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.     

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.     

A prospective comparative study of narrow-band imaging, chromoendoscopy, and conventional colonoscopy in the diagnosis of colorectal neoplasia

BACKGROUND: Discrimination between neoplastic and non-neoplastic lesions is crucial in colorectal cancer screening. Application of narrow-band imaging (NBI) in colonoscopy visualises mucosal vascular networks in neoplastic lesions and may improve diagnostic accuracy. AIM: To compare the diagnostic efficacy of NBI in differentiating neoplastic from non-neoplastic colorectal lesions with diagnostic efficacies of standard modalities, conventional colonoscopy, and chromoendoscopy. METHODS: In this prospective study, 180 colorectal lesions from 133 patients were observed with conventional colonoscopy, and under low-magnification and high-magnification NBI and chromoendoscopy. Lesions were resected for histopathological analysis. Endoscopic images were stored electronically and randomly allocated to two readers for evaluation. Sensitivity, specificity and diagnostic accuracy of each endoscopic modality were assessed by reference to histopathology. RESULTS: NBI and chromoendoscopy scored better under high magnification than under low magnification in comparison with conventional colonoscopy. The diagnostic accuracy of NBI with low or high magnification was significantly higher than that of conventional colonoscopy (low magnification: p = 0.0434 for reader 1 and p = 0.004 for reader 2; high magnification: p<0.001 for both readers) and was comparable to that of chromoendoscopy. CONCLUSION: Both low-magnification and high-magnification NBI were capable of distinguishing neoplastic from non-neoplastic colorectal lesions; the diagnostic accuracy of NBI was better than that of conventional colonoscopy and equivalent to that of chromoendoscopy. The role of NBI in screening colonoscopy needs further evaluation.     

Comparative study of conventional colonoscopy, chromoendoscopy, and narrow-band imaging systems in differential diagnosis of neoplastic and nonneoplastic colonic polyps

AIM: To identify the feasibility of the narrow-band imaging (NBI) method compared with that of conventional colonoscopy and chromoendoscopy for distinguishing neoplastic and nonneoplastic colonic polyps. METHOD: This study enrolled consecutive patients who underwent colonoscopy using a conventional colonoscope between January and February 2006 at Chang-Gung Memorial Hospital, Linkou Medical Center, Taiwan. These 78 patients had 110 colorectal polyps. During the procedure, conventional colonoscopy first detected lesions, and then the NBI system was used to examine the capillary networks. Thereafter indigo carmine (0.2%) was sprayed directly on the mucosa surface prior to evaluating the crypts using a conventional colonoscope. The pit patterns were characterized using the classification system proposed by Kudo. Finally, a polypectomy or biopsy was performed for histological diagnosis. RESULTS: Of the 110 colorectal polyps, 65 were adenomas, 40 were hyperplastic polyps, and five were adenocarcinomas. The NBI system and pit patterns for all lesions were analyzed. For differential diagnosis of neoplastic (adenoma and adenocarcinoma) and nonneoplastic (hyperplastic) polyps, the sensitivity of the conventional colonoscope for detecting neoplastic polyps was 82.9%, specificity was 80.0% and diagnostic accuracy was 81.8%, significantly lower than those achieved with the NBI system (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%) and chromoendoscopy (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%). Therefore, no significant difference existed between the NBI system and chromoendoscopy during differential diagnosis of neoplastic and nonneoplastic polyps. CONCLUSION: The NBI system identified morphological details that correlate well with polyp histology by chromoendoscopy.     

自发荧光内镜与标准白光内镜在大肠息肉筛查中作用的对照研究

目的比较自发荧光内镜成像技术（AFI）模式下和标准白光技术（WL）模式下内镜对大肠息肉检出率的差异。方法对2008年12月至2009年8月间纳入的562例按照计算机随机数字表分成2组。A组在WL模式下进镜至盲肠后，用WL模式退镜检查至直肠，接着再次用WL模式进镜至盲肠，然后改用AFI模式退镜检查至直肠；B组退镜检查与A组顺序相反。在首次发现息肉时即取活检，以示标记，并记录下息肉的部位、大小及形态，所有活检标本送组织学检查以明确病理类型。结果在A组中，WL模式下先发现息肉78枚，AFI模式下新发现额外息肉28枚；在B组中，AFI模式下先发现息肉106枚，WL模式下新发现额外息肉20枚。对数据进行统计显示，AFI模式下内镜对息肉的漏诊率为15．9％（20／126），显著低于WL模式下的26．4％（28／106）（P=0．041）。结论AFI内镜对于大肠息肉的筛查敏感性高，且操作简单易行，可推广应用。     

