The role of high-magnification-chromoscopic colonoscopy in hereditary nonpolyposis colorectal cancer screening: a prospective "back-to-back" endoscopic study

BACKGROUND: In hereditary nonpolyposis colorectal cancer flat and diminutive adenomas occur, particularly in the right colon. Such lesions may assume a high risk of malignant transformation. Interval cancers are known to occur in this group. Chromoscopic colonoscopy enhances detection in patients assuming a moderate to high lifetime risk of colorectal cancer. AIM: To prospectively assess the efficacy of high-magnification-chromoscopic colonoscopy for the detection of neoplastic lesions in patients undergoing hereditary nonpolyposis colorectal cancer screening. METHODS: Twenty-five asymptomatic patients fulfilling modified Amsterdam criteria underwent "back-to-back" colonoscopy. Conventional colonoscopy with targeted chromoscopy was performed initially followed by pan-colonic chromoscopic colonoscopy. Diagnostic extubation times and volumes of normal saline and indigo carmine (IC) were controlled. RESULTS: Using conventional colonoscopy and targeted chromoscopy 24 lesions were detected in 13 patients (20 exophytic/4 flat). Pan-colonic chromoscopy identified a further 52 lesions in 16 patients (17 exophytic/35 flat). Pan-chromoscopy identified significantly more adenomas than conventional colonoscopy (p= 0.001) and a significantly high number of flat adenomas (p= 0.004). CONCLUSIONS: Pan-colonic chromoscopic colonoscopy improves detection of significant neoplastic lesions in hereditary nonpolyposis colorectal cancer screening. Pan-chromoscopy may help better stratify colorectal cancer "risk" in this cohort and aid planning of surveillance colonoscopic follow-up.     

Detecting diminutive colorectal lesions at colonoscopy: a randomised controlled trial of pan-colonic versus targeted chromoscopy

BACKGROUND: Diminutive and flat colorectal lesions can be difficult to detect using conventional colonoscopic techniques. Previous data have suggested that pan-chromoscopy may improve detection rates. No randomised control trial has been performed examining detection rates of such lesions while controlling for extubation time and lavage effect. AIM: We conducted a randomised controlled trial of pan-colonic chromoscopic colonoscopy for the detection of diminutive and flat colorectal lesions while controlling for extubation time and lavage effect. METHODS: Consecutive patients attending for routine colonoscopy were randomised to either pan-chromoscopy using 0.5% indigo carmine (IC) or targeted chromoscopy (control group). A minimum diagnostic extubation time was set at eight minutes with controls undergoing a matched volume of saline wash. RESULTS: A total of 260 patients were randomised; 132 controls and 128 to pan-colonic chromoscopy. Extubation times did not differ significantly between the control (median 15 minutes (range 8-41)) and chromoscopy (median 17 minutes (range 8-39)) groups. The volume of IC used in the pan-chromoscopy group (median 68 ml (range 65-90)) and normal saline used in the control group (69 ml (range 60-93)) did not differ significantly. There was a statistically significant difference between the groups regarding the total number of adenomas detected (p<0.05) with significantly more diminutive (<4 mm) adenomas detected in the pan-chromoscopy group (p = 0.03). Pan-chromoscopy diagnosed more diminutive and flat lesions in the right colon compared with controls (p<0.05), with more patients with multiple adenomas (>3) detected using pan-chromoscopy (p<0.01). Hyperplastic lesions were more commonly detected in the pan-chromoscopy group compared with controls (p<0.001). More hyperplastic polyps were detected in the left colon (86% rectosigmoid) using chromoscopy compared with controls. CONCLUSION: Chromoscopy improves the total number of adenomas detected and enhances the detection of diminutive and flat lesions. Importantly, eight diminutive lesions had foci of high grade dysplasia. Chromoscopy may benefit patients, assuming a high risk of colorectal cancer, and help in risk stratification and planning follow up colonoscopy intervals.     

