Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380

BACKGROUND AND METHODS: The role of colonoscopy in screening for colorectal cancer is uncertain. At 13 Veterans Affairs Medical Centers, we performed colonoscopy to determine the prevalence and location of advanced colonic neoplasms and the risk of advanced proximal neoplasia in asymptomatic patients (age range, 50 to 75 years) with or without distal neoplasia. Advanced colonic neoplasia was defined as an adenoma that was 10 mm or more in diameter, a villous adenoma, an adenoma with high-grade dysplasia, or invasive cancer. In patients with more than one neoplastic lesion, classification was based on the most advanced lesion. RESULTS: Of 17,732 patients screened for enrollment, 3196 were enrolled; 3121 of the enrolled patients (97.7 percent) underwent complete examination of the colon. The mean age of the patients was 62.9 years, and 96.8 percent were men. Colonoscopic examination showed one or more neoplastic lesions in 37.5 percent of the patients, an adenoma with a diameter of at least 10 mm or a villous adenoma in 7.9 percent, an adenoma with high-grade dysplasia in 1.6 percent, and invasive cancer in 1.0 percent. Of the 1765 patients with no polyps in the portion of the colon that was distal to the splenic flexure, 48 (2.7 percent) had advanced proximal neoplasms. Patients with large adenomas (> or = 10 mm) or small adenomas (< 10 mm) in the distal colon were more likely to have advanced proximal neoplasia than were patients with no distal adenomas (odds ratios, 3.4 [95 percent confidence interval, 1.8 to 6.5] and 2.6 (95 percent confidence interval, 1.7 to 4.1], respectively). However, 52 percent of the 128 patients with advanced proximal neoplasia had no distal adenomas. CONCLUSIONS: Colonoscopic screening can detect advanced colonic neoplasms in asymptomatic adults. Many of these neoplasms would not be detected with sigmoidoscopy.     

One-time screening for colorectal cancer with combined fecal occult-blood testing and examination of the distal colon

BACKGROUND: Fecal occult-blood testing and sigmoidoscopy have been recommended for screening for colorectal cancer, but the sensitivity of such combined testing for detecting neoplasia is uncertain. At 13 Veterans Affairs medical centers, we performed colonoscopy to determine the prevalence of neoplasia and the sensitivity of one-time screening with a fecal occult-blood test plus sigmoidoscopy. METHODS: Asymptomatic subjects (age range, 50 to 75 years) provided stool specimens on cards from three consecutive days for fecal occult-blood testing, which were rehydrated for interpretation. They then underwent colonoscopy. Sigmoidoscopy was defined in this study as examination of the rectum and sigmoid colon during colonoscopy, and sensitivity was estimated by determining how many patients with advanced neoplasia had an adenoma in the rectum or sigmoid colon. Advanced colonic neoplasia was defined as an adenoma 10 mm or more in diameter, a villous adenoma, an adenoma with high-grade dysplasia, or invasive cancer. Classification of subjects according to the findings was based on the most advanced lesion. RESULTS: A total of 2885 subjects returned the three specimen cards for fecal occult-blood testing and underwent a complete colonoscopic examination. A total of 23.9 percent of subjects with advanced neoplasia had a positive test for fecal occult blood. As compared with subjects who had a negative test for fecal occult blood, the relative risk of advanced neoplasia in subjects who had a positive test was 3.47 (95 percent confidence interval, 2.76 to 4.35). Sigmoidoscopy identified 70.3 percent of all subjects with advanced neoplasia. Combined one-time screening with a fecal occult-blood test and sigmoidoscopy identified 75.8 percent of subjects with advanced neoplasia. CONCLUSIONS: One-time screening with both a fecal occult-blood test with rehydration and sigmoidoscopy fails to detect advanced colonic neoplasia in 24 percent of subjects with the condition.     

