctly identified residual disease in 13 of 17 bases (76.5 %). Only four of /86 (4.6 %) of polyp bases were missclassified post-chromoendoscopy (odds ratio 0.284 (95 % CI 0.0857-0.9409), P  = 0.03). Conclusion  Indigo carmine chromoendoscopy improves early detection of residual disease post polypectomy, reducing incomplete resection rates.

EMR is superior to rectal suction biopsy for analysis of enteric ganglia in constipation and dysmotility

BACKGROUND AND AIMS

Patients with chronic constipation or motility disorders may be referred for rectal suction biopsy (RSB) to rule out Hirschsprung's disease (HD). RSB may not be successful beyond infancy because of the increased thickness of the rectal mucosa. EMR could improve the diagnostic yield for HD when compared with traditional RSB because larger and deeper samples are acquired for analysis.

METHODS

In this prospective, single-center study, patients referred for RSB were offered enrollment for concurrent EMR. Specimens were analyzed pathologically for size, submucosal ganglionic tissue, and acetylcholinesterase or calretinin staining. Biopsy results were compared with transit studies, anorectal manometry, and constipation severity through validated questionnaires.

RESULTS

Seventeen patients (2 male, 15 female; mean age, 35.8 years; range, 22-61 years) were enrolled in the study from 2008 to 2014. All patients underwent anorectal manometry (88% with anorectal dysfunction, 68% with outlet obstruction) and transit studies (41% with delayed transit). There were no reports of adverse events from the RSB and EMR procedures. The RSB sample volumes were significantly lower than the EMR sample volumes (0.023 cm³ vs 0.26 cm³, P = .001). There was diagnostic tissue for submucosal visualization by RSB in 53% (9/17) of cases compared with 100% (17/17) with EMR (P = .003). No cases of HD were diagnosed by RSB; one patient had rare ganglions observed by EMR.

CONCLUSIONS

EMR provides greater tissue volume and can improve the characterization of ganglion cells in rectal tissue compared with RSB in patients with moderate to severe constipation with suspected HD.

Endoscopic Approach for Superficial Colorectal Neoplasms

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in males and the second in females, with an estimated 1.4 million cases and 693,900 deaths in 2012. Colonoscopy is the cornerstone for the detection and prevention of CRC. In addition, endoscopic treatment for CRC at an early stage can effectively improve patients' quality of life and cure rate.

SUMMARY

This review focuses on endoscopic approaches, including white light endoscopy, chromoendoscopy, magnifying endoscopy and therapeutic endoscopy, for the evaluation and treatment of superficial colorectal neoplasms.

KEY MESSAGE

Understanding the preoperative evaluation, indications and techniques of endoscopic mucosal resection/endoscopic submucosal dissection as well as postoperative surveillance for superficial colorectal neoplasms is critical for providing appropriate management to the patients.

PRACTICAL IMPLICATIONS

Endoscopic therapy, a method preserving organ function and improving quality of life, is a widely applied microinvasive treatment for superficial colorectal neoplasms. This review describes the basics and developments of endoscopic approaches and may facilitate daily practice for superficial colorectal neoplasms.

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.

Probe-based confocal laser endomicroscopy for evaluating the submucosal invasion of colorectal neoplasms

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) is a novel method for in vivo histological analysis of colorectal neoplasm mucosa, which provides meaningful information for the development of adequate therapeutic strategies. However, the in vivo histology of colorectal neoplasm submucosa has not been studied. We assessed the feasibility and safety of pCLE for evaluating colorectal submucosa, and identified and validated diagnostic criteria for submucosal carcinoma infiltration.

METHODS

From March to July 2014, 83 pCLE videos of 51 lesions in 31 patients who underwent scheduled colonoscopic procedures for the removal of colorectal neoplasms were acquired consecutively. During the procedures, pCLE videos of the lesions and biopsy samples for histopathological analysis were acquired. Final histopathological results were used as the gold standard.

RESULTS

Based on the confocal pattern, we classified colorectal submucosa findings as negative (superficial submucosa, deep submucosa, and submucosa with fibrosis) or indicative of carcinoma infiltration. Dark and irregular cell nests with irregular cell architecture and little or no mucin were seen in submucosal carcinoma infiltration. Based on rates of correlation with pathological findings, the sensitivity, specificity, and accuracy of the classification of submucosal carcinoma infiltration by two observers were 91.7, 86.8, and 88.0 %, respectively. In addition, the results showed good interobserver agreement for the detection of submucosal carcinoma infiltration (κ = 0.757, standard error = 0.102). No adverse events occurred during the procedures.

CONCLUSIONS

Submucosa assessment by pCLE is feasible and safe. pCLE is useful for the differentiation of normal submucosa from carcinoma infiltration, particularly when infiltration is accompanied by severe fibrosis. Large-scale prospective studies are needed to further evaluate the clinical impact of the use of pCLE during endoscopy.

Large Colorectal Lesions: Evaluation and Management

In the last years, a distinctive interest has been raised on large polypoid and non-polypoid colorectal tumors, and specially on flat neoplastic lesions ≥20 mm tending to grow laterally, the so called laterally spreading tumors (LST). Real or virtual chromoendoscopy, endoscopic ultrasound or magnetic resonance should be considered for the estimation of submucosal invasion of these neoplasms. Lesions suitable for endoscopic resection are those confined to the mucosa or selected cases with submucosal invasion ≤1000 μm. Polypectomy or endoscopic mucosal resection remain a first-line therapy for large colorectal neoplasms, whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory.

Antimicrobial prophylaxis in patients with colorectal lesions undergoing endoscopic resection

AIM: To investigate the effect of prophylaxis with antibiotics on clinical adverse events in patients who underwent endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) for colorectal lesions.

