The Munich Polypectomy Study (MUPS): prospective analysis of complications and risk factors in 4000 colonic snare polypectomies

Evaluation of autofluorescence colonoscopy for the detection and diagnosis of colonic polyps

BACKGROUND

Colorectal cancer is the second most common cause of death in the United Kingdom. Most cancers are believed to arise within preexisting adenomas. Although colorectal adenomas have a clear neoplastic potential, hyperplastic polyps do not. It, therefore, would be helpful to be able to differentiate between different polyps at a colonoscopy. Autofluorescence (AF) endoscopy has been developed to enhance conventional white light (WL) endoscopy in the diagnosis of GI lesions.

OBJECTIVE

The aim of the present study was to evaluate whether AF colonoscopy can facilitate endoscopic detection and differentiation of colorectal polyps.

DESIGN

Patients were invited to attend for colonic assessment with both AF and WL endoscopy. AF readings, pictures, and biopsy specimens were taken of any visible pathology and of any high AF areas.

SETTING

Gartnavel General Hospital, Glasgow, U.K.

PATIENTS

A total of 107 patients were assessed.

INTERVENTION

Each patient was assessed with AF and WL colonoscopy.

MAIN OUTCOME MEASUREMENTS

An AF intensity ratio (AIR) was calculated for each polyp (ratio of direct polyp AF reading/background rectal AF activity).

RESULTS

A total of 75 polyps were detected: 54 adenomatous and 21 hyperplastic polyps. Colorectal adenomas had a significantly higher AIR compared with hyperplastic polyps (median, interquartile range): adenoma (3.54, 2.54-5.00] versus hyperplastic (1.60, 1.30-2.24); P = .0001). When using an AIR with the empirically cutoff value of 2.3, AF endoscopy had a sensitivity of 85% and a specificity of 81% at distinguishing adenomatous polyps from hyperplastic polyps.

CONCLUSIONS

AF colonoscopy may be a valuable tool for the visual distinction between adenomatous and hyperplastic polyps.

Review and evaluation of methods correcting for population stratification with a focus on underlying statistical principles

When two or more populations have been separated by geographic or cultural boundaries for many generations, drift, spontaneous mutations, differential selection pressures and other factors may lead to allele frequency differences among populations. If these 'parental' populations subsequently come together and begin inter-mating, disequilibrium among linked markers may span a greater genetic distance than it typically does among populations under panmixia [see glossary]. This extended disequilibrium can make association studies highly effective and more economical than disequilibrium mapping in panmictic populations since less marker loci are needed to detect regions of the genome that harbor phenotype-influencing loci. However, under some circumstances, this process of intermating (as well as other processes) can produce disequilibrium between pairs of unlinked loci and thus create the possibility of confounding or spurious associations due to this population stratification. Accordingly, researchers are advised to employ valid statistical tests for linkage disequilibrium mapping allowing conduct of genetic association studies that control for such confounding. Many recent papers have addressed this need. We provide a comprehensive review of advances made in recent years in correcting for population stratification and then evaluate and synthesize these methods based on statistical principles such as (1) randomization, (2) conditioning on sufficient statistics, and (3) identifying whether the method is based on testing the genotype-phenotype covariance (conditional upon familial information) and/or testing departures of the marginal distribution from the expected genotypic frequencies.

[Conventional colonoscopy]

In the last 40 years colonoscopy has been the gold standard in diagnosis of conditions affecting the large intestine. We see its main disadvantages in the necessity for intestinal preparation and in the pain not infrequently experienced by patients who are not sedated. Widespread use of sedation has made it possible to improve patient acceptance in recent years. Complications of colonoscopy are rare, and even the removal of large polyps is regarded as a safe procedure. One of the main problems of colonoscopy is that a large number of far from trivial polyps--up to 20% in the literature--are overlooked. New developments, such as higher resolution videochips and chromoendoscopy, lead to a better diagnostic yield, especially of flat lesions. The rapidly developing sector of interventional colonoscopy in particular will ensure that colonoscopy continues to have an important place in the management of illnesses affecting the large intestine.

A novel endoscopic suturing technique using a specially designed so-called "8-ring" in combination with resolution clips (with videos)

BACKGROUND

Although EMR has been proven to be a safe procedure, the risk of hemorrhage and perforation increases with the size of the resected lesion. To overcome such complications, we previously reported a technique using an endoloop and metal clips to close large mucosal defects after EMR. This procedure, however, requires a 2-channel colonoscope, which is not always available.

OBJECTIVES

Our purpose was to demonstrate the feasibility of mucosal defect closure by using a conventional single-channel colonoscope, a specially designed figure-of-8-shaped stainless steel ring (8-ring) and resolution clips.

DESIGN

Pilot study.

SETTING

Private outpatient clinic.

PATIENTS

A total of 10 patients with 10 lesions underwent this procedure for closure after EMR.

INTERVENTION

After EMR, a Resolution clip (Boston Scientific, Natick, Mass) was placed through 1 hole of the 8-ring and then attached to normal mucosa near 1 side of the resection site. Another resolution clip was inserted through the remaining hole of the device and clipped in the normal mucosa on the other side, thus providing complete closure. To strengthen the closure, conventional endoclips were also placed.

