A comparison of colonoscopy and roentgenography for detecting polypoid lesions of the colon

This study compares the effectiveness of the roentgen and colonoscopic examination of the colon for detecting polypoid lesions. We evaluated the findings in 64 patients with suspected or known polypoid lesions who received the same colon cleansing regimen for both examinations, and were studied by examiners of similar expertise. As in other studies, the endoscopist had the advantage of knowing the roentgen findings, and the colonoscopic findings were often taken to indicate whether or not a lesion was present. In about half the patients, however, a second roentgen examination, repeat colonoscopy, or surgical specimen provided additional information for scoring. For example, a filling defect of the same size and location on two roentgen examinations, but not demonstrated at colonoscopy was scored as a false negative colonoscopic finding.The study results indicate that 54% of small polyps 0.9 cm in size were missed on roentgen examination, whereas no proven misses for lesions of this size were shown for colonoscopy. This absence of colonoscopic false-negative findings for small polyps, however, may be partially explained by a relative insensitivity of the roentgen method. For larger lesions 1.0 cm in size the miss-rate for the two examinations was similar: 15% for roentgen examination and 12% for colonoscopy.We conclude: (1) Colonoscopy is a more sensitive method than roentgen examination for detecting small polyps of the colon, and (2) Performance of the two examinations may be comparable for demonstrating lesions 1.0 cm or larger in size.     

Fiberoptic colonoscopic examination in surgical patients with colorectal cancer

A diagnostic and surveillance program using colonscopy in patients with colorectal cancer was established at North Carolina Memorial Hospital. The records of all patients who had preoperative or postoperative colonoscopic examination between 1976 and 1979 were reviewed. Fifty-five patients had colonscopic examination preoperatively. No additional disease was found in 39. In 15 patients, unsuspected additional disease was detected, and one patient had a suspected polyp ruled out by colonoscopic examination. One of these patients was found to have a synchronous primary cancer, not demonstrated by barium enema. Surgical treatment was modified in nine (16%) of these 55 patients by the preoperative colonoscopic findings. Sixty patients had colonoscopy six months to six years postoperatively. No additional disease was found in 47. Adenomatous polyps were found in eight. Two patients had recurrent cancer proved by colonoscopy, and three had a second primary cancer detected only by colonoscopy. Treatment was directly influenced by colonoscopy in eight (13.3%) of these 60 patients. These studies had a favorable cost/benefit ratio in patients with colorectal cancer and support a program of preoperative colonoscopy in patients with colorectal cancer and reexamination within two to three years after operation.     

Diagnostic yield of advanced colorectal neoplasia at colonoscopy, according to indications: an investigation from the Korean Association for the Study of Intestinal Diseases (KASID)

BACKGROUND AND STUDY AIMS: The factors that more accurately predict the detection of colorectal cancers and adenomas at colonoscopy are different. We conducted a prospective multicenter study to evaluate which indications were most closely associated with advanced colorectal neoplasm (CRN), including colorectal cancer, in a group of patients undergoing colonoscopy. PATIENTS AND METHODS: The 17 468 patients were enrolled in this study between July 2003 and March 2004, from 11 tertiary medical centers in Korea. They were recruited according to 11 itemized colonoscopic indications. The term "advanced adenoma" refers here to tubular adenomas of diameter of 11 mm or more, or to tubulovillous, villous, or severely dysplastic adenomas, irrespective of their size. Cancer was defined as the invasion of malignant cells beyond the muscularis mucosa. Advanced CRN was defined as advanced adenoma or invasive cancer. RESULTS: Advanced CRN was found in 1227/17 307 patients (1176 advanced adenomas plus 51 carcinomas, 7.1 %). According to univariate and multivariate analysis, the factors associated with advanced CRN included age >60 years (odds ratio (OR) 2.1, 95 % confidence interval (CI) 1.8 - 2.4, P < 0.0001), male gender (OR 2.1, 95 %CI 1.7 - 2.7, P < 0.0001), referral for colonoscopy from primary care physician (OR 3.1, 95 %CI 2.5 - 3.7, P < 0.0001), and several other indications (OR 1.8, 95 %CI 1.5 - 2.3, P < 0.001). The yield of colonoscopy for advanced CRN was lower (2.2 %) than expected in patients with iron-deficiency anemia (OR 0.5, 95 %CI 0.2 - 0.9, P = 0.03). CONCLUSIONS: Age, gender, and referral for colonoscopy from primary care physician constituted important independent predictors of advanced CRN in patients undergoing colonoscopy.     