METHODS: From June 2011 to December 2013, a total of 428 patients were enrolled into the study, of which 214 patients admitted to hospital underwent EMR or ESD procedures. These patients were randomized to an antibiotic group, in which patients were given cefuroxime 1.5 g iv half an hour before and 6 h after surgery respectively, and a control group, in which patients were not given any antibiotic. A further 214 outpatients with small polyps treated by polypectomy were compared with controls that were matched by age and gender, and operations were performed as outpatient surgery. Recorded patient parameters were demographics, characteristics of lesions and treatment modality, and the size of the wound area. The primary outcome measures were clinical adverse events, including abdominal pain, diarrhea, hemotachezia, and fever. Secondary outcome measures were white blood cell count, C-reactive protein and blood culture. Additionlly, the relationship between the size of the wound area and clinical adverse events was analyzed.

RESULTS: A total of 409 patients were enrolled in this study, with 107 patients in the control group, 107 patients in the antibiotic group, and another 195 cases in the follow-up outpatient group. The patients’ demographic characteristics, including age, gender, characteristics of lesions, treatment modality, and the size of the wound area were similar between the 2 groups. The rates of adverse events in the antibiotic group were significantly lower than in the control group: abdominal pain (2.8% vs 14.9%, P < 0.01), diarrhea (2.0% vs 9.3%, P < 0.05), and fever (0.9% vs 8.4%, P < 0.05) respectively. The levels of inflammatory markers also decreased significantly in the antibiotic group compared with the control group: leukocytosis (2.0% vs 11.2%, P < 0.01), and C-reactive protein (2.0% vs 10.7%, P < 0.05). Additionally, clinical adverse events were related to the size of the surgical wound area. When the surgical wound area was larger than 10 mm × 10 mm, there were more clinical adverse events.

CONCLUSION: Clinical adverse events are not uncommon after EMR or ESD procedures. Prophylactic antibiotics can reduce the incidence of clinical adverse events. This should be further explored.

Tools for polyp histology prediction

Although removal of adenomatous polyps has been shown to decrease the risk of colon cancer, distal hyperplastic polyps are thought to not have malignant potential. Most polyps detected during colonoscopy are diminutive (≤ 5 mm) and rarely harbor advanced histology, such as high-grade dysplasia or cancer. Therefore, predicting histology in real-time during colonoscopy can potentially decrease the enormous expenditure that ensues from universal histopathologic evaluation of polyps, and several novel imaging technologies have been developed and tested over the past decade for this purpose. Of these different technologies, electronic chromoendoscopy seems to strike a fair balance between accuracy, feasibility, and cost.

Serrated and non-serrated precursor lesions of colorectal cancer

Although often viewed as a single disease, colorectal cancer more accurately represents a family of diseases with different precursor lesions. Conventional (tubular, tubulovillous and villous) adenomas are the most common neoplastic lesions occurring in the large intestine. They have adenomatous polyposis coli (APC) mutations and arise from dysplastic aberrant crypt foci, initially as polyclonal lesions. In sporadic tumours, neoplastic progression follows the traditional pathway (chromosomal instability pathway), resulting in CpG island methylator phenotype (CIMP)-negative, microsatellite-stable (MSS), BRAF and KRAS wild-type cancers. Germline mutations in the APC gene lead to familial adenomatous polyposis. Conventional adenomas are also the precursors of Lynch syndrome-associated microsatellite-instable (MSI-high) cancers. Sessile serrated adenoma/polyp (SSA/P) is the principal precursor lesion of the serrated pathway, in which BRAF mutation can lead to colorectal cancer with MSI-high CIMP-high or MSS CIMP-high phenotype. SSA/Ps have been associated with synchronous and metachronous invasive adenocarcinomas as well as so-called interval carcinomas. Serrated polyposis is rare but most likely underdiagnosed. Affected individuals bear an increased but unspecified risk for the development of colorectal cancer; close endoscopic surveillance is warranted. Traditional serrated adenomas (TSAs) are much less common than the other serrated lesions. Cancers originating from TSAs may show KRAS mutation with a CIMP-high MSS phenotype.

Endoscopic techniques for improving colorectal adenoma detection: Recent progress

Colorectal cancer (CRC) is one of the most common malignant neoplasms worldwide and develops mostly from precancerous lesions such as colorectal adenomas. Therefore, early detection and resection of colorectal adenomas is key to preventing CRC. At present, colonoscopy is acknowledged as the gold standard for the diagnosis and treatment of colorectal lesions; however, conventional colonoscopy is still associated with a certain rate of missed lesions. It is reported that the missed detection rate is 6% when adenomas are more than 1 cm, 13% for adenomas 6-9 mm, and 27% for adenomas less than 5 mm. The missed detection rate for right colonic adenomas is higher than that for left colonic adenomas. The missed diagnosis of colorectal adenomas or malignant tumors invariably increases surgical rate and mortality. Currently, great efforts have been made to improve the detection rate of colorectal adenomas. This paper will briefly review recent advances in endoscopic techniques for improving the detection rate of colorectal adenomas.

The efficacy of cap-assisted colonoscopy in polyp detection and cecal intubation: a meta-analysis of randomized controlled trials

OBJECTIVES

The role of cap-assisted colonoscopy (CAC) in polyp detection and cecal intubation is unclear. We conducted a meta-analysis to compare the efficacy of CAC vs. standard colonoscopy (SC).

METHODS

Publications in English and non-English literatures (OVID, MEDLINE, and EMBASE) and abstracts in major international conferences were searched for controlled trials comparing CAC and SC. Outcome measures included the proportion of patients with polyps or adenomas detected, cecal intubation rate, cecal intubation time, and total colonoscopy time. The statistical heterogeneity of trials was examined and the effects were pooled by random-effects model. The risk of bias was evaluated by the assessment tool from the Cochrane Handbook. Subgroup analyses were performed for possible clinical and methodological heterogeneities.

RESULTS

From 2,358 citations, 16 randomized controlled clinical trials were included consisting of 8,991 subjects (CAC: 4,501; SC: 4,490). Mean age of subjects was 61.0 years old and 60% were males. CAC detected a higher proportion of patients with polyp(s) (relative risk (RR): 1.08; 95% confidence interval (CI): 1.00-1.17) and reduced the cecal intubation time (mean difference: -0.64 min; 95% CI: -1.19 to -0.10). Cecal intubation rate (RR: 1.00; 95% CI: 0.99-1.02) and total colonoscopy time (mean difference: -0.97 min; 95% CI: -2.33 to 0.40) were comparable between the two groups. In subgroup analyses, a short cap (≤4 mm) was associated with improved polyp detection, whereas a long cap (≥7 mm) was associated with a shorter cecal intubation time.