色素放大结肠镜诊断结直肠隆起性病变的临床应用

目的 探讨色素放大结直肠镜结合Kudo分型在诊断结直肠病变中的临床应用价值。方法 对125例病人行常规内镜诊断后，对结直肠新生儿进行染色并结合Kudo分型作出色素放大内镜诊断，取标本作病理检查，将仙和色素放大内镜诊断结果与病理诊断结果相比较，观察符合率。结果 在125例病灶中，普通内镜下诊断为炎性息肉，管状腺瘤，绒毛状腺瘤和结直肠癌的病理符合率分别为：95．6％，80．0％，90．0％和100％，总病理符合率为85．6％；色素放大内镜诊断的病理经分别为100．0％，93．8％，99％和100．0％，总病理经为95．2％。结论 色素放大结肠镜对判断结直肠病变的性质有较高的病理符合率，并能有效提高微小，表浅隆起型病灶的检出率，具有较高临床应用价值。     

Further validation of magnifying chromocolonoscopy for differentiating colorectal neoplastic polyps in a health screening center

BACKGROUND AND AIM: The accuracy of conventional colonoscopy to differentiate neoplastic and non-neoplastic polyps is limited, justifying a biopsy for histologic analysis. Magnifying chromocolonoscopy has emerged as the best tool available for differentiating adenomatous and hyperplastic polyps during colonoscopy; however, magnifying endoscopes are rarely used in endoscopy units. This study aimed to further validate the effectiveness of magnifying chromocolonoscopy in the diagnosis of neoplastic colorectal polyps in a screening center. METHOD: Five hundred average-risk subjects were randomly divided into two groups: a magnifying chromocolonoscopy group and a conventional chromocolonoscopy group, each of 250 subjects. Lesions were analyzed according to Kudo's classification of pit pattern (types I-V) and additionally subdivided into non-neoplastic (types I-II) and neoplastic (types III-V). Lesions judged as neoplastic were resected and those judged as non-neoplastic were left in situ. Only lesions < or =10 mm were included in the study. Resected lesions were analyzed with histopathological examination. RESULTS: The overall accuracy of magnifying chromocolonoscopy for differentiating neoplastic lesions (95%, 135 of 142), was significantly higher than that of conventional chromocolonoscopy (84%, 102 of 122; P < 0.01). The accuracy of magnifying chromocolonoscopy for differentiating neoplastic lesions < or =5 mm was 94% (135 of 142), whereas that of conventional chromocolonoscopy was only 78% (69 of 89; P < 0.001). Results were not affected by the macroscopic types. CONCLUSION: Magnifying chromocolonoscopy is superior to conventional chromocolonoscopy for the diagnosis of colorectal neoplastic lesions in the setting of a health testing center.     

Prospective Observation of Small Adenomas in Patients After Colorectal Cancer Surgery Through Magnification Chromocolonoscopy

Purpose This study was designed to confirm the safety of not removing small adenoma in patients who undergo colorectal cancer surgery. Methods Patients who underwent surveillance colonoscopy after surgery were enrolled. The study was approved by our institutional review board. Colonoscopy was performed with magnification chromocolonoscopy. Benign adenomas of 6 mm or less in size, diagnosed based on both nonmagnified and magnified observation, were left unresected with a maximum of three polyps per patient. The sites of the polyps were marked by tattooing. Interval colonoscopy was performed predominantly yearly or biennially. Increase in size by 2 mm or larger was defined as significant. In follow-up, polyps were removed if they grew larger than 6 mm, were suspicious for high-grade dysplasia, or the patients requested to have polyps removal. Results Five hundred polyps in 284 patients met the above criteria and were not resected, and 412 polyps were followed by repeat colonoscopy. The mean observation period was 3.6 ± 2.2 years and the mean number of repeat colonoscopy was 3.6 ± 1.6. At the final colonoscopy, 71 percent of 412 polyps showed no change in size, 15 percent increased, 3 percent decreased, and 11 percent could not be identified. Eighty-eight polyps were resected endoscopically, and histology showed neither cancer nor adenomas with high-grade dysplasia. Two hundred fifty-five polyps detected in the same patient cohort during index/repeat colonoscopy were removed, including four adenomas with high-grade dysplasia and two T1 cancers. Conclusions Leaving small polyps is safe even in patients who have undergone colorectal cancer surgery, provided that careful observation is guaranteed. Supported in part by Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan. Read at the meeting of The American Society of Colon and Rectal Surgeons, St. Louis, Missouri, June 2 to 6, 2007.     