Reasons for failure to diagnose colorectal carcinoma at colonoscopy

BACKGROUND AND STUDY AIMS: Colonoscopy can produce false-negative results, and the reasons for this remain obscure. The aim of this study was to examine why cancers are missed at colonoscopy. PATIENTS AND METHODS: All colonoscopies carried out at Christchurch Hospital, New Zealand, over a 43-month period (1 October 1997 - 30 April 2001) were retrospectively analyzed (the data having been prospectively collected). All cases of colorectal carcinoma during the period 1 October 1997 - 30 July 2001 (3 months longer, to capture delayed diagnoses) were also identified. The two databases were then compared, and all cases in which a colonoscopy had been performed more than 6 weeks before a colorectal carcinoma specimen being received by the pathology department were identified and analyzed. RESULTS: A total of 5055 colonoscopies were undertaken in 4598 patients. Over this period, 630 colorectal carcinomas were identified in the pathology database; 286 of the patients affected were in the colonoscopy and pathology database. Sixty-six patients had had a colonoscopy performed more than 6 weeks before the diagnosis of colorectal carcinoma. Carcinoma was identified in 48 of these 66 patients, and management was being provided. Seventeen cancers (5.9 %) were missed at colonoscopy, and the patients had had an incomplete colonoscopy in nine of these cases. In seven of the 17, an alternative benign cause was recorded. In four patients, a lesion was seen and thought to be benign, although subsequently proven not to be. In another four cases, the cancer was not diagnosed despite adequate bowel preparation and what was thought by the colonoscopist to be an adequate colonoscopy. CONCLUSIONS: Colonoscopy missed 17 of 286 cancers (5.9 %). The reasons why cancers were missed relate to incomplete colonoscopy, poor bowel preparation, misinterpretation of what was seen, failure to carry out adequate biopsy (and follow-up) of lesions seen, and systems failures related to follow-up investigations in patients who had an incomplete colonoscopy. The fact that colonoscopy and barium enema investigations may fail to diagnose cancers has important medicolegal implications. The recognition that colonoscopy may miss a cancer should encourage doctors to reinvestigate patients when there is a lack of correlation between the clinical and investigative findings.     

Ultrasonographic diagnosis of advanced colorectal cancer

We investigated the efficacy of transabdominal ultrasonography for the diagnosis of advanced colorectal cancer. Colonic examination by colonoscopy, barium study, or surgery was carried out in our institution on 1579 patients during the past 5 years. This study focused on 1564 of these patients, 15 who has been diagnosed with colorectal cancer before ultrasound examination having been excluded. The results included 51 ultrasound-positive cases, 9 ultrasound-false-positive cases, 1476 ultrasound-negative cases, and 28 ultrasound-false-negative cases. Sensitivity was 64.6 percent and specificity was 99.6 percent. Of the 28 ultrasound-false-negative cases, the lesion was detected in the ascending colon in 2, in the transverse colon in 6, in the descending colon in 1, in the sigmoid colon in 3, and in the rectum in 16. Obstruction and dilatation suggested colorectal cancer in 3 cases, which were thus classified as ultrasound-negative when no tumors were detected. Sensitivity was investigated by site. Sensitivity was lowest at 30.4 percent in rectal cancer, but was 78.6 percent in colon cancer, exclusive of rectal cancer. Laboratory findings and clinical symptoms which were suggestive of colorectal cancer were used as information before ultrasound examination was performed. Sensitivity of examinations carried out on examinees on whom prior information was available and on those on whom there was no information did not differ significantly. Furthermore, ultrasound was thought to detect approximately 65 percent of advanced colorectal cancers when it was used aggressively to investigate the large intestine. Ultrasound was thus considered effective for detecting advanced colorectal cancer.     

