DIAGNOSIS OF COLONIC ADENOMAS BY NEW AUTOFLUORESCENCE IMAGING SYSTEM: A PILOT STUDY

Detection and removal of adenoma by colonoscopy is an important means of preventing cancer. Autofluorescence endoscopy can visualize flat or isochromatic tumor that was not detectable by white light endoscopy by the difference in tissue fluorescence properties. Recently, a new autofluorescence imaging system (AFI, Olympus Medical Systems) using a combination of autofluorescence and reflection imaging has been developed. The purpose of the present paper was to investigate its feasibility in detection of colonic adenoma in a clinical setting. A total of 64 patients were randomly assigned to AFI or white light groups, and the distal sigmoid colon and the rectum was observed under autofluorescence or white light followed by the other mode of observation by a different endoscopist. The diagnostic ability of each method for detection of neoplasms was compared in relation to the histology as a reference standard. Sensitivity and specificity of AFI for detection of neoplastic polyps was 84% and 60%, respectively, and were similar to those of white light colonoscopy: 90% and 64%. Conventional colonoscopy overlooked more flat lesions including one adenocarcinoma. AFI has the potential to detect more flat lesions but efficacy was unable to be demonstrated in the restricted population. Further investigations are needed to determine optimum usage.     

Can optical diagnosis of small colon polyps be accurate? Comparing standard scope without narrow banding to high definition scope with narrow banding

AIM: To study the accuracy of using high definition(HD) scope with narrow band imaging(NBI) vs standard white light colonoscope without NBI(ST), to predict the histology of the colon polyps, particularly those 1 cm.METHODS: A total of 147 African Americans patients who were referred to Howard University Hospital for screening or, diagnostic or follow up colonoscopy, during a 12-mo period in 2012 were prospectively recruited. Some patients had multiple polyps and total number of polyps was 179. Their colonoscopies were performed by 3 experienced endoscopists who determined the size and stated whether the polyps being removed were hyperplastic or adenomatous polyps using standard colonoscopes or high definition colonoscopes with NBI. The histopathologic diagnosis was reported by pathologists as part of routine care. RESULTS: Of participants in the study, 55(37%) were male and median(interquartile range) of age was 56(19-80). Demographic, clinical characteristics, past medical history of patients, and the data obtained by two instruments were not significantly different and two methods detected similar number of polyps. In ST scope 89% of polyps were 1 cm vs 87% in HD scope(P = 0.7). The ST scope had a positive predictive value(PPV) and positive likelihood ratio(PLR) of 86% and 4.0 for adenoma compared to 74% and 2.6 for HD scope. There was a trend of higher sensitivity for HD scope(68%) compare to ST scope(53%) with almost the same specificity. The ST scope had a PPV and PLR of 38% and 1.8 for hyperplastic polyp(HPP) compared to 42% and 2.2 for HD scope. The sensitivity and specificity of two instruments for HPP diagnosis were similar.CONCLUSION: Our results indicated that HD scope was more sensitive in diagnosis of adenoma than ST scope. Clinical diagnosis of HPP with either scope is less accurate compared to adenoma. Colonoscopy diagnosis is not yet fully matched with pathologic diagnosis of colon polyp. However with the advancement of both imaging and training, it may be possible to increase the sensitivity and specificity of the scopes and hence save money for eliminating time and the cost of Immunohistochemistry/pathology.     

Colonoscopic miss rates determined by direct comparison of colonoscopy with colon resection specimens

OBJECTIVES: Colonoscopy is an effective method for discovery of adenomas and for colon cancer screening and prevention. Studies evaluating back-to-back colonoscopies have estimated significant miss rates but are limited by the lack of a definitive gold standard. Our study evaluated the sensitivity of colonoscopy compared with examination of surgically resected colon as a gold standard. METHODS: This was a retrospective analysis of patients who had a portion of colon surgically removed and had lower endoscopy within 5 months. The focus of the review was not for the particular lesion for which the surgery was indicated but, rather, for the synchronous lesions in the portions of bowel that were removed. Sensitivity was determined by counting the number of lesions detected at colonoscopy compared with those found in the surgically resected segment. RESULTS: A total of 73 synchronous lesions were present in the resected segments of 156 patients. Colonoscopy detected 56 of 73 the lesions (sensitivity 76.7%: 95% CI = 67-86). Of the 17 missed lesions, 14 of 17 (82%, 95% CI = 64-100) were < 1-cm polyps. Endoscopy overlooked one 1-cm adenoma in the ascending colon. Two cancers were missed, both in the same patient in whom endoscopy detected a sigmoid cancer but missed synchronous lesions in the cecal and ascending colon. CONCLUSIONS: Colonoscopy is an effective method of finding cancers and polyps, but it is associated with significant miss rates for polyps <1 cm. The entire bowel should be carefully evaluated to exclude synchronous tumors in patients with known colorectal cancer. Further improvement of colonoscopic techniques and technologies is warranted.     