CONCLUSIONS

CAC demonstrated marginal benefit over SC for polyp detection and shortened the cecal intubation time.

Approach to rectal cancer surgery

Rectal cancer is a distinct subset of colorectal cancer where specialized disease-specific management of the primary tumor is required. There have been significant developments in rectal cancer surgery at all stages of disease in particular the introduction of local excision strategies for preinvasive and early cancers, standardized total mesorectal excision for resectable cancers incorporating preoperative short- or long-course chemoradiation to the multimodality sequencing of treatment. Laparoscopic surgery is also increasingly being adopted as the standard rectal cancer surgery approach following expertise of colorectal surgeons in minimally invasive surgery gained from laparoscopic colon resections. In locally advanced and metastatic disease, combining chemoradiation with radical surgery may achieve total eradication of disease and disease control in the pelvis. Evidence for resection of metastases to the liver and lung have been extensively reported in the literature. The role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal metastases is showing promise in achieving locoregional control of peritoneal dissemination. This paper summarizes the recent developments in approaches to rectal cancer surgery at all these time points of the disease natural history.

Endoscopic mucosal resection in colorectal lesion: a safe and effective procedure even in lesions larger than 2 cm and in carcinomas

CONTEXT: Endoscopic mucosal resection is a minimally invasive technique used in the treatment of colorectal neoplasms, including early carcinomas of different size and morphology. OBJECTIVES: To evaluate procedure safety, efficacy, outcomes, and recurrence rate in endoscopic mucosal resection of colorectal lesions. METHODS: A total of 172 lesions in 156 patients were analyzed between May 2003 and May 2009. All lesions showed pit pattern suggestive of neoplasia (Kudo types III-V) at high-magnification chromocolonoscopy with indigo carmine. The lesions were evaluated for macroscopic classification, size, location, and histopathology. Lesions 20 mm or smaller were resected en bloc and lesions larger than 20 mm were removed using the piecemeal technique. Complications and recurrence were analyzed. Patients were followed up for 18 months. RESULTS: There were 83 (48.2%) superficial lesions, 57 (33.1%) depressed lesions, 44 (25.6%) laterally spreading tumors, and 45 (26.2%) protruding lesions. Mean lesion size was 11.5 mm ± 9.6 mm (2 mm-60 mm). Patients' mean age was 61.6 ± 12.5 years (34-93 years). Regarding lesion site, 24 (14.0%) lesions were located in the rectum, 68 (39.5%) in the left colon, and 80 (46.5%) in the right colon (transverse, ascending, and cecum). There were 167 (97.1%) neoplasms: 142 (82.5%) adenomatous lesions, 24 (14.0%) intramucosal carcinomas, and 1 (0.6%) invasive carcinoma. En bloc resection was performed in 158 (91.9%) cases and piecemeal resection in 14 (8.1%). Bleeding occurred in 5 (2.9%) cases. Recurrence was observed in 4.1% (5/122) of cases and was associated with lesions larger than 20 mm (P<0.01), piecemeal resection (P<0.01), advanced neoplasm (P = 0.01), and carcinoma compared to adenoma (P = 0.04). CONCLUSIONS: Endoscopic mucosal resection of colorectal lesions is a safe and effective procedure, with low complication and local recurrence rates. Recurrence is associated with lesions larger than 20 mm and carcinomas.

[Non-serrated precursor lesions of colorectal tumours]

Non-serrated precursor lesions of colorectal tumours include conventional adenomas (tubular, tubulovillous and villous), inflammatory bowel disease-associated dysplasia (intraepithelial neoplasia), and hamartoma-associated dysplasia. This short review summarizes the current literature on the adenoma-carcinoma sequence, focusing on colonic stem cells and functional crypt organization, patterns of stem cell division, niche succession and clonal conversion in the formation of a monocryptal adenoma. The process of clonal interaction between neighboring crypts as well as the development of large monoclonal adenomas from small polyclonal precursor lesions is discussed in detail. Finally, the molecular pathogenesis as well as the clinical significance of inflammatory bowel disease- and hamartoma-associated carcinogenesis is addressed.

Emergency percutaneous needle decompression for tension pneumoperitoneum

Background

Tension pneumoperitoneum as a complication of iatrogenic bowel perforation during endoscopy is a dramatic condition in which intraperitoneal air under pressure causes hemodynamic and ventilatory compromise. Like tension pneumothorax, urgent intervention is required. Immediate surgical decompression though is not always possible due to the limitations of the preclinical management and sometimes to capacity constraints of medical staff and equipment in the clinic.

Methods

This is a retrospective analysis of cases of pneumoperitoneum and tension pneumoperitoneum due to iatrogenic bowel perforation. All patients admitted to our surgical department between January 2005 and October 2010 were included. Tension pneumoperitoneum was diagnosed in those patients presenting signs of hemodynamic and ventilatory compromise in addition to abdominal distension.

Results

Between January 2005 and October 2010 eleven patients with iatrogenic bowel perforation were admitted to our surgical department. The mean time between perforation and admission was 36 ± 14 hrs (range 30 min - 130 hrs), between ER admission and begin of the operation 3 hrs and 15 min ± 47 min (range 60 min - 9 hrs). Three out of eleven patients had clinical signs of tension pneumoperitoneum. In those patients emergency percutaneous needle decompression was performed with a 16G venous catheter. This improved significantly the patients' condition (stabilization of vital signs, reducing jugular vein congestion), bridging the time to the start of the operation.

Conclusions

Hemodynamical and respiratory compromise in addition to abdominal distension shortly after endoscopy are strongly suggestive of tension pneumoperitoneum due to iatrogenic bowel perforation. This is a rare but life threatening condition and it can be managed in a preclinical and clinical setting with emergency percutaneous needle decompression like tension pneumothorax. Emergency percutaneous decompression is no definitive treatment, only a method to bridge the time gap to definitive surgical repair.