MAIN OUTCOME MEASUREMENTS

Technical feasibility of endoscopic closure of the mucosal defect after EMR and complications associated with endoscopic procedures.

RESULTS

Mean size of resected lesion was 16.3 mm. All the defects were successfully closed without any complication such as delayed bleeding or perforation.

LIMITATIONS

Further study is needed to examine the maximum size of defects that can be closed with this method.

CONCLUSIONS

Defects after EMR can be treated successfully with this simple technique.

Work and resources needed for endoscopic resection of large sessile colorectal polyps

BACKGROUND & AIMS

Large sessile colon polyps often are referred for surgical resection, even when amenable to endoscopic resection. The aim of this study was to describe the resource use of endoscopic resection of large sessile colon polyps compared with small polyps with respect to physician time and equipment use.

METHODS

Retrospectively, procedure time, medication use, and equipment use were recorded for 184 consecutive patients with sessile colorectal polyps 2 cm or larger in size and for 184 consecutive control patients with only sessile polyps less than 2 cm in size or pedunculated polyps.

RESULTS

The mean duration of colonoscopy in patients with large sessile colon polyps averaged 51.4 (SD, 25.6) minutes compared with 20.0 (SD, 8.6) minutes for the control group (P < .0001). The large-polyp group required much more equipment to complete the polypectomy (eg, injection catheters and cautery probes) (P < .0001).

CONCLUSIONS

Our results indicate that the costs of endoscopic large sessile adenoma resection in physician work and equipment are substantially greater than the costs of resection of small adenomas. These costs may be a deterrent to endoscopic resection of large sessile adenomas and may warrant increased reimbursement for those procedures, particularly if predictions that colonoscopic procedures will become more complex in the future are realized.

Conventional colonoscopy: Technique, indications, limits

Colonoscopy has long been the gold standard for the diagnosis of colonic diseases. Recently, with the advent of CT colonografy, new alternatives seem to appear on the horizon, which seem to finally overcome some of colonoscopy's drawbacks like procedure related pain and discomfort during the examination. Polyp miss rate and the fact that not always the caecum can be reached are also the basis of debate. This article gives an overview about current technique, indications and limitations of diagnostic colonoscopy as well as a potential prospect for the future, discussing novel imaging technologies ranging from magnification endoscopy to virtual histopathology.

Endoscopic interventions in the small bowel using double balloon enteroscopy: feasibility and limitations

BACKGROUND

Double-balloon enteroscopy (DBE) is a new endoscopic tool that not only allows diagnostic workup of small bowel diseases, but also makes it possible to carry out therapeutic interventions. However, for a variety of reasons, endoscopic therapy appears to be more difficult to carry out deep in the small bowel than in the upper or lower gastrointestinal tract.

AIM

The purpose of this study was to evaluate the acute technical success and acute complication rate of DBE.

PATIENTS

Between June 2003 and July 2006, 353 patients (152 women, 201 men; mean age 60.3 +/- 17.1 yr) with suspected or known small bowel disease underwent 635 consecutive DBE procedures. The majority of the patients were suffering from midgastrointestinal bleeding (N = 210, 60%). The overall diagnostic yield was 75% (265/353) for relevant lesions in the small bowel. The overall therapeutic yield was 67% (236/353).

METHODS

Endoscopic therapy was performed in 59% of these patients (139/236). All therapeutic interventions were done in an inpatient manner. The majority of the procedures were carried out with the patients under conscious sedation (N = 130, 73%); sedation with propofol was administered in 37 (20.8%) and with a combination of propofol and meperidine in 11 (6.2%) investigations.

RESULTS

A total of 178 therapeutic procedures was carried out. A median of 270 cm of the small bowel was visualized using the oral route and a median of 150 cm using the anal route. The investigation time averaged 78 +/- 30 minutes. The endoscopic treatments included argon plasma coagulation (APC, 102 treatment sessions), injection therapy (N = 2), a combination of APC and injection (N = 6), polypectomies (N = 46), dilation therapy (N = 18), and foreign-body extraction (N = 3). In 6/178 cases (3.4%), polypectomy (N = 2), dilation (N = 3), and implantation of a self-expanding metal stent (N = 1) could not be performed successfully for technical or anatomical reasons. Severe treatment-associated complications occurred in six of the 178 therapeutic procedures (3.4%) and 4/139 patients (2.9%), consisting of bleeding (N = 2) and perforation (N = 3) during and after polypectomy of large polyps (>3 cm in size), as well as one case of segmental enteritis after APC.

CONCLUSIONS

Endoscopic therapeutic interventions can be performed safely even in the more difficult conditions of the small bowel in the majority of patients. Polypectomy of large polyps appears to be the procedure associated with the highest risk.

Colonoscopic polypectomy: a critical review of recent literature

Colonoscopic polypectomy continues to be a major activity of gastrointestinal endoscopists, based upon the belief that ridding the colon of polyps prevents colon cancer. We review recent literature bearing on this assumption, emphasizing the benefits and limitations of colonoscopy for screening and surveillance of polyps. CT colonography has developed as an alternative or adjunct to colonoscopy but has not surpassed it in accuracy or therapeutic potential. Other recent technologic developments, such as magnification and chromoendoscopy, are reviewed, and an attempt is made to put them in perspective.