Colonic polyps diagnosis by conventional video colonoscopes and chromoscopy with indigo carmine dye solution

BACKGROUND: Magnification colonoscopy and contrast chromoscopy with indigo carmine dye solution have been used to differentiate neoplastic polyps (adenomas and adenocarcinomas) from non-neoplastic (hyperplastic, inflammatory, juvenile) in an attempt to obviate endoscopic polypectomy. On the other hand, little published information exists concerning conventional video colonoscopes and chromoscopy for polyp histology prediction. Aim - To assess usefullness of conventional video colonoscopes and contrast chromoscopy with indigo carmine solution for differential diagnosis of colon polyps. METHODS: In a routine colonoscopy series, we performed chromoscopy with conventional video colonoscopes before endoscopic excision of detected polyps. If a sulcus pattern was observed on the surface of the lesion, it was classified as neoplastic. Polyps were classified as non-neoplastic if no sulcus was detected on its surface. These observations were then compared with histology. RESULTS: In the study period (18 months), we detected 133 polyps in 53 patients. We were able to compare results of histology and chromoscopy in 126 lesions. The sensitivity, specificity, diagnostic accuracy, negative predictive value, and positive predictive value were 56,4%, 79,2%, 65,1%, 52,8%, and 81,5%, respectively. CONCLUSION: On the base of the presented data, we concluded that conventional video colonoscopes and contrast chromoscopy with indigo carmine solution is not a good technique for differential diagnosis of colon polyps.     

Findings on optical colonoscopy after positive CT colonography exam

BACKGROUND & AIMS:  The aim of this study is to evaluate the findings on optical colonoscopy (OC) after a positive CT colonography (CTC) exam and characterize the type of polyps seen on OC but not reported by CTC.
METHODS:  Over an 18-month period a total of 159 asymptomatic adults had polyps seen on computed tomography colonography examination and subsequently underwent planned therapeutic optical colonoscopy. The colonoscopists were aware of the findings on CT colonography prior to further evaluation of the colon. Characteristics of polyps and adenomas seen on subsequent optical colonoscopy but not seen or reported on CT colonography were examined.
RESULTS:  The adenoma miss rate for CT colonography overall was 18.9% (25/132) including 6.2% (4/65) for polyps >9 mm and 18.2% (8/44) for polyps 6–9 mm. Three of the adenomas >9 mm not seen on CTC were sessile, and two were found in patients with technically difficult CT colonography studies due to poor colonic distention. No adenomas with advanced pathology <6 mm were found on optical colonoscopy but not reported on CT colonography. False-positive CTC referral where no polyp was seen on colonoscopy was 5.0%.
CONCLUSIONS:  CT colonography has adenoma miss rates similar to miss rates historically found with optical colonoscopy, with most missed adenomas being <10 mm and sessile in shape.     

Motion - computerized tomographic colography is a better method for screening for polyps: arguments against the motion.

Computerized tomographic (CT) colography is an exciting technique whereby images of the colonic wall and lumen can be obtained without colonoscopy. It is not as good as conventional colonoscopy, however, because of both inherent and performance limitations. Among the former is the inability to visualize subtle mucosal lesions, such as alterations in colour or pliability. More importantly, CT colography is strictly a diagnostic technique, and does not allow biopsy or removal of polyps. The vigorous bowel preparation required for this procedure can be very unpleasant for the patient, and includes purgatives followed by distension of the colon with air. Unlike with colonoscopy, adherent stool can be difficult to distinguish radiologically from polyps or cancers; as a result, many patients require colonoscopy anyway. The major performance limitations of CT colography are poor sensitivity and specificity compared with conventional colonoscopy. Rectal lesions, flat adenomas and diminutive adenomas are especially difficult to detect, and false-positive results are also common. In addition, the procedure is expensive and less cost effective than colonoscopy. CT colography takes relatively little patient time, but a substantial amount of time is needed for the radiologist to interpret the images. Interobserver variability is high. For all of these reasons, CT colography cannot be recommended as a screening test for colorectal neoplasia.     