Colonoscopy surveillance after polypectomy and colorectal cancer resection

This article describes a joint update of guidelines by the American Cancer Society and the U.S. Multi-Society Task Force on Colorectal Cancer delineating evidence-based surveillance recommendations for patients after polypectomy and colorectal cancer resection. Although there are some qualifying conditions, the following general guidelines apply: after colonoscopic polypectomy, patients with hyperplastic polyps should be considered to have normal colonoscopies, and subsequent colonoscopy is recommended at 10 years. Patients with one or two small (less than 1 cm) tubular adenomas, including those with only low-grade dysplasia, should have their next colonoscopy in five to 10 years. Patients with three to 10 adenomas, any adenoma 1 cm or larger, or any adenoma with villous features or high-grade dysplasia should have their next colonoscopy in three years. Following curative resection of colorectal cancer, patients should undergo a colonoscopy at one year, with subsequent follow-up intervals determined by the results of this examination. Adoption of these guidelines will have a dramatic impact on the quality of care provided to patients after a colorectal cancer diagnosis, will assist in shifting available resources from intensive surveillance to screening, and will ultimately decrease suffering and death related to colorectal cancer.     

Colonoscopic manifestations of primary colorectal lymphoma

BACKGROUND AND STUDY AIMS: Little is known about the colonoscopic manifestation of colorectal lymphoma. This article describes the use of colonoscopy for diagnosis of primary colorectal lymphoma. PATIENTS AND METHODS: We analyzed colonoscopic findings in 13 retrospectively collected cases of primary colorectal lymphoma diagnosed between 1990 and 1999 at our hospital. RESULTS: The primary colorectal tymphomas were distinguished into three colonoscopic types: a) the mucosal type, which included six lymphomas (46%), which were classified into two subtypes, erosive (two lymphomas) and ulcerative (four tymphomas); b) the polypoid type, which included three tymphomas (23%); and c) the massive type, which included four (31%). The proportion of patients with T-cell lineage lymphoma (5 of 12, 42%) was higher than in previous studies. Three cases were diagnosed as enteropathy-associated T-cell (EAT)-like lymphoma: one presenting with multicentric ulcerations, one as a massive type and another as a polypoid type. Of those with B-cell lineage lymphoma (7 of 12, 58%), three presented as massive type, two as polypoid type and two as erosive subtype. CONCLUSIONS: Based on the analysis of colonoscopic records, we have proposed three main types of primary colorectal lymphoma. An unusually high proportion of T-cell lineage lymphomas was noted, but as the number of cases was low, further study is still needed for confirmation.     

Colon polyps and cancer

A large number of studies published last year in peer-reviewed medical journals help to better define the advantages and limitations of the different options for colorectal cancer screening. Direct colonoscopy screening appears to have the greatest potential to markedly reduce both the incidence and mortality of colorectal cancer, but many obstacles limiting its widespread use in the general at-risk population still exist, and many questions remain incompletely answered. Recent studies stress the fact that finding and resecting advanced adenomatous polyps, and thereby preventing cancer, is becoming a primary objective of screening programs. Several papers also show the potential of emerging new methods of screening for specific markers in stool and for imaging the colon with computed-tomographic colonography (virtual colonoscopy). Other important publications highlighted in this review deal with the diagnosis of colorectal neoplasia, familial colorectal cancer, colorectal polyps and the adenoma-carcinoma sequence, and new and novel methods of improving the efficiency and safety of colonoscopic polypectomy.     