Narrow-band imaging colonoscopy--a pilot feasibility study for the detection of polyps and correlation of surface patterns with polyp histologic diagnosis

BACKGROUND: Colonoscopy is the preferred screening method for colorectal cancer. However, it has a substantial miss rate for colon polyps, and several techniques have been attempted to improve this limitation. Narrow-band imaging (NBI) is a novel technology that enhances the visualization of surface mucosal and vascular patterns. OBJECTIVE: The aim of this study was to determine the detection rate of additional polyps by NBI after removal of polyps visualized by standard white light colonoscopy (WLC) and to correlate the surface mucosal and vascular patterns with polyp histologic diagnosis. DESIGN: This was a prospective pilot feasibility study. SETTING: Kansas City Veterans Affairs Medical Center. PATIENTS: Subjects referred for screening colonoscopy were prospectively enrolled. METHODS: Subjects underwent colonoscopy after enrollment. After intubation of the cecum, colonic segments were sequentially examined, initially with WLC with removal of polyps followed by re-examination of the same segment with NBI. Additional polyps seen with NBI were photographed for their surface patterns and then removed. The total number of polyps visualized by WLC and NBI was calculated and the surface patterns were then correlated with polyp histologic features. RESULTS: Forty patients were enrolled in the study, all men, 32 white. The mean age was 62 years. A total of 72 polyps were detected by WLC (43 tubular adenoma, 28 hyperplastic polyps), whereas NBI detected an additional 51 polyps, of which 29 were tubular adenomas and 22 were hyperplastic. Five different surface/vascular patterns were observed: fine capillary network with absent mucosal pattern, circular pattern with dots, round/oval pattern, tubular pattern, and gyrus pattern. The sensitivity, specificity, and overall accuracy of the first two patterns for hyperplastic polyps were 86%, 96%, and 92%, respectively, and of the latter three patterns for tubular adenomas were 96%, 86%, and 92%, respectively. CONCLUSIONS: This pilot study demonstrates the feasibility of polyp detection and histologic correlation with NBI. These findings need to be confirmed in future randomized controlled trials.     

Predictive value of morphologic characteristics in rectosigmoid adenomatous polyps for the probability of synchronous polyps or cancer in the proximal colon.

BACKGROUND/AIMS: Sigmoidoscopy is performed more frequently than colonoscopy, especially for screening purposes and searching for colorectal neoplasm. The necessity of colonoscopy in patients with an adenoma ofor=11 mm) polyps. These groups were compared regarding the presence of proximal adenoma and advanced proximal neoplasia (>10 mm adenoma and/or villous histology and/or high grade dysplasia or cancer). Polyps found in the rectum and sigmoid colon were considered as distal polyps and polyps other than these were considered as proximal polyps. RESULTS: In this study, of 1124 consecutive patients who underwent colonoscopy between April 1997 and January 2002, 184 (16%) had 258 adenomatous polyps in the rectosigmoid area. The polyps were diminutive (or=11 mm) in 33 patients. Forty-one of the patients (39%) with diminutive polyps, 20 of the patients (43%) with small polyps and 19 of the patients (57%) with large polyps had neoplasm in the proximal bowel. In these patients, advanced proximal neoplasm was found in 8 (8%), in 6 (13%) and in 11 (33%), respectively. There was no difference regarding the presence of neoplasm in the proximal colon between these groups. The rate of advanced proximal neoplasm was found to be significantly higher in the group with large polyps in the rectosigmoid area than in the groups with small and diminutive polyps (p<0.05). In 104 patients (57%) with polyp(s) in rectum and sigmoid colon, no associated polyp or cancer was encountered in the proximal colon. CONCLUSION: Colonoscopy is indicated when adenomatous polyp, regardless of size, is found on rectosigmoidoscopy performed because of symptoms.     

