Clinicopathologic Features of Colorectal Polyps in Shahid Beheshti University of Medical Sciences (SBMU)

Aim: This study was designed to report epidemiologic findings of polyps in Iranian patients, and predict histology of polyp regarding to demographic and colonoscopic findings. Background: Classification of colorectal polyps had been revised in the past two decades and there is a need for polyp categorization in the Iranian Health System. Patients and methods: In this retrospective study, the medical records of patients with colonoscopic diagnosis of polyp in pathology departments of SBMU affiliated teaching hospitals were reviewed. Patient’s slides evaluated and demographics findings were assessed. The anatomical location, macroscopic appearance including size and histological assessment of all polyps were recorded. Results: From total number of 1106 polyps (detected in 862 patients), adenomatous polyps (638 [57.7%]) were the most prevalent findings, followed by colon mucosal tag (184[16.6%]), hyperplastic and serrated polyps (122[11%]), inflammatory polyps (110[9.9%]), hamartomatous (21[1.9%]), and malignant lesions (13[1.2%]). Multivariate logistic regression showed age (each one year increasing age; odds ratio [OR] = 1.026, 95%confidence interval [CI] = 1.016–1.036, p < 0.0001), location of polyp (right colon; OR = 1.905, 95%CI = 1.366–2.656, p < 0.0001), and polyp size of 5-10 mm (OR = 1.662, 95%CI = 1.214–2.276, p = 0.002), and polyp size of >10 mm (OR = 2.778, 95%CI = 1.750–4.411, p< 0.0001) were independently associated with neoplastic polyps. Also, polyp size of >10 mm (OR= 2.613, 95%CI= 1.083-6.307, p=0.033), tubulovillous pattern of polyp (OR= 3.508, 95%CI= 1.666-7.387, p=0.001) and villous pattern of polyp (OR= 10.444, 95%CI= 4.211-25.905, p     

Computed tomographic colonography (CTC): Possibilities and limitations of clinical application in colorectal polyps and cancer

Colorectal cancer is the second leading cause of cancer-related deaths in Europe and the United States. Most colorectal cancers develop from adenomatous polyps over a number of years. Early detection of polyps eliminates the risk of subsequent carcinomas. Computed tomographic (CT) colonography is a diagnostic technique detecting colorectal neoplasms. With the introduction of multidetector-row computed tomography (MD-CT), CT colonography (CTC) has gained influence as a new diagnostic tool in early detection of colonic pathologies by acquiring volumetric CT data sets of the abdomen. This volumetric data is analyzed using CTC workstations, which provide an interactive display of 2D and 3D images of the colon. In several studies, CTC revealed a high accuracy (sensitivity/patient: 83-100% and specificity/patient: 93-100%) in detecting pathological colonic changes. Furthermore, CTC is an excellent diagnostic technique for the evaluation of patients with incomplete conventional colonoscopy and allows the assessment of extracolonic abdominal and pelvic organs. In this article, the status of CT colonography as a method of detecting colonic polyps and colorectal carcinomas using single- and multidetector-row CT will be reviewed.     

Monitoring of Tumor Promotion and Progression in a Mouse Model of Inflammation-Induced Colon Cancer with Magnetic Resonance Colonography

Early detection of precancerous tissue has significantly improved survival of most cancers including colorectal cancer (CRC). Animal models designed to study the early stages of cancer are valuable for identifying molecular events and response indicators that correlate with the onset of disease. The goal of this work was to investigate magnetic resonance (MR) colonography in a mouse model of CRC on a clinical MR imager. Mice treated with azoxymethane and dextran sulfate sodium were imaged by serial MR colonography (MRC) from initiation to euthanasia. Magnetic resonance colonography was obtained with both T1- and T2-weighted images after administration of a Fluorinert enema to remove residual luminal signal and intravenous contrast to enhance the colon wall. Individual tumor volumes were calculated and validated ex vivo. The Fluorinert enema provided a clear differentiation of the lumen of the colon from the mucosal lining. Inflammation was detected 3 days after dextran sulfate sodium exposure and subsided during the next week. Tumors as small as 1.2 mm³ were detected and as early as 29 days after initiation. Individual tumor growths were followed over time, and tumor volumes were measured by MR imaging correlated with volumes measured ex vivo. The use of a Fluorinert enema during MRC in mice is critical for differentiating mural processes from intraluminal debris. Magnetic resonance colonography with Fluorinert enema and intravenous contrast enhancement will be useful in the study of the initial stages of colon cancer and will reduce the number of animals needed for preclinical trials of prevention or intervention.     