High resolution colonoscopy with chromoscopy versus standard colonoscopy for the detection of colonic neoplasia: a randomized study.

BACKGROUND & AIMS: High-resolution colonoscopy with chromoscopy (HRC) is a technique designed to improve the detection of colonic neoplasias. We prospectively compared standard colonoscopy (SC) and HRC in a randomized multicenter trial. METHODS: Patients (n = 203; age, 58 +/- 10 years; sex ratio, 1) were recruited according to the following criteria: (1) a history of either familial or personal colonic neoplasia or (2) alarm symptoms after the age of 60 years. After randomization, an SC was performed in 100 patients (resolution, < or = 410,000 pixels) and a HRC in 103 patients (Fujinon EC485ZW, 850,000 pixels). In the HRC group, each colonic segment was examined before and after spraying with indigo carmine 0.4%. RESULTS: Two hundred seventy-six polyps were detected in 198 patients. One hundred sixty of them were hyperplastic polyps, 116 were adenomas, and 2 were carcinomas. The numbers of hyperplastic polyps and purely flat adenomas were significantly higher in the HRC group than in the SC group (1.1 +/- 1.6 vs 0.5 +/- 1.4 and 0.22 +/- 0.68 vs 0.07 +/- 0.29, respectively; P = .01 and P = .04), but there was no significant difference in the total number of adenomas per patient (primary end point) detected between the HRC and the SC groups (0.6 +/- 1.0 vs 0.5 +/- 0.9, respectively). CONCLUSIONS: Although HRC improves detection of purely flat adenomas and hyperplastic polyps, the overall detection of colonic adenomas in a population at increased risk of neoplasia is not significantly improved. These findings do not support the routine use of HRC in clinical practice.     

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.     

Colon Polyps Detected by Contrast Chromoscopy Using Indigo Carmine Capsule

Contrast chromoscopy of the colon using indigo carmine capsule was performed in 287 patients from July 1990 to March 1991. The distribution and histological features of the polyps detected and resected in these patients were investigated. The overall prevalence of polyps (neoplastic and nonneoplastic) was 85.7% and that of neoplastic polyps was 57.1 %. Moreover, the prevalence of neoplastic polyps in 121 asymptomatic patients was 50.4%. A total of 1179 polyps were resected. Of this total, 1049 polyps were diminutive (>5 mm), and 130 polyps were >5 mm. Histological examinations revealed 35.6% of the diminutive polyps and 83.7% of the large polyps (>5 mm) were neoplastic. Proximally, diminutive neoplastic polyps predominated, accounting for 78% of all of the diminutive polyps in the right colon. The situation was reversed in the distal colon, where diminutive non-neoplastic polyps comprised 91% of all of the diminutive polyps in the rectum. The number of large polyps was evenly distributed throughout the colon. The incidence of carcinoma was 0.5% of the diminutive polyps and 10.1 % of the large polyps. Approximately 70% of all of the neoplastic polyps were located proximal to the sigmoid colon. These findings suggest that there are many more polyps present throughout the colon than previously estimated. This suggests that total colonoscopy be performed more thoroughly than before, by using for instance chromoscopy. Furthermore, all of the polyps encountered during colonoscopy should be removed due to the high prevalence of neoplasia, especially in the proximal side of the colon.     

Chromoendoscopic colonoscopy for detecting preneoplastic lesions in hereditary nonpolyposis colorectal cancer syndrome.