Wavelet method for CT colonography computer-aided polyp detection

Computed tomographic colonography (CTC) computer aided detection (CAD) is a new method to detect colon polyps. Colonic polyps are abnormal growths that may become cancerous. Detection and removal of colonic polyps, particularly larger ones, has been shown to reduce the incidence of colorectal cancer. While high sensitivities and low false positive rates are consistently achieved for the detection of polyps sized 1 cm or larger, lower sensitivities and higher false positive rates occur when the goal of CAD is to identify "medium"-sized polyps, 6-9 mm in diameter. Such medium-sized polyps may be important for clinical patient management. We have developed a wavelet-based postprocessor to reduce false positives for this polyp size range. We applied the wavelet-based postprocessor to CTC CAD findings from 44 patients in whom 45 polyps with sizes of 6-9 mm were found at segmentally unblinded optical colonoscopy and visible on retrospective review of the CT colonography images. Prior to the application of the wavelet-based postprocessor, the CTC CAD system detected 33 of the polyps (sensitivity 73.33%) with 12.4 false positives per patient, a sensitivity comparable to that of expert radiologists. Fourfold cross validation with 5000 bootstraps showed that the wavelet-based postprocessor could reduce the false positives by 56.61% (p <0.001), to 5.38 per patient (95% confidence interval [4.41, 6.34]), without significant sensitivity degradation (32/45, 71.11%, 95% confidence interval [66.39%, 75.74%], p=0.1713). We conclude that this wavelet-based postprocessor can substantially reduce the false positive rate of our CTC CAD for this important polyp size range.     

Korean type 2 diabetes patients have multiple adenomatous polyps compared to non-diabetic controls

We tested the correlation between diabetes and aggressiveness of colorectal polyps in diabetic patients and matched non-diabetic controls. We retrospectively studied 3,505 type 2 diabetes (T2DM) patients without gastrointestinal symptoms who underwent colonoscopy for colorectal cancer at Samsung Medical Center, Seoul, Korea from August 1995 to August 2009. We matched 495 non-diabetic subjects with colon polyps to the diabetic patients in whom polyps were detected by year of colonoscopy, age, sex and body mass index (BMI). Among the 3,505 T2DM patients screened, 509 were found to have 1,136 colon polyps. Those with diabetes had a greater proportion of adenomatous polyps (62.8% vs 53.6%) compared to the control. Multivariate logistic regression analysis identified DM, male gender, age and BMI as independent risk factors for multiple polyps (more than three polyps). Polyp multiplicity in diabetic patients was significantly associated with male gender (OR 2.360, P = 0.005), age (OR 1.033, P = 0.005) and BMI (OR 1.077, P = 0.028). Neither aspirin nor metformin use affected either size or number of polyps in diabetic patients. Male patients older than 65 yr with T2DM and BMI greater than 25 have increased risk for multiple adenomatous polyps and should be screened with colonoscopy to prevent colorectal cancer.     

Risk of advanced proximal neoplasms in asymptomatic adults according to the distal colorectal findings

BACKGROUND AND METHODS: The clinical significance of a distal colorectal polyp is uncertain. We determined the risk of advanced proximal neoplasia, defined as a polyp with villous features, a polyp with high-grade dysplasia, or cancer, among persons with distal hyperplastic or neoplastic polyps as compared with the risk among persons with no distal polyps. We analyzed data from 1994 consecutive asymptomatic adults (age, 50 years or older) who underwent colonoscopic screening for the first time between September 1995 and December 1998 as part of a program sponsored by an employer. The location and histologic features of all polyps were recorded. Colonoscopy to the level of the cecum was completed in 97.0 percent of the patients. RESULTS: Sixty-one patients (3.1 percent) had advanced lesions in the distal colon, including 5 with cancer, and 50 (2.5 percent) had advanced proximal lesions, including 7 with cancer. Twenty-three patients with advanced proximal neoplasms (46 percent) had no distal polyps. The prevalence of advanced proximal neoplasia among patients with no distal polyps was 1.5 percent (23 cases among 1564 persons; 95 percent confidence interval, 0.9 to 2.1 percent). Among patients with distal hyperplastic polyps, those with distal tubular adenomas, and those with advanced distal polyps, the prevalence of advanced proximal neoplasia was 4.0 percent (8 cases among 201 patients), 7.1 percent (12 cases among 168 patients), and 11.5 percent (7 cases among 61 patients), respectively. The relative risk of advanced proximal neoplasia, adjusted for age and sex, was 2.6 for patients with distal hyperplastic polyps, 4.0 for those with distal tubular adenomas, and 6.7 for those with advanced distal polyps, as compared with patients who had no distal polyps. Older age and male sex were associated with an increased risk of advanced proximal neoplasia (relative risk, 1.3 for every five years of age and 3.3 for male sex). CONCLUSIONS: Asymptomatic persons 50 years of age or older who have polyps in the distal colon are more likely to have advanced proximal neoplasia than are persons without distal polyps. However, if colonoscopic screening is performed only in persons with distal polyps, about half the cases of advanced proximal neoplasia will not be detected.     