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.     

内镜窄带成像与染色技术诊断大肠肿瘤的对比研究

目的通过窄带成像技术（NBI）和染色放大方法对大肠新生性病变进行观察，比较这两种技术对大肠肿瘤及非肿瘤性病变的鉴别诊断精度差异。方法2006年6月至9月间，共302例年龄在加至80岁之间的患者进行了NBI肠镜检查，其中98例入选。内镜插入至回盲部，退镜时分别采用常规模式、NBI模式观察，发现病变后，分别用NBI模式及染色放大方法进行血管分型及腺管开口分型，然后行病理检查进行评价比较。结果在98例患者发现新生性病变147个，其中常规内镜下发现的病变有90．5％（133／147），采用NBI发现病变有98．6％（145／147），差异有统计学意义（P〈0．01），漏诊的主要为平坦型病变。NBI观察对肿瘤性或非肿瘤的判断符合率为91．8％，染色内镜为82．3％（P〈0.01）。结论NBI技术观察黏膜表面变化，判断肿瘤或非肿瘤病变的符合率比普通内镜和染色内镜高，敏感性强；操作转换简单易行，尤其有利于平坦型病变的发现及诊断。     

Rectosigmoid findings are not associated with proximal colon cancer： Analysis of 6 196 consecutive cases undergoing total colonoscopy

AIM: To review the risk of proximal colon cancer in patients undergoing colonoscopy. METHODS: We estimated the risk of advanced proximal adenomas and cancers in 6 196 consecutive patients that underwent colonoscopy (mean age 60 years, 65% males, without prior history of colorectal examination). Neoplasms were classified as diminutive adenoma (5 mm or less), small adenoma (6-9 mm), advanced adenoma (10 mm or more, with villous component or high-grade dysplasia) and cancer (invasive adenocarcinoma). The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal colon (from cecum to descending colon). RESULTS: The trend of the prevalence of advanced proximal adenoma was to increase with severe rectosigmoid findings, while the prevalence of proximal colon cancer did not increase with severe rectosigmoid findings. Among the 157 patients with proximal colon cancer, 74% had no neoplasm in the rectosigmoid colon. Multivariate logistic-regression analysis revealed that age was the main predictor of proximal colon cancer and existence of rectosigmoid adenoma was not a predictor of proximal colon cancer. CONCLUSION: Sigmoidoscopy is inadequate for colorectal cancer screening, especially in older populations.     

Polyp detection rates using magnification with narrow band imaging and white light

AIM: To compare the yield of adenomas between narrow band imaging and white light when using high definition/magnification. METHODS: This prospective, non-randomized comparative study was performed at the endoscopy unit of veteran affairs medical center in Phoenix, Arizona. Consecutive patients undergoing first average risk colorectal cancer screening colonoscopy were selected. Two experienced gastroenterologists performed all the procedures that were blinded to each other's findings. Demographic details were recorded. Data are presented as mean ± SEM. Proportional data were compared using the χ2 test and means were compared using the Student's t test. Tandem colonoscopy was performed in a sequential and segmental fashion using one of 3 strategies: white light followed by narrow band imaging [Group A: white light(WL) → narrow band imaging(NBI)]; narrow band imaging followed by white light(Group B: NBI → WL) and, white light followed by white light(Group C: WL → WL). Detection rate of missed polyps and adenomas were evaluated in all three groups. RESULTS: Three hundred patients were studied(100 in each Group). Although the total time for the colonoscopy was similar in the 3 groups(23.8 ± 0.7, 22.2 ± 0.5 and 24.1 ± 0.7 min for Groups A, B and C, respectively), it reached statistical significance between Groups B and C(P 0.05). The cecal intubation time in Groups B and C was longer than for Group A(6.5 ± 0.4 min and 6.5 ± 0.4 min vs 4.9 ± 0.3 min; P 0.05). The withdrawal time for Groups A and C was longer than Group B(18.9 ± 0.7 min and 17.6 ± 0.6min vs 15.7 ± 0.4 min; P 0.05). Overall miss rate for polyps and adenomas detected in three groups during the second look was 18% and 17%, respectively(P = NS). Detection rate for polyps and adenomas after first look with white light was similar irrespective of the light used during the second look(WL → WL: 13.7% for polyps, 12.6% for adenomas; WL → NBI: 14.2% for polyps, 11.3% for adenomas). Miss rate of polyps and adenomas however was significantly higher when NBI was used first(29.3% and 30.3%, respectively; P 0.05). Most missed adenomas were ≤ 5 mm in size. There was only one advanced neoplasia(defined by size only) missed during the first look. CONCLUSION: Our data suggest that the tandem nature of the procedure rather than the optical techniques was associated with the detection of additional polyps' and adenomas.     