56例大肠癌术后结肠镜随访检查结果分析

目的：观察大肠癌患根治性切除术后局部复发情况。方法：患术后每隔3个月，半年，1年及2年各作一次肠镜检查及病理组织活检，以观察肿瘤复发情况。结果：大肠癌术后1－2年为好发期，其局部复发与大肠癌原发部位，Dukes分明，组织学类型及分化程度有关，结论：大肠癌患术后都应该在无症状时进行定期的内镜随访检查，以期早期发现，早期治疗术后复发的肿瘤。     

Colonoscopy and multidetector-array computed-tomographic colonography: detection rates and feasibility

BACKGROUND AND STUDY AIMS: Computed-tomographic (CT) colonography has been introduced as a minimally invasive colon examination for the detection of colorectal neoplasms. The aim of this study was to compare the performance characteristics of multidetector-array CT colonography (MDCTC) and conventional colonoscopy in a prospective, blinded design. PATIENTS AND METHODS: Sixty-six symptomatic patients, 75 patients undergoing polyp and cancer surveillance, and seven patients undergoing preoperative colonoscopy due to colorectal cancer (CRC) were examined with MDCTC and subsequent colonoscopy. The gold standard was colonoscopy. If MDCTC was positive and the first-pass colonoscopy was negative, a second-pass colonoscopy served as the gold standard. RESULTS: Complete colonoscopy was achieved in 91% of the patients, while technically satisfying MDCTC was obtained in 76% of the patients (P < 0.01), insufficient air distension in the sigmoid colon being the main problem. MDCTC and colonoscopy both detected all 11 carcinomas. Overall detection rates for polypoid lesions 6 mm or larger in size were 81% (95% CI, 70% to 90%) for MDCTC and 87% (95% CI, 77% to 94%) for colonoscopy (P = 0.52), with a significant difference with regard to the detection of polyps 6-9 mm in size in favor of colonoscopy (P = 0.008). The specificity of MDCTC at a 6-mm level was 97% (95% CI, 92% to 99%). CONCLUSIONS: MDCTC and colonoscopy show equal overall sensitivity for the detection of polypoid lesions 6 mm or larger in size, but more patients are inadequately examined when MDCTC is used.     

Colon polyps and cancer.

The superiority of colonoscopy to double-contrast barium enema in detecting neoplasia was finally demonstrated in 2000, but colonoscopic surveillance programs are still based on short-term observations and are mostly inadequate, despite the prospective design of the trials. The evaluation of the diagnostic accuracy of virtual colonoscopy is in progress, but its appropriate place in clinical gastroenterology has not yet been defined. There is now solid evidence that screening with fecal occult blood testing (FOBT) not only reduces the mortality from colorectal cancer, but also that the incidence is substantially reduced after removal of the precursor lesions. Feasibility studies for population screening are ongoing. A once-only sigmoidoscopy will probably not be an optimal method of screening, but may be added to a program with FOBT. Molecular stool screening is attractive, but still experimental. Colonoscopy is not attractive as an initial screening instrument, despite its high diagnostic accuracy, and should only be used for screening high-risk individuals. Genetic methods are playing an increasing role in defining prognostic markers for intestinal neoplasia, and it is recommended that information services should be established for the public. Chemopreventive studies have revealed that dietary fiber supplementation may not reduce the risk of adenomas; the opposite seems to be true for aspirin and non-aspirin NSAIDs, which are active in the early phase of carcinogenesis. New techniques for optimizing diagnostic and therapeutic colonoscopy have been introduced.     

Colon polyps and cancer

During 1999-2000, a number of important issues related to endoscopy and colorectal polyps and cancer were investigated. Several papers consider whether flat adenomas with high malignant potential are as common in the West as in Japan. Clinical series indicate that signs of rectal bleeding are more predictive of colorectal cancer than gastrointestinal symptoms. Colonoscopy is more accurate than double-contrast barium enema for detecting polyps, and virtual colonoscopy is a promising new diagnostic and screening technique. Primary prevention dietary studies using adenoma recurrence as an end point yield negative results. Surveillance colonoscopy protects individuals in families with hereditary nonpolyposis colorectal cancer, but gastroenterologists continue to perform cancer surveillance in patients with ulcerative colitis in an inconsistent manner. Screening for colorectal neoplasia with fecal occult blood tests and flexible sigmoidoscopy is being better defined and promoted, although many now advocate direct colonoscopy screening based on increasing indirect evidence of efficacy. Better methods of treating large sessile neoplasms are being developed and evaluated, and follow-up surveillance for adenoma patients increasingly is being tailored to individual patient risk.     