色素内镜在近端结肠息肉筛查中的临床应用研究

目的 对比常规肠镜与色素内镜对近端结肠（盲肠至结肠肝曲）息肉检出率的差异。方法 选取我院2015年7月~2017年7月行肠镜检查患者200例,随机分为常规内镜组和色素内镜组（近端结肠染色）,每组100例。统计患者的近端结肠病变检出情况（数量、大小、形态及病理）,对比两组近端结肠息肉检出率、近端结肠退镜观察时间。结果 两组共检出息肉47个,色素内镜组近端结肠息肉检出率为21.00%,高于常规内镜组的10.00%,差异有统计学意义（P＜0.05）。色素内镜组直径＜5 mm息肉数量高于常规内镜组,差异有统计学意义（P＜0.05）。两组腺瘤、高危腺瘤、扁平腺瘤检出个数以及近端结肠退镜观察时间比较,差异无统计学意义（P＞0.05）。结论 色素内镜可显著提高直径＜5 mm近端结肠息肉的检出率,以及腺瘤、高危腺瘤和扁平腺瘤的检出率。     

Significance of rectosigmoid polyp as a predictor of proximal colonic polyp

The association between rectosigmoid polyps and polyps in the more proximal colon is still a matter of debate, and the need for colonoscopy in patients with rectosigmoid polyps that are detected by flexible sigmoidoscopy is controversial. The aim of this study was to determine whether or not certain characteristics of rectosigmoid polyps are associated with the presence and characteristics of proximal colonic polyps. Seven hundred and twenty-eight patients who underwent total colonoscopy between October 1995 and June 1998 and who had colorectal polyps were retrospectively analyzed. Patients with inflammatory bowel diseases, familial adenomatous polyposis, or any advanced cancer were excluded. The odds ratio (OR) and 95% confidence interval (CI) of prevalence of proximal colonic polyps according to the patients age and sex, as well as the characteristics of rectosigmoid polyps, were calculated. Advanced adenoma was defined as an adenoma larger than 10 mm or an adenoma of any size with villous component, high-grade dysplasia or invasive carcinoma. Among 728 patients with colorectal polyps, 356 patients (48.9%) had polyps only in the rectosigmoid region, 193 patients (26.5%) had polyps only in the proximal colon, and 179 patients (24.6%) had polyps in both the rectosigmoid and proximal colon. In 535 patients with rectosigmoid polyps, the prevalence of proximal colonic polyps, neoplastic polyps and advanced adenomas were 33.4%, 27.3% and 2.9%, respectively. The prevalence of proximal colonic polyps in patients with rectosigmoid polyps was found to be significantly related to the male gender and elderly patients, in addition to the neoplastic histology of the rectosigmoid polyps. However, the prevalence of the proximal colonic polyps was not related to the size, number and shape of rectosigmoid polyps. In 179 patients with both rectosigmoid and proximal colonic polyps, the characteristics of proximal colonic polyps such as size, number and shape were similar to those of rectosigmoid polyps. We recommend total colonoscopic examination in all patients with rectosigmoid adenomas, regardless of the size, number, and shape, especially in elderly males.     