BACKGROUND & AIMS: In hereditary nonpolyposis colorectal cancer (HNPCC) syndrome, flat and small adenomas are particularly prone to malignant transformation but might be missed by standard colonoscopy. We prospectively studied the diagnostic yield of high-resolution colonoscopy coupled with chromoendoscopy for preneoplastic and neoplastic colorectal lesions in patients with HNPCC syndrome. METHODS: Thirty-six consecutive asymptomatic patients (mean age, 42 years) belonging to HNPCC families and receiving genetic counseling were enrolled in this prospective study. Colonoscopy was performed in 2 steps. Conventional colonoscopy was performed first, followed by a second colonoscopy with chromoendoscopy with indigo carmine (.4%) dye sprayed onto the entire proximal colon. RESULTS: Conventional colonoscopy identified 25 lesions (mean size, 4 +/- 3 mm) in 13 patients. Seven lesions, detected in 5 patients, were adenomas, 3 of which were located in the proximal colon. Chromoendoscopy identified additional 45 lesions (mean size, 3 +/- 1 mm) in 20 patients; most of these lesions were flat and hyperplastic. Eleven additional adenomas were detected in the proximal colon of 8 patients, and 8 of these 11 lesions were flat. The use of chromoendoscopy significantly increased the detection rate of adenomas in the proximal colon, from 3 of 33 patients to 10 of 33 patients (P = .045). CONCLUSION: Relative to conventional colonoscopy, high-resolution colonoscopy with chromoendoscopy markedly improves the detection of adenomas in patients with HNPCC syndrome and might help to prevent colorectal carcinoma in these patients with a very high risk of colorectal cancer.     

Wide angle colonoscopy with a prototype instrument: impact on miss rates and efficiency as determined by back-to-back colonoscopies

OBJECTIVE: Polyps are missed during conventional colonoscopy, even with meticulous technique. The aim of this study was to investigate whether a prototype wide angle colonoscope is associated with a reduced miss rate for polyps. METHODS: Two studies were performed. In study 1, a total of 50 patients underwent back-to-back, same-day colonoscopy by a single examiner with the prototype wide angle colonoscope and with a standard colonoscope, with the order of scopes randomized. In study 1, an attempt was made to keep examination time with the two colonoscopes equal. In study 2, a total of 20 patients were examined, 10 by the same colonoscopist who performed study 1 and 10 by a second colonoscopist. In study 2, examiners tried to perform the examinations as quickly as accuracy would allow. RESULTS: In study 1, the miss rate for all polyps was lower with the wide angle colonoscope (20% vs 31%; p = 0.046), although the mean examination time with the wide angle instrument was shorter (6.75 min vs 7.64 min; p = 0.0005). There was no significant difference in detection of adenomas. Polyps, including adenomas, were missed in the peripheral endoscopic field more frequently with the standard colonoscope. In study 2, wide angle colonoscopy was associated with reductions in examination time of 25% and 30% for the two examiners, respectively. Miss rates were the same for one colonoscopist but were higher for the other colonoscopist when the wide angle instrument was used. CONCLUSION: A prototype wide angle colonoscope did not eliminate polyp miss rates. Wide angle colonoscopy has the potential to reduce examination time and improve visualization of the periphery of the endoscopic field of view, but improvements in resolution are needed.     

High resolution chromoendoscopy in the differential diagnosis of neoplastic and non-neoplastic polyps

BACKGROUND: Magnifying colonoscopy brought the possibility of precise histologic diagnosis of colorectal lesions through their surface appearance. Despite the high accuracy of magnifying colonoscopy it is a specialized and expensive equipment not available in most medical centers. Due to these reasons the use of conventional colonoscopy with chromoscopy has been raised because this produce can reproduce most of the information previously obtained by magnifying colonoscopy. AIM: To determine the role of high resolution colonoscopy and indigo carmine chromoscopy for differential diagnosis between neoplastic and non-neoplastic colorectal lesions through measurements of accuracy, sensitivity, specificity, positive and negative predictive values. PATIENTS / METHODS: It was performed a prospective study. Seventy-four colorectal polyps were evaluated in 54 patients. A high resolution Olympus Exera CFQ 160L colonoscope was used. After the identification of the lesions, they were dyed with indigo carmine 0,2% and classified according to Kudo's classification by a single observer. After resection, the polyps were submitted to histopathological examination. RESULTS: The endoscopic findings were compared to histopathologic results. The accuracy of the method was 79,7%, sensibility of 88,8%, specificity of 55%, positive predictive value of 84,2% and a negative predictive value of 64,7%. CONCLUSION: We can conclude that we must be careful to apply high resolution colonoscopy and chromoscopy because adenomatous lesions can be misdiagnosed as non-neoplastic.     