普通内镜结合靛胭脂染色在鉴别瘤性与非瘤性大肠息肉中的价值

目的探讨普通内镜结合靛胭脂染色在鉴别瘤性与非瘤性大肠息肉中的价值。方法对124个大肠息肉分别行普通内镜及靛胭脂染色内镜诊断,若息肉表面呈沟槽状、脑回状或分叶状结构则定义为瘤性息肉,若表面光滑或有规则小圆点状小凹就定义为非瘤性息肉,并与组织学结果比较,比较2种内镜诊断方法鉴别瘤性与非瘤性大肠息肉的诊断准确率、特异性和敏感性。结果靛胭脂染色内镜鉴别瘤性与非瘤性大肠息肉的诊断准确率显著高于普通内镜(85.48% vs 70.16%,P<0.005)。染色内镜鉴别瘤性与非瘤性大肠息肉的敏感性和特异性分别为86.11%、84.62%,显著高于普通内镜的72.22%、67.31%(P<0.05)。结论普通内镜结合靛胭脂染色可较准确地鉴别瘤性与非瘤性大肠息肉,有助于实时指导内镜下对大肠息肉的处理方式。     

结直肠癌手术切除后患者的结肠镜检查

目的：通过对结直肠癌手术切除后患者行肠镜检查情况的分析,探讨结肠镜检查在结直肠癌患者术后随访中的应用价值。方法：回顾性分析2009年1年间结直肠癌术后行肠镜检查患者863例的临床资料。结果：由于术后粘连、肠腔狭窄和肠道准备差等原因,45例未完成结肠镜检查。结直肠癌术后局部复发23例（2.7%）,异时性癌症8例（0.9%）;结直肠息肉检出率：肿瘤性息肉为29.2%,非肿瘤性息肉为23.1%。结论：结直肠癌术后3~6个月以及1年内肠镜检查是早期发现结直肠癌局部复发和异时性病灶的重要措施。     

PillCam colon capsule endoscopy compared with colonoscopy for colorectal tumor diagnosis: a prospective pilot study

BACKGROUND AND AIMS: Colonoscopy is regarded as the gold standard for colorectal cancer (CRC) screening. PillCam capsule endoscopy could be an alternative approach for screening large populations. We report a pilot evaluation in humans of the safety, feasibility, and performance of colon capsule endoscopy compared with colonoscopy. PATIENTS AND METHODS: Patients included in this single-center comparative study had presented for screening colonoscopy or there was suspicion of polyps or CRC. The capsule was ingested in the morning. After excretion, colonoscopy was performed. Significant findings were defined either as polyps > 6 mm, or three or more polyps of any size. Colonoscopy and colon capsule endoscopy (CCE) review were performed by independent physicians. RESULTS: 41 patients (26 women), mean age 56 years (range 26 - 75) were included, and all had complete colonoscopies. Four patients were excluded due to technical problems and one could not swallow the capsule; thus, 36 patients were considered in the analysis. In six the capsule had not been expelled at 10 hours and was retrieved endoscopically. CCE identified 19 of the 25 patients (76 %) with positive findings and 10 of the 13 (77 %) with significant lesions detected by colonoscopy. CCE detected seven lesions not seen at colonoscopy and two tumors were detected by both examinations. Overall sensitivity of CCE to detect significant lesions was 77 %, specificity was 70 %, positive predictive value was 59 %, and negative predictive value was 84 %. No adverse events occurred. CONCLUSION: CCE showed promising accuracy compared with colonoscopy. This new noninvasive technique deserves further evaluation as a potential CRC screening tool.     