Helicobacter pylori infection is associated with colon adenomatous polyps detected by high-resolution colonoscopy

Helicobacter pylori (H. pylori) is associated with the development of cancer in the stomach, but both positive and negative associations were reported with colorectal neoplasia. We sought to determine whether H. pylori is associated with colon neoplasia in Japanese population. We examined 332 patients who underwent routine high-resolution total colonoscopy and serologic testing for IgG antibodies agonist H. pylori. Subjects who received cyclooxygenase-2 inhibitors or previous eradication therapy and those with borderline titer levels were excluded from data analysis (n = 27). Seronegative control subjects were from the same study population to maximize the representativeness. There were no significant differences in age and gender between the 2 patient groups. A significant increase in the incidence of adenomatous polyps (p < 0.0001) and decrease in normal colonoscopic findings (p < 0.0005) were observed in seropositive patients than those seronegative. Our study indicates an etiological link of H. pylori infection to colorectal neoplasia and the need of routine colonoscopy in seropositive patients.     

CT Colonography - Towards Applications for Colorectal Cancer Screening

Three-dimensional (3D) imaging of the large intestine is globally called computed tomography colonography(CTC). CTC has been intensively investigated for application in colorectal cancer screening in Western countriesand with the advent of multi-slice CT (MSCT), which provides effective high resolution in 3D CT images, thediagnostic use of CT for colorectal lesions has become a concept widely accepted throughout the world. Computeraideddetection (CAD) for colorectal polyps using digital CT image data and digital pre-processing are alsoadvancing in the West. Compared with colonoscopy, which depends largely on the skill of the performer, CTCproduces objective and reproducible diagnostic images and presents a high probability of standardizingexamination protocols. Development of effective systems for screening colorectal lesions is expected, leveragingthe excellent processing capability of MSCT to enhance 3D visualization and allow efficient detection.     

CT colonography (virtual colonoscopy) for the detection of colorectal polyps and neoplasms. current status and future developments

Computed tomography colonography (CTC) is a new, rapidly developing non-invasive CT technique used to detect colonic polyps and cancers. It employs two- (2D) and three-dimensional (3D) images of the colon in order to display neoplastic lesions. Clinical trials demonstrate promising results for the detection of polyps and cancers greater than or equal to 10 mm in size. Our purpose is to describe the technique of CT colonography, review recent published trials of CT colonography, and elucidate current clinical applications. Continuing technical innovations such as multidetector CT, computer-aided diagnosis, new image display techniques and faecal tagging promise to improve the performance and patient acceptance of CT colonography in the future.     

The Role of CT Colonography as a Screening Tool for Colorectal Cancer

Most colorectal cancers (CRC) are preventable through screening and polyp removal; however, CRC remains fixed as the second leading cause of cancer mortality in the USA. This is largely due to suboptimal screening participation. This review of current literature explores the use of CT colonography (CTC), also known as virtual colonoscopy, as another option for CRC screening. Relevant recent research topics include exploring the elimination of pre-procedure colon cleansing, the extension of recommended CTC screening intervals, the implications of extracolonic findings, and the significance of CTC radiation dose in a benefit/risk analysis. Peer-reviewed literature supports CTC as a viable option to safely screen average and moderate risk patients for CRC with polyps and cancer detection rates comparable to optical colonoscopy. CTC has the potential to raise CRC screening rates in population health management efforts.     

786例大肠腺瘤性息肉的癌变特征

目的:探讨大肠腺瘤性息肉的癌变特征.方法:对6 144例因有下消化道症状患者行结肠镜检查,记录大肠息肉患者的临床表现以及年龄、性别等资料,对大肠腺瘤性息肉的发生率、内镜下表现、病理类型进行分析.结果:1)结肠腺瘤性息肉占息肉患者总数的41.72%,男性占55.34%,女性占44.66%;年龄＞60岁患者占69.72%.临床症状中便血占66.28%.分布于左半结肠患者显著多于右半结肠患者(P＜0.001);2)重度不典型增生和癌变息肉直径＞2cm者占79.73%,分布于左半结肠患者也显著多于右半结肠患者(P＜0.0001).重度不典型增生和癌变率在腺瘤性息肉显著高于炎性息肉(P＜0.001);且在三种腺瘤性息肉间存在显著差异(P＜0.001).结论:结肠镜检查大肠腺瘤性息肉的检出率较高,临床症状以便血最多.其中重度不典型增生和癌变息肉具有一定的结肠镜下特征表现并且和息肉的病理类型密切相关.     