The use of indigocarmine spray increases the colonoscopic detection rate of adenomas

Purpose  It remains controversial whether chromocolonoscopy using indigocarmine increases the detection of colorectal polyps. We aimed to assess the impact of indigocarmine dye spray on the detection rate of adenomas and the feasibility of learning the technique in a Western practice. Methods  400 patients were prospectively allocated into 2 groups; A (n = 200): indigocarmine chromocolonoscopy was performed by a Japanese colonoscopist with expertise in chromoscopy; B (n = 200): initial 100 patients (B-1), a Western colonoscopist with no previous experience of chromoscopy performed conventional colonoscopy, but with at least 10 min observation during colonoscopy withdrawal. In the next 100 patients (B-2), he performed chromocolonoscopy. All polyps found were resected. Regression analysis was used to compare the numbers of polyps detected in groups A, B-1 and B-2, whilst controlling for gender, age, indication and history of colorectal cancer. Results  There were significant differences in the numbers of neoplastic polyps and flat adenomas between groups A and B-1 as well as between B-1 and B-2, but not between A and B-2. There was no significant difference in numbers of advanced lesions. Chromocolonoscopy (A and B-2) detected more neoplastic polyps of ≤5 mm. Conclusion  Chromocolonoscopy increases the detection of neoplastic polyps and flat adenomas, particularly diminutive polyps, but does not increase the detection of advanced lesions.     

内镜窄带成像技术在结肠肿瘤诊断中的价值

目的 将内镜窄带成像技术（NBI）、色素内镜检查结果与病理学检查结果进行对比,探讨NBI在结肠肿瘤诊断中的价值。方法78例患者96个结肠病变进行NBI放大观察并与染色放大内镜观察和最终病理结果进行比较。结果普通肠镜发现息肉的敏感性为78．7％,切换NBI后,能清楚显示息肉性病变的形态和边界,发现息肉的敏感性99％。放大NBI肠镜对于Ⅱ型,Ⅲ1型,Ⅳ型,ⅤN型息肉腺管开口的图像与色素内镜图像有较好的相似性,NBI对于腺管开口的识别能力明显优于普通结肠镜,但是次于色素内镜。NBI对息肉表面血管形态进行分类对判断结肠是否有肿瘤的能力,其敏感性为100％,特异性为87．8％,同样明显优于普通结肠镜,而次于色素内镜。结论NBI肠镜及色素内镜均能提高发现结肠息肉的特异性、敏感性。色素内镜能清晰显示病变表面结构和腺管开口,使内镜下对于肿瘤与非肿瘤的鉴别诊断接近病理诊断。NBI放大肠镜能清晰显示息肉表面的毛细血管形态,较好地区分肿瘤与非肿瘤。NBI内镜切换简单快捷,便于全结肠观察,利于发现早期结肠肿瘤。     

Randomized,back-to-back trial of a new generation NBI with a high-definition white light (HQ290) for detecting colorectal polyps

Abstract

Background: The benefits of narrow band imaging (NBI) for improving the detection rate of colorectal polyps remain unclear. New generation NBI using the 290 system (290-NBI) provides an at least two-fold brighter image than that of the previous version. We aimed to compare polyp miss rates between 290-NBI colonoscopy and high-definition white light endoscopy (HDWL).