Preoperative evaluation of submucosal invasive colorectal cancer using a 15-MHz ultrasound miniprobe

BACKGROUND AND STUDY AIMS: Recently, it was reported that focal submucosal invasive colorectal cancer could be treated by polypectomy or endoscopic mucosal resection (EMR) because of the rarity of lymph-node metastasis. Our objective was to examine the accuracy and efficacy of a 15-MHz ultrasound miniprobe in the preoperative evaluation of the degree of submucosal invasion in colorectal cancer. PATIENTS AND METHODS: A total of 35 patients with submucosal invasive colorectal cancer who underwent ultrasonography with a miniprobe were studied prospectively. The results of this imaging were compared with the histologic findings in resected specimens. RESULTS: Although the accuracy of the miniprobe in categorizing submucosal invasion into three subclasses (SM1, invasion limited to the upper third; SM2, limited to the middle third; SM3, limited to the lower third) was low (37.1%; 13/35), the accuracy in differentiation between < or = SMI (M and SMI) and > or = SM2 (SM2, SM3, MP, and S) was 85.7 % (30/35). CONCLUSIONS: The miniprobe can be useful for therapeutic decision-making in submucosal invasive colorectal cancer.     

Benign colorectal neoplasms undetected by colonoscopy

This retrospective investigation assessed the sensitivity of colonoscopy for the detection of colonic polyps seen previously at barium enema examination. Included in the study were 77 patients with 106 polypoid lesions. Films showing lesions not subsequently seen at colonoscopy were reviewed and only those lesions with a visible point of attachment, exhibiting no movement in response to filling or change in position of the patient, and confidently diagnosed as a polyp by both reviewing radiologists were included among the 106 lesions. Sixteen lesions (15%) seen radiologically were not located colonoscopically, indicating an endoscopic sensitivity of 85%. Contrary to previous reports, most of the lesions missed endoscopically were in the left colon in regions thought to have been traversed by the instrument. The 15% false-negative rate found for colonoscopy is consistent with existing reports on colonoscopic errors and is approximately the same as the false-negative error rate for radiologic detection of colonic polyps.     

Virtual endoscopic colonography based on 3D MRI

Background: To evaluate the potential of magnetic resonance colonography (MRC) in detecting colorectal mass lesions. Methods: Twenty patients underwent MR imaging (MRI) before colonoscopy. The colon was filled with a gadolinium (0.5 mol):water mixture (1:100) under MRI control, and patients were imaged while breath-holding imaged with a three-dimensional spoiled gradient echo sequence in the prone and supine positions. Images were interactively analyzed based on the combination of multiplanar reconstruction and virtual colonoscopy by a radiologist blinded to colonoscopic findings and the patient's history. MRC interpretations were correlated with colonoscopic results. Results: Polyps smaller than 5 mm could not be identified with MRC. The sensitivity for detecting polyps of 5–10 mm was 70%, whereas mass lesions larger than 10 mm were all detected (sensitivity = 100). The sensitivity, specificity, and accuracy for identifying polyp-positive patients including the three patients with small (<5 mm) polyps were 64%, 89%, and 75%, respectively. Conclusion: Virtual colonoscopy based on MRI data is feasible and should be evaluated in a larger sample of patients.     

Barium enema examination: sensitivity in detecting colonic polyps and carcinomas

We analyzed the sensitivity of the barium enema examination in 128 patients with 191 endoscopically proven colonic polyps and 12 carcinomas, relative to patient age, indications, and the type of examination used. Seventy-seven patients (60%) had rectal bleeding, and 51 (40%) patients with 87 lesions, including six carcinomas, did not. Overall roentgenographic sensitivity was 88%, with a 93% detection rate in patients less than 70 years old as compared to 76% for older patients. Sensitivity of single- and double-contrast barium enema examination was 82% and 91%, respectively. There were similar detection rates for lesions 1 cm or more in size (91% vs 95% for single- and double-contrast examinations, respectively), but double-contrast examination was slightly better at detecting smaller polyps (88%, vs 70% for single-contrast examination). Compared to colonoscopy, which has an average reported false-negative rate of 12% in detecting neoplasms, the barium enema is similarly reliable, less costly, and safer.