Clinicopathological characteristics of serrated polyps as precursors to colorectal cancer: Current status and management

Serrated polyps have long been thought to lack malignant potential in the human colorectum. However, identification of the serrated pathway to colorectal cancer based on molecular biology has improved our understanding of the pathogenesis of colorectal cancers. Accordingly, serrated polyps such as traditional serrated adenoma and sessile serrated adenoma/polyps (SSA/P) are now considered to be precursor lesions of the serrated pathway. Recently, serrated polyps were classified into three subtypes, consisting of hyperplastic polyp, SSA/P, and traditional serrated adenoma, according to the World Health Organization classification. It has been suggested that SSA/P in the proximal colon are a precursor lesion of pathogenesis of colorectal cancer and are characterized by BRAF mutation and a CpG island methylator phenotype with or without microsatellite instability. However, SSA/P is more challenging to detect by colonoscopy and is likely to account for some interval cancers, particularly in the proximal colon because it presents flat or sessile, isochroous appearance, and occasionally has a mucous cap. Furthermore, the possibility has been raised that pathologists misclassify SSA/P as hyperplastic polyp. It is important for gastroenterologists to recognize the endoscopic features of serrated polyps to facilitate their detection and removal and also to establish postpolypectomy surveillance guidelines. In this review, we discuss the recent classification of serrated polyps; the molecular characteristics of the serrated pathway; appropriate diagnostic methods using endoscopy, including a new image‐enhanced endoscopic technique; and management of these lesions.     

Computed tomographic colonography and conventional colonoscopy for colon diseases: a prospective, blinded study

OBJECTIVES: Computed tomographic (CT) colonography or virtual colonoscopy is a new diagnostic method for the colon and rectum, developed on the basis of spiral computed axial tomography and employing virtual reality technology. The aim of this study was to determine the sensitivity, specificity, and diagnostic accuracy of CT colonography compared with colonoscopy in a prospective, blinded study in one single institution in Italy. METHODS: Ninety-nine patients randomly selected among those attending the open-access endoscopy unit for diagnostic colonoscopy underwent colonoscopy and spiral CT. The images obtained were transmitted to generate the virtual colonoscopy pictures. A supervisor compared the results with the findings of conventional colonoscopy. RESULTS: CT colonography diagnosed seven of eight tumors, one being missed because the patient had been inadequately prepared. In 28 patients, CT colonography identified 26 polyps of 45 (57.8% sensitivity, 92.6% specificity, 86.7% positive predictive value), regardless of their size. The sensitivity in detecting colonic polyps was 31.8% (7/22) in the first 25 cases and 91.6% (11/12) in the last 20 patients. CT colonography missed one flat adenoma, some angioectasias and colonic lesions because of portal hypertension in one patient, Crohn's disease ulcers in two patients, and ulcerative colitis lesions in three. CONCLUSIONS: CT colonography shows poor sensitivity for identifying colonic polyps and does not always detect neoplastic lesions. Flat lesions are impossible to see by this method.     

The Miss Rate for Colorectal Adenoma Determined by Quality-Adjusted, Back-to-Back Colonoscopies

Background/Aims

Colonoscopy is considered to be the gold standard for detecting adenomatous polyps. Polyps are missed during colonoscopic examination at a rate that varies from 6% to 27%. The adenoma miss rate affects colonoscopic surveillance intervals and procedural quality. We aimed to assess the adenoma miss rate and the variables affecting the rate using same-day, quality-adjusted, back-to-back colonoscopies.

Methods

This prospective study was performed at a single institution and included 149 patients. Two consecutive same-day colonoscopies were performed by two experienced endoscopists. The adenoma miss rates and variables affecting the missed adenomas, including polyp characteristics and procedure times, were evaluated.