Methods: In total, 117 patients were randomized to undergo either 290-NBI or HDWL from June 2015 to February 2017. In the HDWL group, we performed HDWL as an initial inspection, followed by a second inspection with NBI. In the 290-NBI group, NBI was performed as the initial inspection, followed by a second inspection with HDWL. We compared polyp and adenoma detection rates and polyp miss rates (PMR) between the two groups and analyzed the factors associated with the PMR.

Results: In total, 127 polyps were detected in the 117 patients. No differences in adenoma or polyp detection rates were observed between the two groups. The PMR for 290-NBI was 20.6% and that for HDWL was 33.9% (p?=?.068). However, the non-adenomatous PMR for 290-NBI was significantly lower than that of HDWL (11.5% vs. 52.2%, p?=?.002). Furthermore, the miss rates of polyps on the left side of the colon, flat-type polyps, and non-adenomatous polyps were significantly lower in the 290-NBI than HDWL.

Conclusions: New generation NBI may reduce PMR, especially of flat-type and non-adenomatous polyps and those on the left side of the colon. (UMIN000025505)     

Low-cost, Office-Based, Screening Colonoscopy

Objectives: Performing full colonoscopy at regular intervals and removing lesions at an early stage might significantly lower the incidence and mortality of colorectal cancer. Such a program must be inexpensive, safe, and time-efficient. Methods: Screening colonoscopy was performed on 639 patients. For a normal examination, the physician's time is limited to giving the medication for conscious sedation, performing the colonoscopy, and completing a written report form. The total charge for a normal screening colonoscopy is $150. Results: Adenomatous and/or hyperplastic polyps were detected in 218 patients (34.1%). One hundred sixty adenomatous and 134 hyperplastic polyps were removed. Forty-eight percent (48.1%) of the adenomatous and 21.6% of the hyperplastic polyps were ahove the sigmoid colon. Six adenocarcinomas were detected in five patients. One patient had a delayed hleeding episode requiring no transfusion or therapeutic intervention, and one patient had a "post-polypectomy syndrome" requiring no therapeutic intervention. The average physician time in the endoscopy room for normal examinations was 18 min. Conclusions: Screening colonoscopy can he safely performed in an office facility. Physician time with the patient should be limited to allow a low cost that compares favorably with screening costs for other malignancies. Long-term studies to assess the capability of screening colonoscopy to lower mortality from colorectal cancer should continue.     

Computed tomographic colonography compared with colonoscopy in patients at increased risk for colorectal cancer

BACKGROUND & AIMS: To date, computed tomographic (CT) colonography has been compared with an imperfect test, colonoscopy, and has been mainly assessed in patients with positive screening test results or symptoms. Therefore, the available data may not apply to screening of patients with a personal or family history of colorectal polyps or cancer (increased risk). We prospectively investigated the ability of CT colonography to identify individuals with large (>or=10 mm) colorectal polyps in consecutive patients at increased risk for colorectal cancer. METHODS: A total of 249 consecutive patients at increased risk for colorectal cancer underwent CT colonography before colonoscopy. Two reviewers interpreted CT colonography examinations independently. Sensitivity, specificity, and predictive values were determined after meticulous matching of CT colonography with colonoscopy. Unexplained large false-positive findings were verified with a second-look colonoscopy. RESULTS: In total, 31 patients (12%) had 48 large polyps at colonoscopy. This included 8 patients with 8 large polyps that were overlooked initially and detected at the second-look colonoscopy. In 6 of 8 patients, the missed polyp was the only large lesion. With CT colonography, 84% of patients (26/31) with large polyp(s) were identified, paired for a specificity of 92% (200-201/218). Positive and negative predictive values were 59%-60% (26/43-44) and 98% (200-201/205-206), respectively. CT colonography detected 75%-77% (36-37/48) of large polyps, with 9 of the missed lesions being flat. CONCLUSIONS: CT colonography and colonoscopy have a similar ability to identify individuals with large polyps in patients at increased risk for colorectal cancer. The large proportion of missed flat lesions warrants further study.     