NARROW BAND IMAGING IN THE DETECTION OF COLORECTAL POLYP: KOREAN EXPERIENCE

Background: Although white light (WL) colonoscopy is a gold standard to detect colorectal polyps, substantial polyps are missed. Narrow band imaging (NBI) is a new technology that enables a more detailed visualization of the mucosal surface. The aim of the present study was to determine whether NBI can improve the detection of colorectal polyps. Methods: We prospectively enrolled 188 (M : F = 99:89, 21–80 years) subjects undergoing colonoscopy as a screening procedure in nine referral centers. After a careful WL examination of the whole colorectum, rectosigmoid colon (0–30 cm from the anal verge) was reobserved by NBI. Size, macroscopic morphology, and the histology of all the polyps detected during WL and NBI examination were analyzed. Results: WL examination detected 162 polyps in 188 subjects, of which 106 lesions were neoplastic, while NBI of rectosigmoid colon detected an additional 61 polyps of which eight lesions were neoplastic. Only 10 (6.2%) of 162 polyps discovered during WL examination were flat polyps compared to 10 (16.4%) of 61 newly detected polyps during NBI being flat type (P = 0.002). The mean polyp size detected by NBI was smaller than that found by WL colonoscopy (2.8 ± 1.0 mm vs 6.5 ± 4.5 mm, P < 0.001). Conclusion: Many additional colorectal polyps, especially flat type, could be detected by NBI examination for normal‐looking rectosigmoid mucosa. The role of NBI in colorectal neoplasm screening needs to be further investigated in future studies.     

Detection of colorectal adenomas by routine chromoendoscopy with indigocarmine

OBJECTIVES: Nonpolypoid adenomas, which can be important precursors of colorectal cancers, are difficult to find during routine colonoscopy. The aim of this study was to evaluate the usefulness of routine chromoendoscopy in Korea, where the incidence of colorectal cancer is low compared with western countries. METHODS: Colonoscopy with chromoendoscopy was performed in 74 consecutive patients (48 men, 26 women; mean age 53.0 yr). After a careful examination of the whole colon, a defined segment of the sigmoid colon and rectum (0-30 cm from the anal verge) was stained with 20 ml of 0.2% indigocarmine solution with a spraying catheter. Nonpolypoid lesions were classified as flat or depressed types. Biopsies were taken from all lesions detected before or after staining with indigocarmine. RESULTS: Indications for colonoscopy included routine check-up (21 patients), diarrhea or loose stool (14 patients), abdominal pain (12 patients), constipation (7 patients), bleeding (6 patients), and others (14 patients). Before staining, 58 lesions were found in 30 patients (43.2%). Histology showed tubular adenoma in 41 lesions, hyperplastic or inflammatory changes in 14 lesions, adenocarcinoma in 2 lesions, and villous adenoma in 1 lesion. After indigocarmine staining for normal-looking distal 30 cm colorectal mucosa, 176 lesions were found in 46 patients (62.2%). Histologically, 158 lesions were hyperplastic or inflammatory in nature, and 17 lesions (from 11 patients) were tubular adenomas. There was one serrated adenoma. Eighteen adenomas seen only after spraying indigocarmine were 2.6 +/- 0.6 mm in diameter, and all of them were classified as flat adenomas. There was no depressed-type adenoma. No adenoma with high grade dysplasia, villous histology, or cancer was found after staining. Presence of macroscopic adenomatous lesions or carcinoma before staining could not predict the existence of adenoma after staining. CONCLUSIONS: In a large proportion of patients, flat or depressed adenomas could be found after spraying indigocarmine for normal-looking colorectal mucosa in Korea. The clinical significance of these diminutive adenomas that can be found only after spraying contrast agent needs to be further investigated.     