Results

The miss rates of polyps, adenomas, and advanced adenomas were 16.8%, 17%, and 5.4%, respectively. The smaller polyps and increased number of polyps detected during the first colonoscopy were more likely to be missed. A longer insertion time during the colonoscopy was correlated with an increased adenoma detection rate.

Conclusions

There was a significant miss rate in the detection of colonic adenomas even in quality-adjusted, back-to-back colonoscopies. The adenoma miss rate can be reduced with a sufficient observation time during colonoscopic insertion. The development of specific technological methods to reduce the adenoma miss rate is necessary.     

Expanding the view of a standard colonoscope with the Third Eye? Panoramic? cap

AIM: To evaluate a new imaging device for colonoscopy that adds two side viewing CMOS lenses, the Third Eye^® Panoramic™ cap.METHODS: In this prospective observational feasibility study, 33 patients, 18 male and 15 female, underwent routine screening, surveillance or diagnostic colonoscopy with the new Third Eye^® Panoramic™ cap clipped on to the distal tip of a high definition Fuji EC530-LS Slim Colonoscope^®. All procedures were performed at the New York Presbyterian-Queens Endoscopy unit by two experienced endoscopists (Rubin M and Kim SH). Main outcome measurements included evaluation of the image quality of the Third Eye^® Panoramic™ cap, adenoma detection rate, cecal intubation rate, withdrawal time and total procedure time.RESULTS: The Third Eye^® Panoramic™ cap enabled enhanced views without affecting the quality of the colonoscope’s image or its handling characteristics through the colon. Ileal intubation was accomplished in most cases, but was more challenging. The side view lenses detected polyps and diverticula hidden behind folds and in flexures not seen on the standard view. The side view lenses were easily cleaned utilizing an Endogator^® Irrigation Pump (Medivators, Minneapolis, MN, United States) by angling the scope tip against the mucosa while washing. The cecum was reached in all 33 patients. Mean cecal intubation time was 8.19 ± 2.17 min, mean withdrawal time was 10.15 ± 5.56 min and mean total procedure time was 20.31 ± 5.14 min. The overall adenoma detection rate was 44%.CONCLUSION: The Third Eye^® Panoramic™ cap enables wide view colonoscopy with enhanced visualization utilizing standard forward view colonoscopes.     

Does autofluorescence imaging videoendoscopy system improve the colonoscopic polyp detection rate?--a pilot study

OBJECTIVES: Colonoscopy is considered the gold standard for the detection of colorectal polyps; however, polyps can be missed with conventional white light (WL) colonoscopy. The aim of this pilot study was to evaluate whether a newly developed autofluorescence imaging (AFI) system can detect more colorectal polyps than WL.
METHODS: A modified back-to-back colonoscopy using AFI and WL was conducted for 167 patients in the right-sided colon including cecum, ascending and transverse colon by a single experienced colonoscopist. The patient was randomized to undergo the first colonoscopy with either AFI or WL (group A: AFI-WL, group B: WL-AFI). The time needed for both insertion and examination for withdrawal and all lesions detected in the right-sided colon were recorded.
RESULTS: Eighty-three patients were randomized to group A and 84 to group B. The total number of polyps detected by AFI and WL colonoscopy was 100 and 73, respectively. The miss rate for all polyps with AFI (30%) was significantly less than that with WL (49%) ( P = 0.01).
CONCLUSIONS: AFI detects more polyps in the right-sided colon compared to WL colonoscopy.     

Intraprocedural bowel cleansing with the Jet Prep cleansing system improves adenoma detection