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) in 2011, a Western perspective

Endoscopic mucosal resection (EMR) has become the standard of care for removal of large flat and sessile neoplastic lesions of the GI tract. Recently, endoscopic submucosal dissection (ESD) was introduced in Japan as an alternative technique, which allows en bloc resection of large lesions. The applications of EMR and ESD are expanding and many Western endoscopists are adopting these techniques. Paris classification and Kudo pit pattern classification allows prediction of the depth of invasion of early neoplastic lesions and thus, avoids resection of lesions invading the deep submucosa which have higher rates of lymphatic spread. ESD of early stomach cancer is the standard of care in Japan. Recent published reports from Western countries showed comparable results for ESD of early gastric cancers to those done in Japan. Recently, EMR combined with ablation has been used frequently in Western countries for treatment of high-grade dysplasia in early adenocarcinoma of the esophagus. Although ESD of early neoplastic lesions of the esophagus is technically difficult, few promising reports were published proving the feasibility of this technique in the West. ESD has been shown to achieve higher en bloc resection and lower rates of tumour recurrence in removal of lateral spreading colonic polyps. A hybrid technique of circumferential submucosal incision followed by en bloc EMR has been used for removal of large colonic lesions in some Western endoscopy centres. In Western countries, training for ESD is challenging given the lack of training in the relatively easier early gastric cancer lesions. Animal model training combined with observing experts in ESD could be an alternative for Western endoscopists. Inspite of obstacles, ESD applications are continuing to grow in Western countries.

Diagnosis of depth of invasion for early colorectal cancer using magnifying colonoscopy

BACKGROUND AND AIMS

Early colorectal cancer (CRC) with submucosal deep (s.m.-d.) invasion should not be treated with endoscopic mucosal resection due to the higher incidence of lymph-node metastasis. It is, therefore, clinically important to accurately diagnose s.m.-d. lesions before treatment.

METHODS

We analyzed the endoscopic features, including pit patterns, of early CRC with s.m.-d. invasion observed using magnifying colonoscopy. We retrospectively investigated 379 cases of early CRC. Lesions were divided into three macroscopic subtypes (pedunculated type, sessile type and superficial type) based on endoscopic findings. Eight endoscopic factors were evaluated retrospectively for association with s.m. invasion and then compared to histopathological findings.

RESULTS

The superficial type had a significantly higher frequency of s.m.-d. invasion (52.4% [77/147] vs 24.6% [14/57] and 39.4% [69/175], P-value < 0.05, respectively, for pedunculated and sessile types). Based on multivariate analysis, an independent risk factor for s.m.-d. invasion was the existence of an invasive pit pattern in sessile and superficial types (odds ratios of 52.74 and 209.67, respectively). Fullness was also an independent risk factor for s.m.-d. invasion in the superficial type (odds ratio = 9.25). There were no independent risk factors for s.m.-d. invasion in the pedunculated type.

CONCLUSION

High magnification pit pattern diagnosis proved to be useful for predicting s.m.-d. invasion in sessile and superficial types although it was not as helpful with the pedunculated type.

Colonoscopic perforation: Incidence, risk factors, management and outcome

This review discusses the incidence, risk factors, management and outcome of colonoscopic perforation (CP). The incidence of CP ranges from 0.016% to 0.2% following diagnostic colonoscopies and could be up to 5% following some colonoscopic interventions. The perforations are frequently related to therapeutic colonoscopies and are associated with patients of advanced age or with multiple comorbidities. Management of CP is mainly based on patients’ clinical grounds and their underlying colorectal diseases. Current therapeutic approaches include conservative management (bowel rest plus the administration of broad-spectrum antibiotics), endoscopic management, and operative management (open or laparoscopic approach). The applications of each treatment are discussed. Overall outcomes of patients with CP are also addressed.

Prediction of histology and invasive depth of colorectal neoplasia based on morphology of surface depression using magnifying chromocolonoscopy

BACKGROUND AND STUDY AIMS

Estimation of histology and depth of invasion in early colorectal neoplasia is essential for patient treatment. We therefore conducted a prospective study to examine whether the morphology of depression area contained at the surface of colorectal neoplasia can be used for predicting the histology and invasive depth.

METHODS

A series of 228 consecutive patients with 296 colorectal lesions were studied. All lesions were evaluated by magnifying chromocolonoscopy. Surface depression contained in the lesions was noted and the depressive morphology was further divided into two subgroups of type I and type II. All of the lesions were resected endoscopically or surgically and examined histologically for comparison.

RESULTS

A total of 296 lesions were evaluated, of which 66 (22.3%) contained an area of central depression, including 43 in nonpolypoid (flat and depressed) lesions (66%) and 23 in polypoid (10%). The overall accuracy of depressive morphology for distinction between low-grade dysplasia and high-grade dysplasia/invasive cancer, and between m-sm1 and sm2-sm3 was 86.4% and 84.8%, respectively.

CONCLUSIONS

Depression was predominantly contained in nonpolypoid colorectal neoplasia. Morphology of depression observed by magnifying chromocolonoscopy could be used as a complementary method to assess the degree of atypia and invasive depth in colorectal neoplasia.

Structural enhancement and video endoscopy: results of a large prospective comparative study

INTRODUCTION

The structural-enhancement (SE) function electronically improves the video-endoscopic signal of Olympus processors (EXERA CV-160 or greater), enabling an increase in relief that may help in the detection of flat or ulcerated and raised lesions, especially those of small size. We assessed the diagnostic impact of this technique in the screening of lesions during basic video colonoscopy.

METHODS

Maximum-level SE was programmed into processors on alternate weeks, and endoscopy dates were planned by an assistant unaware of the SE schedule, thus ensuring randomization. The endoscopists-senior practitioners with 3-29 years of digestive endoscopy practice-were informed of the experiment >3 weeks before it began and were not told about it again either before or during the study. This was to ensure that endoscopy examinations were performed without over-awareness of the technical conditions. GIF-100 to -160 Olympus endoscopes were used.