Physician Reminders to Promote Surveillance Colonoscopy for Colorectal Adenomas

Background  Most colorectal cancers develop from adenomatous polyps. National guidelines recommend surveillance colonoscopy within 5 years after such polyps are removed. Objective  To determine whether surveillance colonoscopy can be increased among overdue patients by reminders to their primary physicians. Design  Randomized, controlled trial of patient-specific reminders mailed to 141 physicians in 2 Massachusetts primary care networks during April, 2006. Patients  Seven hundred seventeen patients who had colorectal adenomas removed during 1995 through 2000 and no follow-up colonoscopy identified via automated review of electronic records through March, 2006. Measurements and Main Results  The use of colonoscopy and detection of new adenomas or cancer were assessed at 6 months by a blinded medical record review in all patients. Among 358 patients whose physicians received reminders, 33 (9.2%) patients underwent colonoscopy within 6 months, compared with 16 (4.5%) of 359 patients whose physicians did not receive reminders (P = 0.009). In prespecified subgroups, this effect did not differ statistically between 2 primary care networks, elderly and nonelderly patients, or women and men (all P > 0.60 by Breslow–Day test). New adenomas or cancer were detected in 14 (3.9%) intervention patients and 6 (1.7%) control patients (P = 0.06), representing 42.4% and 37.5% of patients who underwent colonoscopy in each group, respectively. Despite using advanced electronic health records to identify eligible patients, 22.5% of enrolled patients had a prior follow-up colonoscopy ascertained only by visual record review, and physicians reported 27.9% of intervention patients were no longer active in their practice. Conclusions  Among patients with prior colorectal adenomas, physician reminders increased the use of surveillance colonoscopy, but better systems are needed to identify eligible patients (ClinicalTrials.gov ID number NCT00397969). The study was presented at the Annual Meeting of the Society of General Internal Medicine in Toronto, Ontario on April 26, 2007.     

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.     

The mean number of adenomas per procedure should become the gold standard to measure the neoplasia yield of colonoscopy: A population-based cohort study

BackgroundMeasuring adenoma detection is a priority in the quality improvement process for colonoscopy. Our aim was (1) to determine the most appropriate quality indicators to assess the neoplasia yield of colonoscopy and (2) to establish benchmark rates for the French colorectal cancer screening programme.MethodsRetrospective study of all colonoscopies performed in average-risk asymptomatic people aged 50–74 years after a positive guaiac faecal occult blood test in eight administrative areas of the French population-based programme.ResultsWe analysed 42,817 colonoscopies performed by 316 gastroenterologists. Endoscopists who had an adenoma detection rate around the benchmark of 35% had a mean number of adenomas per colonoscopy varying between 0.36 and 0.98. 13.9% of endoscopists had a mean number of adenomas above the benchmark of 0.6 and an adenoma detection rate below the benchmark of 35%, or inversely. Correlation was excellent between mean numbers of adenomas and polyps per colonoscopy (Pearson coefficient r = 0.90, p < 0.0001), better than correlation between mean number of adenomas and adenoma detection rate (r = 0.84, p = 0.01).ConclusionThe mean number of adenomas per procedure should become the gold standard to measure the neoplasia yield of colonoscopy. Benchmark could be established at 0.6 in the French programme.     

Magnifying colonoscopy in differentiating neoplastic from nonneoplastic colorectal lesions