AIM: To investigate the impact of Jet Prep cleansing on adenoma detection rates.METHODS: In this prospective,randomized,crossover trial,patients were blindly randomized to an intervention arm or a control arm.In accordance with the risk profile for the development of colorectal carcinoma,the study participants were divided into high-risk and low-risk groups.Individuals with just one criterion(age 70 years,adenoma in medical history,and first-degree relative with colorectal cancer) were regarded as high-risk patients.Bowel preparation was performed in a standardized manner one day before the procedure.Participants in the intervention arm underwent an initial colonoscopy with standard bowel cleansing using a 250-m L syringe followed by a second colonoscopy that included irrigation by the use of the Jet Prep cleansing system.The reverse sequence was used in the control arm.The study participants were divided into a high-risk group and a low-risk group according to their respective risk profiles for the development of colorectal carcinoma.RESULTS: A total of 64 patients(34 men and 30 women) were included in the study; 22 were included in the high-risk group.After randomization,30 patients were assigned to the control group(group A) and 34 to the intervention group(group B).The average Boston Bowel Preparation Scale score was 5.15 ± 2.04.The withdrawal time needed for the first step was significantly longer in group A using the Jet Prep system(9.41 ± 3.34 min) compared to group B(7.5 ± 1.92 min).A total of 163 polyps were discovered in 64 study participants who underwent both investigation steps.In group A,49.4% of the polyps were detected during the step of standard bowel cleansing while the miss rate constituted 50.7%.Group B underwent cleansing with the Jet Prep system during the first examination step,and as many as 73.9% of polyps were identified during this step.Thus,the miss rate in group B was a mere 26.1%(P 0.001).When considering only the right side of the colon,the miss rate in group A during the first examination was 60.6%,in contrast to a miss rate of 26.4% in group B(P 0.001).CONCLUSION: Jet Prep is recommended for use during colonoscopy because a better prepared bowel enables a better adenoma detection,particularly in the proximal colon.     

High-definition and filter-aided colonoscopy

New high-resolution colonoscopes and filter technologies are allowing us to visualize more lesions and better characterize lesions within the gastrointestinal tract. In light of recent findings that flat and serrated lesions are more likely to contain invasive cancer and that even small lesions (5-10 mm) may contain advanced histology, detecting these lesions earlier with improved optical technologies may help decrease the rate of interval cancers after colonoscopy. With the limited accuracy of white-light colonoscopy (59%-84%) in distinguishing non-neoplastic lesions from neoplastic lesions, these new technologies can help us improve our abilities to risk stratify patients and determine more precise surveillance intervals.     

Detectability of colorectal neoplastic lesions using a narrow‐band imaging system: A pilot study

Background and Aim: Flat and depressed colorectal neoplastic lesions can be difficult to identify using conventional colonoscopy techniques. Narrow‐band imaging (NBI) provides unique views especially of mucosal vascular network and helps in visualization of neoplasia by improving contrast. The aim of this study was to assess the feasibility of using NBI for colorectal neoplasia screening. Methods: Forty‐seven consecutive patients, who underwent high definition colonoscopy (HDC) screening examinations revealing neoplastic lesions, were enrolled in our prospective study. No biopsies or resections were performed during the initial HDC, but patients in whom lesions were detected underwent further colonoscopies using NBI, with the results of the first examination blinded from the colonoscopist. They then received appropriate treatment. We compared diagnostic detection rates of neoplastic lesions for HDC and NBI procedures using total number of all identified neoplastic lesions as reference standard. Results: Altogether, 153 lesions were detected and analyzed in 43 patients. Mean diagnostic extubation times were not significantly different (P = 0.18), but the total number of lesions detected by NBI was higher (134 vs 116; P = 0.02). Based on macroscopic type, flat lesions were identified more often by NBI (P = 0.04). As for lesion size, only flat lesions < 5 mm were detected more frequently (P = 0.046). Lesions in the right colon were identified more often by NBI (P = 0.02), but NBI missed two flat lesions ≥ 10 mm located there. Conclusions: Narrow band imaging colonoscopy may represent a significant improvement in the detection of flat and diminutive lesions, but a future multi‐center controlled trial should be conducted to fully evaluate efficacy for screening colonoscopies.     