RESULTS

During the study, 606 patients underwent upper digestive video-endoscopy, 305 with and 301 without the use of the SE function. Of 645 patients who underwent video colonoscopy, 593 were included in the study and 52 were excluded due to poor cleansing (8%); of those included, 330 were analyzed with and 263 without the SE function. We observed no differences in the detection of lesions (small or large) by either upper digestive endoscopy or video colonoscopy.

CONCLUSION

This is the first study comparing video-endoscopy diagnosis with or without SE during upper digestive endoscopy and colonoscopy. The SE function available on Olympus video-endoscopy processors had no impact on the detection of lesions, not even on those of very small size.

Lymphatic vessel invasion detected by monoclonal antibody D2-40 as a predictor of lymph node metastasis in T1 colorectal cancer

OBJECTIVE

When selecting patients who are at high risk for lymph node metastasis, the detection of lymphatic vessel invasion (LVI) is important. We investigated LVI detected by D2-40 staining as a predictor of lymph node metastasis in T1 colorectal cancer.

MATERIALS AND METHODS

Clinicopathological factors including LVI were investigated in 136 patients who underwent colectomy with lymph node dissection for T1 colorectal cancer. We used immunostaining with monoclonal antibody D2-40 to detect LVI.

RESULTS

Lymph node metastases were found in 18 patients (13.2%), and LVI were detected in 45 (33%); lymph node metastasis was more frequently observed in LVI-positive groups (13/45 vs 5/91, p < 0.001). Both univariate and multivariate analyses revealed that LVI detected by D2-40 and a poorly differentiated histology at the invasion front were independent risk factors of lymph node metastasis.

CONCLUSION

LVI detected by D2-40 is important for the prediction of lymph node metastasis.

Salvage endoscopic submucosal dissection for residual or local recurrent intraepithelial neoplasia in the colorectum: a prospective analysis

OBJECTIVE

A prospective technical feasibility study of cap assisted ESD for 'curative intent' in patients with residual or local neoplastic recurrence following EMR. Primary end points were second stage R0 resection rate, safety and recurrence.

METHOD

Salvage ESD was performed using the Olympus GIF-XQ240 gastroscope and KD-630L insulation tipped knife. Thirty-day mortality, re-admission rates, complications and histological resection status were collected prospectively up to 9 months following index resection.

RESULTS

Thirty patients met eligibility criteria. Index R0 resection was achieved in 25/30 (83%) lesions. One patient underwent surgical excision with a second receiving a curative second stage dissection. Ninety-six per cent (29/30) patients were discharged within 24 h of the procedure with a 0% 30-day mortality and re-admission rate. Bleeding occurred in 5/30 (16%) treated successfully with endoluminal haemostasis. There were no perforations. Overall 'cure' rates at short-term follow-up [median 6/12 (range; 3-18)] was 96%.

CONCLUSION

This novel application of ESD for first line 'salvage' therapy in treating residual or locally recurrent neoplastic disease may be a safe, minimally invasive and cost effective alternative to direct surgical resection in a select patient cohort.

Low frequency of bacteremia after an endoscopic resection for large colorectal tumors in spite of extensive submucosal exposure

BACKGROUND

During an EMR or endoscopic submucosal dissection (ESD) for colorectal tumors, an injection needle catheter is passed through the contaminated endoscopic channel and may directly inoculate bacteria into the blood stream during submucosal injection. In addition, extensively exposed submucosa, especially with an ESD, directly contacts colonic luminal bacteria after the procedure, which may increase the risk of bacteremia. However, the incidence of bacteremia after an EMR or ESD for colorectal tumors has not been reported.

OBJECTIVE

To evaluate the frequency of bacteremia associated with an EMR or ESD for colon lesions.

DESIGN

A prospective study.

PATIENTS

A total of 40 patients who underwent a conventional EMR (n = 30), an EMR after circumferential pre-cutting (n = 3), or ESD (n = 7) for colorectal tumors.

INTERVENTIONS AND MAIN OUTCOME MEASUREMENTS

Blood cultures were obtained immediately before, 5 minutes after, and 30 minutes after the procedure. Patients were closely monitored for 24 hours after the procedure to detect the development of infectious complications.

RESULTS

Blood cultures at baseline and 5 minutes after the procedure were all negative. However, a blood culture at 30 minutes after the procedure showed a positive result in 1 of 40 patients (2.5%). This patient underwent a conventional EMR, and the isolated microorganism was coagulase-negative Staphylococcus, which might be regarded as a contaminant. None of the 40 patients showed any signs or symptoms associated with infection.

LIMITATION

The small sample size.

CONCLUSIONS

An EMR, or even an ESD, for colon lesions may be considered a low-risk procedure for infectious complications that does not warrant prophylactic administration of antibiotics.

Chromoscopic endomicroscopy: in vivo cellular resolution imaging of the colorectum

Advances in imaging technology and engineering have now permitted functional integration of a confocal endomicroscope into the distal tip of a conventional video colonoscope enabling imaging of the surface epithelium and the underlying lamina propria during ongoing video endoscopy. For the first time, the endoscopist is now able to resolve the surface and subsurface mucosa at cellular resolution in vivo and in real time. A new era in endoscopic imaging has therefore begun - histoendoscopy. In addition to providing a high-accuracy in vivo optical biopsy tool for the differentiation between benign hyperplasia, intra-epithelial neoplasia and carcinoma in sporadic cohorts, endomicroscopy with targeted biopsies has now been shown to increase the yield of intra-epithelial neoplasia complicating ulcerative colitis. Furthermore, recent data examining endomicroscopic molecular ex vivo imaging using anti-CD44v6 antibody has identified aberrant crypt foci based on their surface molecular expression. Receptor overexpression in vivo in humans may, in the near future, be exploited for the diagnosis of inflammation, neoplasia and in predicting targeted molecular therapy. Endomicroscopy will be key to this immuno-imaging interface. Within the present review, we discuss the current clinical evidence in support of confocal endomicroscopy and explore the new diagnostic possibilities for this technology.