CT结肠造影二维和三维图像评价结肠病变的优势与不足

背景：随着多层探测器螺旋CT的广泛应用,已使胃肠道等空腔脏器的CT检查成为可能。 目的：通过结肠充气CT结肠造影扫描,评价二维和三维图像对结肠病变检出的有效性以及各自的优势和不足。 方法：38例患者导泻后经肛门注入适量空气,行多层螺旋CT扫描,再经工作站对扫描获得的容积数据进行后处理,获得多平面重组的冠、矢状面图像、表面重建、透明重建、仿真内窥镜和管腔展开图像,由2位有经验的影像科医师对上述图像进行分析,评价结肠病变的性质、位置、大小和肠外表现,并与电子结肠镜或手术病理结果对照。 结果和结论：除1例为家族性息肉病外,其余37例患者共检出17枚息肉、20个结肠肿块和5例结肠炎性病变。对3种类型病变的检出率,多平面重组分别为82%、100%和100%;仿真内窥镜分别为100%、100%和80%;表面重建分别为41%,90%和40%;透明重建分别为47%、90%和40%。管腔展开技术对所检病变的显示率达100%。二维图像可对结肠病变准确定位并精确测量大小,在显示结肠病变肠外表现方面的优势明显,仿真内窥镜的敏感性较高,管腔展开技术又进一步避免了检查盲区,表面重建和透明重建在显示结肠全景方面价值较高。     

The Risk of Colorectal Neoplasia in Patients with Gallbladder Diseases

Cholecystectomy is associated with an increased risk of colorectal cancer, but little is known about the relationship between gallbladder disease and colorectal adenoma. Gallbladder polyps and colorectal neoplasia (CRN) share several risk factors such as obesity, diabetes and metabolic syndrome, which might account for their association. In this study, we investigated whether asymptomatic patients with gallbladder disease are at increased risk of CRN and identified the factors to their association. The study population consisted of 4,626 consecutive, asymptomatic individuals drawn from a prospective health check-up cohort who underwent both ultrasonography and colonoscopy screening. The prevalence of CRNs in patients with gallbladder polyps or gallstones was significantly higher than that in the control group (32.1% vs. 26.8%; P = 0.032, 35.8% vs. 26.9%; P = 0.020). A multivariate regression analysis showed that gallbladder polyps were an independent risk factor for CRN [adjusted odds ratio (OR): 1.29; 95% confidence interval (CI); 1.03-1.62] whereas gallstones were not (adjusted OR: 1.14; 95% CI: 0.79-1.63). The adjusted OR for the risk of CRN was 1.12 for gallbladder polyps < 5 mm (95% CI, 0.85-1.46) and 1.79 for gallbladder polyps ≥ 5 mm (95% CI, 1.15-2.77). The prevalence of CRN increased with increasing polyp size (P trend = 0.022). Our results suggest that colorectal neoplasia is significantly related to gallbladder polyps, especially those ≥ 5 mm.

Graphical Abstract

相似文献   

Fundic gland polyps (Elster's cysts) of the gastric mucosa. A marker for colorectal epithelial neoplasia?

The results of several retrospective studies allow us to conclude that the detection of fundic gland polyps (Elster's cysts) is associated with an increased incidence of colorectal tumors. In this survey, we present the results of a prospective study investigating such a possible relationship. A total of 144 patients were investigated, of whom 80 had fundic gland polyps of the gastric corpus mucosa. Sixty-four of these patients underwent a colonoscopy, whereas the other 64 patients belonged to a sex- and age-matched control group with no fundic gland polyps. In the group with known fundic gland polyps, colorectal neoplasias were found in 29 (45.3%) patients. Eight of these patients had (12.5%) adenocarcinomas, 3 (4.7%) had high-grade intraepithelial neoplasia, and 18 (28.1%) had tubular adenomas. In one patient, a synchronous carcinoma of the rectum and the colon was detected. In comparison, 6 patients of the control group (9.3%) developed tubular adenomas and 9 (14.1%) had hyperplastic polyps of the colonic and rectal mucosa. Our results suggest that it is necessary to conduct a careful diagnostic work-up of the colon in patients with gastric fundic gland polyps.     

Diagnosis and staging of colonic tumors by conventional abdominal sonography as compared with hydrocolonic sonography.