Epidemiologic characteristics of the flat adenoma of muto

The flat adenoma is an endoscopically visible lesion that histologically consists of adenomatous change near the luminal surface of colonic tubules. We have described three families with hereditary colon cancer with later age of onset than familial adenomatous polyposis (FAP) and with multiple proximal colonic flat adenomas. These families have been linked to the FAP locus on chromosome 5. Our aim was to determine whether the flat adenoma is pathognomonic of this hereditary flat adenoma syndrome (HFAS) or merely an atypical or early tubular adenoma with occurrence in patients other than those from colon cancer-prone families. Methods: We prospectively examined a population referred for colonoscopy within a one-year period. During colonoscopy, flat adenomas were specifically sought and all lesions were removed endoscopically and evaluated histologically. Members of known hereditary colon cancer families were excluded. Results: One hundred forty-eight patients underwent colonoscopy (64 men and 84 women). Median age was 61 years. Fifty-seven patients had 157 polyps. One hundred thirty-six polyps were reviewed histologically. Thirty-five (23.6 percent) of the referred patients had adenomas, of whom twelve patients had only flat adenomas while six had both flat and other adenomas (18=12 percent of 148). The associations between flat adenoma occurrence and various predictors (sex, race, prior colonic neoplasms, family history of cancer, synchronous adenomas) were similar to those seen with other adenomas. Flat adenomas were found in nearly equal proportions of patients under or over age 61 years (11 percent and 13 percent, respectively). Other adenomas were significantly more common in the older group (6 percent vs.25 percent;P <0.002 by Fisher's exact test). Conclusion: In a referral practice, the flat adenoma has the same prevalence and associated risk factors as other adenomas, except for younger age of onset. Our data suggest that the flat adenoma represents an early stage of adenoma development that is manifested in a subset of patients from the general population and that, as an isolated event, does not provide a marker for a hereditary colon cancer-prone syndrome.Supported in part by NCI Grant 5 ROI CA-42705.     

170 degrees wide-angle colonoscope: effect on efficiency and miss rates

BACKGROUND: Small polyps are routinely missed during colonoscopy even with careful examination. AIM: To determine and compare endoscopic efficiency and polyp miss rate between a prototype 170 degrees wide-angle (WA) colonoscope and a standard (S) colonoscope. METHODS: Two consecutive same-day colonoscopies were performed in 50 patients with intact colons. The patients were randomized to undergo the first colonoscopy with either the prototype WA 170 degrees angle of view colonoscope or an S adult 140 degrees angle of view colonoscope. RESULTS: The mean time for insertion was 2.09 (1.09) min versus 2.53 (1.47) min (p= 0.002) for the WA colonoscope and the S colonoscope, respectively. Similarly, the mean time for examination during withdrawal was shorter with the WA colonoscope (4.98 (0.94) vs 5.74 (1.12) min; p < 0.0001). The mean insertion time for the second examination was shorter than the insertion time for the first examination, irrespective of the colonoscope (p= 0.006). However, the withdrawal times were not significantly different between the first and second examinations (p= 0.11). The miss rate for all polyps with the WA colonoscope (19%) was similar to the miss rate with the S colonoscope (27%; p= 0.19). The miss rates for adenomas with the WA (10/33; 30.3%) and the S scope (15/50; 30%) were similar (p= 0.98). CONCLUSIONS: The use of the WA colonoscope was associated with a reduction in insertion time to the cecum, as well as examination time during withdrawal. No evidence was found that the accuracy of the two colonoscopes differs.     

Quality monitoring in colonoscopy: Time to act

Colonoscopy is the gold standard test for colorectal cancer screening. The primary advantage of colonoscopy as opposed to other screening modalities is the ability to provide therapy by removal of precancerous lesions at the time of detection. However, colonoscopy may miss clinically important neoplastic polyps. The value of colonoscopy in reducing incidence of colorectal cancer is dependent on many factors including, the patient, provider, and facility level. A high quality examination includes adequate bowel preparation, optimal colonoscopy technique, meticulous inspection during withdrawal, identification of subtle flat lesions, and complete polypectomy. Considerable variation among institutions and endoscopists has been reported in the literature. In attempt to diminish this disparity, various approaches have been advocated to improve the quality of colonoscopy. The overall impact of these interventions is not yet well defined. Implementing optimal education and training and subsequently analyzing the impact of these endeavors in improvement of quality will be essential to augment the utility of colonoscopy for the prevention of colorectal cancer.     