Endoscopic mucosal resection of colonic lesions: current applications and future prospects

The introduction of submucosal fluid injection has remarkably extended the range of endoscopically resectable polyps. The limiting factor for endoscopic resection is not polyp size, but polyp depth. Endoscopic ultrasound is a useful adjunctive diagnostic tool to assess the depth of invasion. The success of are section ultimately depends on pathologic confirmation of a benign nature of this lesion or of a cancer limited to the mucosa. Selected well-differentiated cancers without lymphovascular invasion of the superficial submucosa can be successfully resected endoscopically.

Achieving R0 resection in the colorectum using endoscopic submucosal dissection

BACKGROUND

Endoscopic mucosal resection is established for the removal of non-invasive colorectal tumours smaller than 20 mm but is unsatisfactory for larger lesions. Endoscopic submucosal dissection (ESD) enables en bloc resection of lesions larger than 20 mm. A UK-based prospective feasibility study of ESD for colorectal tumours was undertaken; primary endpoints were R0 resection, safety and recurrence.

METHODS

Patients with Paris 0-II adenomas or laterally spreading tumours (LSTs) greater than 20 mm in diameter were enrolled between November 2004 and August 2006. Lesions were assessed by chromoscopy and high-frequency ultrasonography. Dysplasia, resection status, 30-day complication rates and recurrence after ESD were recorded.

RESULTS

ESD was performed in 42 of 56 identified patients; en bloc resection was possible in 33. Fourteen Paris 0-II lesions and 28 LSTs were identified; 40 were dysplastic adenomas and two adenocarcinomas. R0 resection was achieved in 31 patients (74 per cent). The 30-day mortality rate was 0 per cent. Perforation occurred in one patient and uncomplicated bleeding in five. The 6-month cure rate was 81 per cent (34 of 42 patients).

CONCLUSION

High cure rates are achievable using ESD for Paris 0-II adenomas and LSTs greater than 20 mm in diameter, with R0 resection possible in most patients. ESD is feasible throughout the colorectum with no increase in complication rates. It should be considered for selected Tim/T1 N0 colorectal lesions.

Magnifying colonoscopy: interobserver agreement in the assessment of colonic pit patterns and its correlation with histopathological findings

BACKGROUND AND STUDY AIMS

Magnifying colonoscopy (MC) is recognized as an aid to the differential diagnosis between neoplastic and nonneoplastic lesions. This study evaluated interobserver agreement of experienced endoscopists in the assessment of colonic pit patterns through the Kudo's classification and correlated morphological aspects with histopathological findings.

MATERIALS AND METHODS

A total of 213 magnification chromoendoscopic pictures of colonic lesions were collected from 161 consecutive patients and presented to three independent observers who expressed opinion about predominant pit pattern. All lesions were excised and sent for histopathological study.

RESULTS

Kappa statistics showed that the general agreement index with respect to the aspects of the pits was good among the three observers (0.561). Regarding prediction of histopathology according to the pit pattern diagnosis, overall accuracy was 84%, sensitivity was 91.4%, specificity was 67.2%, positive predictive value was 86.6%, and negative predictive value was 79.3%.

CONCLUSION

Although the interobserver reproducibility of the colonic pit pattern is good for experienced endoscopists, MC must not be used to replace the histopathological analysis, since it does not differentiate with the necessary safety neoplastic from nonneoplastic lesions.

Confocal endomicroscopy in ulcerative colitis: differentiating dysplasia-associated lesional mass and adenoma-like mass

BACKGROUND & AIMS

The management of dysplasia-associated lesional mass (DALM) and adenoma-like mass (ALM) in chronic ulcerative colitis (CUC) differs radically, involving total pan-proctocolectomy vs endoscopic resection and surveillance. Such lesions cannot be reliably differentiated using conventional colonoscopy. Confocal laser scanning imaging enables in vivo surface and subsurface cellular resolution imaging during ongoing video endoscopy. The aim of this study was to prospectively assess the clinical applicability and predictive power of the Pentax EC3870K endomicroscope for the in vivo differentiation of ALM and DALM in CUC during ongoing videocolonoscopy.

METHODS

Patients were recruited who had a diagnosis of ALM or DALM within the previous 16 weeks. Confocal laser endomicroscopic (CLE) imaging of the circumscribed lesion and 4 adjacent mucosal segments was performed. Targeted biopsy with and without tissue sampling with endoscopic mucosal resection was performed and compared with conventional histopathology as the gold standard.

RESULTS

Thirty-six patients with 36 lesions fulfilled the study entry criteria. Using modified Mainz criteria for the in vivo diagnosis of ALM and DALM, the kappa coefficient of agreement between CLE and histopathologic evaluation was 0.91, and accuracy was 97% (95% confidence interval = 86%-99%).

CONCLUSIONS

This is the first study addressing the novel application of the Pentax EC3870K endomicroscopy system for the in vivo differentiation of ALM and DALM during ongoing video colonoscopy in CUC. We have shown that ALM and DALM can be differentiated with a high overall accuracy, enabling the safe selection of patients suitable for endoluminal resection versus immediate referral for pan-proctocolectomy.

Novel clinical in vivo roles for indigo carmine: high-magnification chromoscopic colonoscopy

Since the adenoma-carcinoma sequence was first proposed by Morson in the 1970s, it has become widely accepted that detection and subsequent removal of polypoid adenomas from the colon reduces the incidence of colorectal cancer. These adenomas are relatively easy to detect by conventional colonoscopy; however, large population studies have shown that despite resection of polypoid adenomas, interval colorectal cancers still occurred. Recent advances in technology have given today's endoscopists access to high-resolution and high-magnification scopes, which has facilitated detection of flat and depressed colorectal lesions. Current data suggest that such morphologically distinct lesions may account for up to 30% of all colorectal adenomas. Furthermore, flat and depressed lesions of the large bowel may confer greater malignant potential compared to polypoid adenomas. The majority of flat lesions show only subtle changes by conventional colonoscopy, but the use of stains, such as indigocarmine, in addition to magnification colonoscopy can enhance their detection significantly. In this paper, we discuss the rationale for detecting flat colorectal lesions. We explore the use of high-magnification colonoscopy and chromoendoscopy, with particular reference to the application of indigocarmine, in this patient group. We also discuss the novel therapeutic techniques now available for these lesions.