BACKGROUND. Ultrasonic examination has become increasingly important in the diagnosis of diseases of the gastrointestinal tract. In neoplastic diseases of the large intestine, however, the diagnostic value of conventional transabdominal sonography is limited. The purpose of this investigation was to determine whether the evaluation and staging of colonic tumors would be improved by the retrograde instillation of water into the colon in a procedure called hydrocolonic sonography. METHODS. Three hundred patients were examined in a prospective study in which both conventional transabdominal sonography and transabdominal hydrocolonic sonography were performed before the diagnosis was verified by colonoscopy. The indication for the examinations was abdominal pain, diarrhea, weight loss, or the presence of occult blood in a stool specimen. RESULTS. With the instillation of water into the colon, it was possible to display the colon sonographically from the rectosigmoid transition to the cecum in 97 percent of the patients examined. In addition to permitting the evaluation of the colonic lumen, the procedure allowed the five layers of the colonic wall and the connective tissue surrounding the colon to be examined in detail. Only 9 of 29 carcinomas were diagnosed by conventional abdominal sonography (31 percent), whereas hydrocolonic sonography permitted the diagnosis of 28 (97 percent). No polyps could be detected by conventional abdominal sonography, whereas hydrocolonic sonography permitted the diagnosis of 38 of 42 polyps greater than or equal to 7 mm (91 percent) and 3 of 12 polyps less than 7 mm (25 percent). In addition, detailed evaluation of the structure of the bowel wall with hydrocolonic sonography permitted a more precise staging of colonic tumors. CONCLUSIONS. Hydrocolonic sonography, a new diagnostic procedure, can facilitate the diagnosis and staging of colonic tumors.     

Incomplete colonoscopy in patients with occlusive colorectal cancer: usefulness of CT colonography according to tumor location

PURPOSE: We sought to evaluate the clinical usefulness of CT colonography (CTC) after incomplete conventional colonoscopy (CC) for occlusive colorectal cancer (CRC) according to the tumor location. MATERIALS AND METHODS: Seventy-five patients with occlusive CRC underwent subsequent CTC immediately after incomplete CC. Fifty-nine patients had distal CRC and 16 had proximal colon cancer. Experienced radiologists prospectively analyzed the location, length, and TNM staging of the main tumor. The colorectal polyps in the remaining colorectum and additional extraluminal findings were also recorded. Sixty-seven patients underwent colorectal resection. We retrospectively analyzed the surgical outcome and correlated CTC and CC findings. RESULTS: The overall accuracies of tumor staging were: T staging, 86%; N staging (nodal positivity), 70% (80%); and intra-abdominal M staging, 94%. Additional colonic polyps were found in 23 patients. Six synchronous carcinomas were detected (9%); three in the proximal colon and three in the distal colon of occlusion. Clinically significant localization errors at CC were noted in 8 patients (12%, 5 proximal colon cancers and 3 distal CRCs) and were corrected by CTC. After CTC, the surgeons modified the initial surgical plan in 11 cases (16%). CONCLUSION: In occlusive CRC, CTC is not only useful in the evaluation of the proximal bowel, but can also provide surgeons with accurate information about staging and tumor localization. CTC is recommended when endoscopists encounter occlusive CRC, regardless of tumor location.     

Comprehensive evaluation of colorectal polyps in specimens from endoscopic biopsies

Modern evaluation of specimens from biopsies of colorectal polyps has become increasingly complex because of tremendous progress in the understanding of colorectal neoplasia. Although pathologists are generally familiar with the basic handling of carcinoma in the setting of polypectomies or resections, the comprehensive evaluation of specimens from biopsies of colorectal polyps obtained with forceps is far from intuitive and has yet to be reviewed. Comprehensive evaluation requires always addressing several key issues, even when dealing with seemingly routine cases. These issues include taking further action when initial sections lack polyps, accurately quantitating polyps, accurately classifying polyps, determining whether thresholds are met for considering conditions at high risk for carcinoma, detecting incidental findings other than polyps, and determining which incidental findings are clinically significant. In particular, polyposis with attenuated phenotype or Lynch syndrome may be clinically occult, and the possibility of these entities should always be kept in mind, regardless of age or history. Ancillary studies performed immediately on carcinoma that is detected at biopsy guides surgery, guides medical therapy, prognosticates, provides evidence for hereditary neoplasia, and guides surveillant colonoscopy for the family.     