Small polyps found during fiberoptic sigmoidoscopy in asymptomatic patients

STUDY OBJECTIVE: To determine the prevalence of small polyps in the rectosigmoid in an asymptomatic group and the likelihood of finding synchronous neoplastic polyps proximally at colonoscopy. DESIGN: Asymptomatic patients with polyps 9 mm or less found at screening fiberoptic sigmoidoscopy were referred for colonoscopy, at which time all polyps were removed. SETTING: Screening fiberoptic sigmoidoscopy unit. PATIENTS: Referral from Executive Health Wellness Clinic and large multispeciality clinic. RESULTS: From 3923 sigmoidoscopic examinations, 258 asymptomatic subjects (7%) were identified who had polyps 9 mm or smaller. One hundred and eighty-nine patients (73%) had colonoscopy. In 179 patients, the target lesion noted at sigmoidoscopy was identified at colonoscopy. Based on histology of the target lesion, patients were divided into three groups: Group 1 (72 patients) had only hyperplastic polyps; Group 2 (69 patients) had at least one neoplastic polyp; and Group 3 (31 patients) had polyps with normal histology. Seven patients were not classified. Neoplastic polyps were found proximally in 21 patients in Group 1 (29%; 95% CI, 19 to 39), 23 patients in Group 2 (33%; 95% CI, 22 to 44), and 4 patients in Group 3 (13%; 95% CI, 4 to 30). There was no difference in mean age between groups. The results were similar when only polyps 5 mm or smaller were analyzed. CONCLUSION: Because small polyps of any histologic type in the rectosigmoid indicate a high risk for having neoplastic polyps proximally, the guidelines of both the American College of Physicians and the American Society of Gastrointestinal Endoscopy may need to be revised. Colonoscopy seems justified in any patient in whom a small polyp is discovered at sigmoidoscopy.     

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.     

Colonoscopy in asymptomatic individuals with a family history of colorectal cancer

A prevalence screening program with colonoscopy was undertaken in four kindreds manifesting the cancer family syndrome. Forty-five percent of counseled patients underwent colonoscopy, providing 42 asymptomatic individuals. Seven patients (17%) were found to have adenomatous or villous polyps; two of these were malignant and one showed epithelial atypia. Three of the seven patients with polyps had multiple lesions. Only two patients had rectosigmoid polyps. From these limited data, colonoscopy is recommended as a useful screening procedure in individuals at high risk for colorectal cancer.     

Colon surveillance after colorectal cancer surgery

PURPOSE: This study was performed to determine costeffective colonoscopy guidelines for patients with prior colorectal adenocarcinoma. METHOD: A retrospective review was performed of patients who had been treated for colorectal adenocarcinoma and later underwent follow-up colonoscopy from 1984 to 1994. RESULTS: During this study period, 389 patients previously treated for colorectal adenocarcinoma underwent follow-up colonoscopy. All patients had perioperative colon evaluation for other neoplasms. Ages ranged from 26 to 89 (mean, 65.8) years, and 46.8 percent were female. Recurrent or metachronous cancer or a neoplastic polyp constituted a positive examination. Results of 389 first follow-up colonoscopies were compared with 259 second (66.6 percent), 165 third (42.4 percent), and 83 fourth (21.3 percent) follow-up examinations. Median interval between all colonoscopies was 13 months. Positive examination rates for the first two yearly examinations were 18.3 and 18.5 percent, respectively. Slightly lower, third-year and fourth-year positive examination rates were 16.4 and 14.5 percent, respectively. Fouryear examinations yielded the following: first year-1 carcinoid, 1 new adenocarcinoma, and 100 polyps; second year-1 anastomotic recurrence and 68 polyps; third year-55 polyps; and fourth year-1 recurrent cancer and 17 polyps. CONCLUSIONS: These data suggest that 1) annual follow-up colonoscopy for two years after colorectal cancer surgery is beneficial for detecting recurrent and metachronous neoplasms and 2) the interval between subsequent examinations may be increased depending on the result of the most recent examination.Read at the meeting of The American Society of Colon and Rectal Surgeons, Orlando, Florida, May 8 to 13, 1994.