The role of chromoendoscopy in the surveillance of the duodenum of patients with familial adenomatous polyposis

Adenomas of the duodenum have been described in patients with familial adenomatous polyposis (FAP). Patients with FAP are at high risk for the development of periampullary cancer. The aim of our study was to evaluate if endoscopic visualization of small polyps, often overlooked at standard endoscopic examination, was improved by chromoendoscopy. Ten patients with FAP and previous colectomy underwent upper gastrointestinal endoscopy. Two skilled endoscopists were involved for each endoscopy. Evaluation of number and diameter of polyps was made before and after staining. After staining we detected a larger number of duodenal polyps than found at the standard endoscopic examination, the difference being statistically significant. This result seems to suggest that chromoendoscopy may improve diagnostic yield of endoscopy. Further studies are needed to suggest the best surveillance program and the appropriate therapeutic modality for these patients.

Detection and treatment of early flat and depressed colorectal cancer using high-magnification chromoscopic colonoscopy: a change in paradigm for Western endoscopists?

Japanese researchers reported flat and depressed colorectal lesions in the 1980s. Such lesions were thought irrelevant to Western populations and described as "Phantom" or "Akitas" carcinoma. Many depressed neoplasms arise through the de novo pathogenic sequence and demonstrate early invasive characteristics. All investigators report difficulties in identifying flat and depressed lesions using conventional colonoscopy. Failure to detect and treat such lesions may be responsible for the current shortfalls in secondary colorectal cancer prevention. Given the introduction of colorectal cancer screening programs in the United Kingdom, Europe, and the United States, it is essential to re-evaluate the significance of flat lesions as applicable to Western cohorts and explore the safety and efficacy of new endoscopic technology and interventional therapeutics.

Intraoperative fluoroscopy vs. intraoperative laparoscopic ultrasonography for early colorectal cancer localization in laparoscopic surgery

BACKGROUND

In colorectal cancer (CRC) surgery, precise tumor localization is important for oncologically correct surgery and adequate tumor and lymph node resection margins. During laparoscopic surgery it is difficult to localize early CRC. The aim of this study was to compare the usefulness of two tumor localization techniques; intraoperative fluoroscopy and intraoperative laparoscopic ultrasonography.

METHODS

Seventeen patients with CRC necessitating preoperative marking were alternately allocated to either the fluoroscopy (F) group (n = 8) or the laparoscopic ultrasonography (LU) group (n = 9). A three-step technique was used. At first lesions were localized preoperatively by metallic clips that were colonoscopically applied proximally and distally to the tumor site. Second, computed tomography (CT) colonography was taken to obtain preoperative staging. The location of the metallic clips was confirmed by CT colonography, preoperatively. Third, in the F group, intraoperative fluoroscopy was performed to localize the applied clips. In the LU group, the applied clips were detected from the serosal aspect of the colon using intraoperative laparoscopic ultrasonography.

RESULTS

In all patients, colonoscopic metallic clips were successfully applied and preoperative CT colonography correctly detected the location of the tumor. Marking sites were detected precisely using intraoperative fluoroscopy or intraoperative laparoscopic ultrasonography in all cases, without complications. The mean detection time was 15.8 minutes in the F group and 7.0 minutes in the LU group (p = 0.005). In the LU group, two cases were technically difficult because of interruption of the ultrasound by intestinal air.

CONCLUSIONS

Both intraoperative fluoroscopy and intraoperative laparoscopic ultrasonography are safe and accurate techniques for intraoperative localization of early CRC. With regard to detection time, intraoperative laparoscopic ultrasonography is superior to intraoperative fluoroscopy. However, when there is a massive amount of intestinal air, intraoperative laparoscopic ultrasonography is cumbersome in localizing the lesion. Computed tomography colonography is useful for preoperative tumor localization and might be effective for shortening detection time during surgery.

Colonic adenocarcinomas: near-infrared microcatheter imaging of smart probes for early detection--study in mice

PURPOSE

To prospectively evaluate the ability of micro-fiberoptic catheters, which simultaneously record white light and near-infrared (NIR) images, to reveal colonic neoplasms after the intravenous administration of activatable "smart" probes that increase in NIR fluorescence subsequent to protease activation.

MATERIALS AND METHODS

The institutional animal care committee approved all animal experiments. CT26 tumor cells were orthotopically implanted into the descending colon of C57BL6/J mice (n=10). Thirteen days later, mice intravenously received either 2 nmol of a protease-sensing probe that had cathepsin B as a major activator (n=5) or saline (control animals [n=5]). One day later, animals were noninvasively examined to the point of the splenic flexure by using microcatheter imaging. Excised colons were subsequently evaluated with epifluorescence imaging, histologic examination, and cathepsin B immunohistochemistry. Student t test was used for statistical analysis, with P<.05 considered to indicate a significant difference.

RESULTS

Results with fiberoptic imaging demonstrated that all tumors were visible with the protease-activatable probe, even when they were not readily apparent at white light imaging. A target-to-background ratio (TBR) of 8.86 for tumor to adjacent normal mucosa was achieved in the NIR channel after probe administration (P=.001), whereas white light images resulted in a TBR of 1.14 (P>.5) based on luminosity. The tumoral NIR fluorescence intensity was more than 30-fold greater in probe-injected animals than in control animals, indicating that essentially all of the signal recorded in lesions was from activatable probe administration. Results of immunohistochemistry confirmed cathepsin B overexpression in the tumor compared with adjacent mucosa.

CONCLUSION

The use of NIR imaging microcatheters combined with protease-activatable smart probes results in a beacon effect that highlights tumors with high TBRs; this technique thus may be a potentially useful adjunct to white light colonoscopy in the future.

Novel colorectal endoscopic in vivo imaging and resection practice: a short practice guide for interventional endoscopists

Colorectal cancer remains a leading cause of cancer death in the UK. With the advent of screening programmes and developing techniques designed to treat and stage colorectal neoplasia, there is increasing pressure on the colonoscopist to keep up to date with the latest practices in this area. This review looks at the basic principles behind endoscopic mucosal resection and forward to the potential endoscopic tools, including high-magnification chromoscopic colonoscopy, high-frequency miniprobe ultrasound and confocal laser scanning endomicroscopic colonoscopy, that may soon become part of routine colorectal cancer management.