Double-contrast barium enema study with computed radiography: assessment in detection of colorectal polyps

Feasibility and diagnostic performance of digital radiography in gastrointestinal imaging have not been fully investigated. We performed double-contrast barium enema study with computed radiography (CR-DCBE) on a routine basis, and the efficacy of this system for detection of colorectal polyps was investigated. The files of 76 patients, who had undergone both CR-DCBE and colonoscopy, were reviewed by two observers who were blinded to the colonoscopic findings. The radiation dose of CR-DCBE was reduced to 50% of conventional film-screen system. By using colonoscopic findings as a reference, the sensitivity and positive predictive value for colorectal polyps were 66% to 71% and 32% to 41%, respectively. There was no significant interobserver difference. The use of postprocessing with gray-scale reversal and edge enhancement did not significantly improve the results. The sensitivity for polyps smaller than 1 cm was comparable with published data of conventional filmscreen systems. Our preliminary results show that CR-DCBE has an acceptable sensitivity for detection of colorectal polyps. It is suggested that the use of CR is a promising approach to digital gastrointestinal radiography.     

Risk Factors for Recurrent High-Risk Polyps after the Removal of High-Risk Polyps at Initial Colonoscopy

Purpose

Colonoscopic polypectomy and surveillance are important to prevent colorectal cancer and identify additional relative risk factors for adequate surveillance. In this study, we evaluated risk factors related to recurrent high-risk polyps during the surveillance of patients with high-risk polyps.

Materials and Methods

We included 434 patients who had high-risk polyps (adenoma ≥10 mm, ≥3 adenomas, villous histology, or high-grade dysplasia) on the baseline colonoscopy and underwent at least one surveillance colonoscopy from 2005 to 2011 at Severance Hospital. Data regarding patient characteristics, bowel preparation and polyp size, location, number, and pathological diagnosis were retrospectively collected from medical records. Patients with recurrent high-risk polyps were compared with patients with low-risk or no polyps during surveillance.

Results

Patients were predominantly male (77.4%), with a mean age of 61.0±8.6 years and mean follow-up of 1.5±0.8 years. High-risk polyps recurred during surveillance colonoscopy in 51 (11.8%) patients. Results of multivariate analysis showed that male gender, poor bowel preparation, and a larger number of adenomas were independent risk factors for recurrent high-risk polyps (p=0.047, 0.01, and <0.001, respectively). Compared with high-risk polyps found during initial colonoscopy, high-risk polyps on surveillance colonoscopy had higher proportions of small adenomas, low-risk pathology, and fewer adenomas overall, but there was no difference in location.

Conclusion

Male patients and those with poor bowel preparation for colonoscopy or higher numbers of adenomas were more likely to experience recurrent high-risk polyps.     

Genetic alterations and epithelial dysplasia in juvenile polyposis syndrome and sporadic juvenile polyps.

Juvenile polyps are regarded as hamartomatous polyps and occur in sporadic and familial syndromic settings. There is increased risk of gastrointestinal neoplasia in patients with juvenile polyposis syndrome, but the molecular mechanisms are not known. We therefore studied 78 colorectal juvenile polyposis from 12 patients with juvenile polyps syndrome and 34 sporadic juvenile polyps for epithelial dysplasia and genetic changes associated with colorectal neoplasia. Dysplasia occurred in 31% of syndromic juvenile polyps but not in sporadic juvenile polyps (P < 0.0001). Topographic control of proliferation and expression of the cyclin-dependent kinase inhibitor p21(WAFI/CIP1) seen in native colorectal epithelium was lost in 79% of dysplastic juvenile polyps and in 8% of nondysplastic juvenile polyps (P < 0.000001). Somatic mutations in the adenomatous polyposis coli (APC) gene were demonstrated in 50% of dysplastic juvenile polyps (3 of 6) but not in any of 16 juvenile polyps without dysplasia (P = 0.01). Both sporadic and syndromic juvenile polyps had K-ras mutations (14%) and there was no relationship to dysplasia. p53 gene product overexpression identified by immunohistochemical staining occurred rarely in dysplastic juvenile polyps (2 of 24, 8%). Our results indicate that the multiple genetic alterations involved in usual colorectal neoplasia also play a role in neoplastic transformation of juvenile polyps, predominantly in juvenile polyposis syndrome.     