OBJECTIVE: Because the medical management of persons with adenomatous colorectal polyps differs from that of those with hyperplastic polyps, accuracy of diagnosis is essential. This study reports our experience using a magnifying colonoscope combined with indigocarmine dye to diagnose colorectal polyps, emphasizing its ability to differentiate neoplastic from nonneoplastic lesions. METHODS: The materials consisted of 175 polyps. A 0.2% indigocarmine solution was sprayed, and the colonoscope zoom apparatus performed a magnified observation after an ordinary colonoscopy identified the lesions. The pit patterns were classified into six categories: I, II, III(L), IIIs, IV, and V according to Kudo's modified classification. RESULTS: The percentages of neoplastic changes in the lesions with pit pattern I, II, III(L), IIIs, IV, and V were 0, 12.2, 69.7, 80, 84.4, and 100%, respectively. The diagnostic sensitivity of neoplastic lesions was 93.8% and specificity was 64.6% when types I and II represented the pit pattern of nonneoplastic lesions and types III(L), IIIs, IV, and V represented neoplastic lesions. The overall diagnostic accuracy in differentiating neoplastic from nonneoplastic lesions was 80.1%. The diagnostic accuracy is not influenced by the size and shape of the lesions. The six neoplastic lesions that were misjudged to be nonneoplastic were histologically adenoma with only mild atypia. CONCLUSIONS: The pit pattern analysis of colorectal lesions by magnifying colonoscopy is a useful and objective tool for differentiating neoplastic from nonneoplastic lesions of the large bowel. In its current state of development, however, this technique is not a substitute for histology.     

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.     

Two-Year Incidence of Colon Adenomas Developing after Tandem Colonoscopy

Objective: We attempted to determine an accurate frequency of new polyp growth in a cohort of veteran male patients who were initially cleared of polyps by tandem colonoscopy. Methods: Followup colonoscopy was performed 2 yr after tandem colonoscopy. A polyp was categorized as "new" if it was not located in a segment of the colon or rectum that had harbored a neoplastic polyp of the same histology at tandem colonoscopy, in contradistinction to lesions designated as "same-segment" polyps. Results: Fifty-eight of 90 patients who had tandem colonoscopy as a part of a previous study were available for follow-up colonoscopy for 2 yr. Ninety-one percent had a history of benign neoplastic polyps or cancer. Neoplastic polyps were documented in 52% (95% CI, 45–74%) of patients at followup, and 38% (95% CI, 26–52%) were found to have a total of 31 "new" lesions. All new lesions were tubular adenomas. The largest number of new polyps in an individual patient was four, and the largest new lesion was 20 mm in size with a flat, linear configuration. Most (25/31) new polyps were <5 mm, and the number of neoplastic polyps per patient at follow-up was less than at tandem colonoscopy. Conclusions: Approximately one-half of older, male patients with a history of neoplastic polyps will demonstrate neoplastic polyps at 2 yr. In at least one-third of patients, these appear to be new lesions. In some patients, de novo neoplastic polyps can grow to ≥1 cm within 2 yr.     

Reduction of miss rates of colonic adenomas by zoom chromoendoscopy

Background and aims The aim of this study was to determine the detection rate of polyps using zoom chromoendoscopy (ZE) compared with standard video colonoscopy.Patients and methods End-to-end colonoscopies were performed in 50 patients by two different endoscopists blinded for each other’s results. Lesions detected during initial standard colonoscopy (C1) were biopsied or removed by snare resection. The second colonoscopy (C2) was done with a zoom colonoscope spraying the whole colon with indigocarmine (0.4%). In addition, detected mucosal lesions were documented prior to ZE and then classified according to the pit pattern classification before biopsy or removal. The retrieval time for each procedure was determined. Results: The average retrieval time for C1 was 13±9 min (9–24) and 28±11 min (16–38, p<0.05) for ZE. During C1, 56 lesions were detected in 26 of 50 patients (34 hyperplastic and 22 adenomatous). During C2, 19 additional polyps were documented prior to ZE (15% tandem miss rate), and 20 further lesions were detected with ZE (21% additional polyp detection rate compared to C1 and C2 without ZE). Of the 39 additional lesions removed during C2 after ZE, 29 were hyperplastic and 10 were adenomatous. Most adenomas detected during the second investigation were found in patients in whom adenomatous polyps had already been removed during the initial colonoscopy (9 of 26 patients vs 1 of 24 patients, p<0.02). No carcinoma was detected. The pit pattern classification allowed a correct differentiation between hyperplastic and adenomatous polyps (accuracy 93%, sensitivity 90%, specificity 97%).Conclusion Using zoom chromoendoscopy, the rate of detecting colonic polyps can be increased at the cost of a longer retrieval time.