Olympus Lucera high-resolution vascular ectasia mapping in combination with the type V crypt pattern for the invasive depth estimation and nodal disease estimation in Paris type II colorectal cancers: a comparative prospective analysis to 20 MHz ultrasound

INTRODUCTION

Flat and depressed neoplastic lesions of the colorectum [Paris type (PT) 0-II] localized to the superficial submucosal (sm) layer can be managed using endoscopic mucosal resection. Successful endoluminal management can be enhanced using endoscopic or ultrasound tools that help predict the degree of sm invasion. Previous studies addressing invasive depth estimation using high-magnification chromoscopic colonoscopy showed a low specificity for deep sm layer 3 invasion with miniprobe ultrasound demonstrating better nodal and T stage in vivo prediction. High-resolution vascular mapping of lesions can show microvascular superficial changes that may predict sm invasive disease.

AIMS

Vascular mapping in combination with high-magnification chromoscopic colonoscopy (HMCC) may provide an accurate tool for the invasive depth estimation of PT type II neoplastic lesions as compared with high frequency 20/12.5 MHz miniprobe ultrasound.

METHODS

Sixty-eight patients with a known diagnosis of PT II neoplasia were imaged using 3 "back to back" imaging modalities. Phase 1-vascular ectasia mapping; phase 2-HMCC with crypt analysis according to Nagata criteria; phase 3-12.5/20 MHz miniprobe ultrasound. Lesions predicted as T0/1/N0 were resected using endoscopic mucosal resection with the remaining referred for surgery. Each imaging modality was then compared with the resected histopathologic specimen used as the "gold standard."

RESULTS

N=68 lesions (19 sm1/13 sm2/36 sm3). Overall accuracy of Nagata criteria, Nagata criteria combined with vascular mapping, and ultrasound staging was 65%, 78%, and 94%, respectively (P<0.001) when observing the between phase differences. Fifty-two lesions were resected surgically. The prevalence of node positive disease was 16% (8/52) with the remaining 44/52 (84%) being confirmed pN0 at histopathology. The kappa coefficient of agreement between invasive depth estimation (using histopathology as the gold standard), Nagata stage, Nagata stage plus vascular ectasia mapping and ultrasound stage was 0.47, 0.65, and 0.9, respectively. A significant improvement in between phase differences was observed (P=0.001).

CONCLUSIONS

This is the first study to address the in vivo clinical utility of vascular mapping in combination with HMCC for the T and N staging of PT II neoplasia. Combination imaging may provide an adequate clinical tool for both T and N stage assessment in vivo and help stratify those patients at high risk for T2/N1 disease that may benefit from further high-frequency miniprobe ultrasound (HFUS) assessment and possible primary surgical excision. This is important in the clinical context, given the high overall costs of a second HFUS examination, limitation of HFUS resources, and safe selection of patients undergoing primary endoscopic resection versus surgical resection.

Flat elevated lesions of the colon and rectum: a spectrum of neoplastic and nonneoplastic entities

The aim of this prospective study is to establish the frequency and the type (neoplastic and nonneoplastic) lesions defined endoscopically as flat elevated lesion (FEL) in the colon and rectum, as well as to compare flat adenomas (FAs) to polypoid lesions of the same size with morphometric and immunohistochemical analysis. One hundred nineteen patients were studied through fibrocolonoscopy with chromoscopy (indigo carmine spray). All detected lesions (total of 195) were removed, and FELs measuring 10 mm or smaller were also selected. Using histopathologic criteria, they were divided in neoplastic (adenomas and carcinomas) and nonneoplastic ones. In neoplastic lesions, the following parameters were evaluated to compare FAs with polypoid lesions: morphometric studies with Index of Structural Atypia (ISA) and Stratification Index (SI), evaluation of cellular proliferation with label index of Ki-67, and expression of p53 protein. Of 195 lesions resected, only 33 (17%) met the endoscopic requirements for FELs. Twelve (36.4%) were neoplastic and 21 (63.6%) considered nonneoplastic. Among the FAs, there were a percentage of high-grade (severe dysplasia) significantly more frequent than observed in polypoid lesions (16.7% vs 2.6%). In addition, the SI, Ki-67 label index and p53 positivity were significantly higher in FAs. The ISA also reached significant differences between both groups of adenomas. Non-neoplastic FELs included different entities such as hyperplasic polyps, focuses of colitis, normal mucosa, and scars. The endoscopic elements analyzed were shared between nonneoplastic FELs and FAs. A central depression, when air was properly insufflated, considered typical in neoplastic lesions, was frequently observed in nonneoplastic lesions. Following the endoscopic criteria of FELs, nonneoplastic lesions predominated over the adenomatous lesions, demonstrating that FELs and FAs are not homologous terms. The frequency of high-grade dysplasia was significantly more elevated in the adenomatous FELs than in polypoid adenomas. The ISA, SI, p53 expression, and Ki-67 label index were helpful in differentiating adenomatous FELs from polypoid lesions. Flat elevated lesions selected by endoscopic criteria are, in fact, a heterogeneous population of lesions.

Optical adjuncts for enhanced colonoscopic diagnosis

Background

Optical techniques using previously unexploited properties of light interaction with tissue may be valuable in the detection, diagnosis and staging of colorectal neoplasia.

Methods

A Medline search (1990 to present) was conducted on optical diagnostics in the detection of colorectal neoplasia. The reference list of each identified article was reviewed for further relevant papers.

Results and conclusion

Chromoendoscopy is the only optical adjunct to colonoscopy that has been tested in large randomized clinical trials. It improves the detection of small and flat colorectal adenomas, and of neoplasia in chronic ulcerative colitis and hereditary non-polyposis colorectal cancer. All other techniques are the subject of ongoing research and the practicality of population screening with any of the methods has yet to be established. Optical techniques may, however, permit immediate clinical diagnosis, removing the need for histological analysis. They may also improve the diagnosis of early colonic neoplasia.