Clinical aspects of MR colonography as a diagnostic tool

Since first described in 1997, MR colonography (MRC) has since been labelled as a promising new, non-invasive technique for examining the colon. At present time, the examination is ready to be implemented as a supplement to incomplete colonoscopy or preoperative colonic evaluation. Furthermore, MRC seems to have a great potential in the screening for colorectal cancer, since detection of polyps and polypectomy might reduce on the incidence of colorectal cancer. This is speculated in the adenoma-carcinoma sequence theory, which states that most cancers evolve from polyps over a long period and that polypectomy might be curative. Colonoscopy remains the gold standard for full colon evaluation. However, the result of our studies can justify clinical use of MRC on selected indications, e.g. in the cases where colonoscopy is incomplete or technically difficult. Since up to 54% of all preoperative colon evaluations in patients with colorectal cancer and up to 17-23% of regular colonoscopies are incomplete, the clinical potential of MRC is evident. Furthermore, in our studies we have shown the insufficiency of preoperative colonic evaluation by CC. In addition, considering the invasiveness, the serious complications (perforation, bleeding, death) and the lack of patient acceptance in colonoscopy, the need for a safe, patient friendly alternative examination with high sensitivity, is clear. In conclusion, in the three studies that made up this PhD thesis, we have shown: that there are some flaws to the present gold standard of colonic evaluation; that there is an increased morbidity and mortality in the group of patients with missed SC; that patients have a preference for MRC and for fecal tagging compared to CC and bowel purgation and that there is a potential gain in doing preoperative colonic evaluation with MRC on all patients with rectal- or sigmoid colon cancer.     

Inappropriate colonoscopic surveillance of hyperplastic polyps

Colonoscopic surveillance of hyperplastic polyps alone is controversial and may be inappropriate. The colonoscopy surveillance register at a university teaching hospital was audited to determine the extent of such hyperplastic polyp surveillance. The surveillance endoscopy records were reviewed, those patients with hyperplastic polyps were identified, their clinical records were examined and contact was made with each patient. Of the 483 patients undergoing surveillance for colonic polyps 113 (23%) had hyperplastic polyps alone on last colonoscopy. 104 patients remained after exclusion of those under appropriate surveillance. 87 of the 104 patients (84%) were successfully contacted. 37 patients (8%) were under appropriate colonoscopic surveillance for a significant family history of colorectal carcinoma. 50 (10%) patients with hyperplastic polyps alone and no other clinical indication for colonoscopic surveillance were booked for follow up colonoscopy. This represents not only a budgetary but more importantly a clinical opportunity cost the removal of which could liberate valuable colonoscopy time for more appropriate indications.     

结直肠活检HGCIN与手术切除病理标本对比研究

目的：分析结直肠高级别上皮内瘤变(high grade colorectal intraepithelial neoplasia,HGCIN)术前结肠镜活检与手术切除病理标本的诊断效果。方法：选取本院2012年4月至2015年4月收治的HGCIN患者52例,所有病例均接受术前结肠镜活检检查以及手术切除标本病理检查,回顾性分析两种诊断方式的临床特点,总结结直肠HGCIN合理诊断方式,并探讨术前活检与手术切除病理检查的差异原因。结果：52例患者术前结肠镜活检均确诊为HGCIN,手术切除标本病理检验诊断为HGCIN共4例,同术前诊断的符合率为7.7%(4/52),另48例患者均诊断为腺癌,术前活检与术后病理检验结果比较存在统计学差异(P<0.05);同时,直肠位置病变误诊率约为97.2%(35/36),结肠位置病变误诊率约为81.3%(13/16),直肠病变误诊机率显著高于结肠,具有统计学意义(P<0.05)。结论：结直肠HGCIN术前活检与手术切除标本病理检查的差异性较为显著,临床针对疑似病理务必严密评估其病变分化程度等相关情况,积极同病理医师进行沟通,以缓解术前误诊情况,确保给予患者更为合理的临床诊治方案。     

结直肠腺瘤性息肉诊治新进展

很多结直肠癌都起源于结直肠腺瘤性息肉.结肠镜检查是发现腺瘤性息肉的首选方法.结肠镜技术的进步提高了腺瘤性息肉的检出率和诊断准确率.腺瘤性息肉的治疗包括息肉切除、术后随访以及药物治疗.肠镜下息肉切除术安全有效,已基本取代了传统的开腹手术.但息肉切除术后的随访间期和药物治疗方面尚存争议.