Risk factors associated with missed colorectal flat adenoma: A multicenter retrospective tandem colonoscopy study

AIM: To determine the miss rate for colorectal flat adenomas during colonoscopy and the risk factors. METHODS: Flat adenomas are frequently missed during colonoscopy. However, the risk factors that influence their miss rates are unclear. This was a multicenter, retrospective study in which patients diagnosed with colorectal adenomas at a diagnostic colonoscopy and followed within 3 mo by a second therapeutic colonoscopy were pooled out from the established database. The “per-patient” and “per-adenoma” adenoma miss rates (AMR) for overall adenomas and flat adenomas, and patient-, adenoma-, and procedure-related risk factors potentially associated with the “per-adenoma” AMR for flat adenomas were determined. RESULTS: Chromoscopy and high-definition colonoscopy were not taken under consideration in the study. Among 2093 patients with colorectal adenomas, 691 (33.0%) were diagnosed with flat adenomas, 514 with concomitant protruding adenomas and 177 without. The “per-patient” AMR for flat adenomas was 43.3% (299/691); the rates were 54.3% and 11.3%, respectively, for those with protruding adenomas and those without (OR = 9.320, 95%CI: 5.672-15.314, χ² = 99.084, P < 0.001). The “per-adenoma” AMR for flat adenomas was 44.3% (406/916). In multivariate analysis, older age, presence of concomitant protruding adenomas, poor bowel preparation, smaller adenoma size, location at the right colon, insufficient experience of the colonoscopist, and withdrawal time < 6 min were associated with an increased “per-adenoma” AMR for flat adenomas. The AMR for flat adenomas was moderately correlated with that for overall adenomas (r = 0.516, P < 0.0001). The AMR for flat adenomas during colonoscopy was high. CONCLUSION: Patient’s age, concomitant protruding adenomas, bowel preparation, size and location of adenomas, proficiency of the colonoscopist, and withdrawal time are factors affecting the “per-adenoma” AMR for flat adenomas.     

Indications and techniques for lower intestinal endoscopy

The search for inflammatory and neoplastic lesions are the main indications for colonoscopy. A high rate of detection of polyps has become a quality criterion that depends on skilled handling of the colonoscope, on expertise and concentration during the examination, on excellent bowel preparation, and on a high standard of technical equipment. The diagnostic benefits outweigh the risk of bleeding, perforation and infection in almost all situations. Contraindications are signs of perforated intestine or imminent perforation due to deep ulcerations, necroses, or fulminant colitis. The patient's comorbidity must be considered to assess the physical stress of bowel preparation, colonoscopy and sedation. Informed consent is necessary and must be documented in all cases. It is advisable to explain planned therapeutic manoeuvres before the examination, since all non-invasive polyps must be removed completely. Total colonoscopy is possible in 95-99% of cases, but technical efforts are under way to solve the problem of looping and fixed colon angulations. Optimising optical imaging is another main focus of industrial development. The combination of narrow-band imaging, zoom magnification, and high-definition processor technology is currently the most promising tool for identifying small and flat lesions in the colon.     

Colonoscopic polypectomy in retroflexion

BACKGROUND: Little has been written about the value of retroflexion in the removal of large sessile colon polyps. OBJECTIVE: The objective of the study was to evaluate the utility of retroflexion for removal of large sessile colon polyps. DESIGN: This was a retrospective evaluation of consecutive cases. SETTING: This study was conducted at an academic-hospital-based tertiary-referral colonoscopy practice. PATIENTS: The study comprised consecutive patients with sessile polyps > or = 2 cm who were undergoing endoscopic resection. INTERVENTIONS: The intervention was endoscopic resection of 59 consecutive sessile colon polyps 2 cm or larger in size and located proximal to the rectum by using prototype colonoscopes with short bending sections. MAIN OUTCOME MEASURES: The main outcome measurement was successful endoscopic resection. RESULTS: Fourteen of the polyps were removed either entirely (n = 4) or partially (n = 10) in retroflexion. Patients with polyps that were removed in retroflexion were more likely to have been referred by another colonoscopist than those patients with polyps removed entirely in the forward view (p = 0.05). There were no perforations and no complications related to retroflexion. LIMITATIONS: The study is retrospective, and the practice is a tertiary referral colonoscopy practice. The colonoscopes used are not widely available at this time. CONCLUSIONS: Retroflexion is a useful adjunctive procedure for the removal of some colon polyps proximal to the rectum that are difficult to access endoscopically. The use of retroflexion can increase the fraction of proximal sessile colon polyps amenable to endoscopic resection.