CT结肠镜诊断结直肠肿瘤和息肉准确性的系统评价

目的:系统评价CT结肠镜用于结直肠肿瘤和息肉诊断的临床价值。方法:通过计算机检索及手工查阅,全面收集CT结肠镜用于结直肠肿瘤和息肉诊断的中英文文献,按纳入与排除标准筛选文献并提取纳入研究中有关准确度的数据,根据QUADAS条目进行质量评价,采用Me-ta Disc 1.4软件检验研究间的异质性并进行Meta分析。结果:最终纳入英文文献22篇,中文文献0篇。异质性检验结果为Spearman相关系数=0.406,P=0.244,提示阈值效应引起的异质性较小,但是存在其他因素导致的异质性,按随机效应模型进行Meta分析。CTC结肠镜诊断结直肠肿瘤和息肉的敏感度和特异度分别为69%和83%,而且诊断的敏感度和特异度随着肿物大小的增加而增加,分别为62%~81%和90.1%~92.4%。结论:用CT结肠镜诊断结直肠肿瘤和息肉具有很高的特异性,但其敏感度波动范围很大。     

CT colonography in detection of colorectal carcinoma

BACKGROUND: Diagnostic methods used in screening and detecting colorectal carcinoma are digitorectal examination, faecal occult blood testing, sigmoidoscopy, DNA stool analysis, barium enema, colonoscopy, and as of recently CT colonography. The aim of this study was to establish diagnostic accuracy and comfort of CT colonography compared to colonoscopy and barium enema. PATIENTS AND METHODS.: We included 231 patients in the prospective study. For all patients CT colonography and barium enema followed by colonoscopy were performed. After the procedures a comfort assessment was done in all patients. Diagnostic positive results were verified by the pato-histological examination. Sensitivity, specificity, positive predicative value (PPV) and negative predicative value (NPV) were calculated for each procedure. RESULTS: With CT colonography, barium enema and colonoscopy 95 lesions were found, 56 (59%) of them were tumours and 39 (41%) were polyps. Among polyps pato-histology revealed 34 adenomas, 3 tubulovillous adenomas and 2 lipomas, among tumours there were 55 adenocarcinomas and 1 lymphoma. Results showed CT colonography sensitivity to polyps to be 89.7%, barium enema 48.7%, and colonoscopy 94.9%. Sensitivity to tumours of CT colonography and colonoscopy was 100% and of barium enema 94.6%. Specificities and PPV were 100% in all procedures. The comfort assessment showed CT colonography as the far most comfortable out of three procedures.     

16层螺旋CT低剂量结肠成像对结肠新生物的检测价值

目的探讨16层螺旋CT低剂量结肠成像对结肠新生物的检测价值。方法收集103例既作CT低剂量结肠成像同时又有传统结肠镜检查资料的病例（两种检查在1周内完成）,记录结肠新生物的有无、位置、大小及形态,统计每一组病例CT检查结果的敏感性、特异性、阳性预测值及阴性预测值。记录每1个病例的放射剂量加权指数。结果CT低剂量结肠成像正确地检出全部11个结肠癌灶（敏感性100.0%）,68个息肉（敏感性70.0%）。对10mm以上（含10mm）,6～9mm,5mm以下（含5mm）息肉检出的敏感性分别为93.8%（15/16）,91.7%（22/24）,54.4%（31/57）。平均CT剂量加权指数为4.0mGy。结论16层螺旋CT低剂量结肠成像明显降低了患者的放射剂量,同时对6mm以上息肉检测有较高的敏感性。     

Tobacco smoking and colorectal hyperplastic and adenomatous polyps.

Colorectal adenomas and possibly some hyperplastic polyps are precursors of colorectal cancer. Tobacco use is associated in epidemiologic studies with these polyps, although links between smoking and colorectal cancer are less consistent. To characterize the role of tobacco in early colorectal carcinogenesis, we compared tobacco use among 4,383 subjects with histologically verified benign (hyperplastic or adenomatous) polyps of the distal colon (descending colon, sigmoid, and rectum) with tobacco use among 33,667 subjects who were endoscopy negative for distal colon tumors, in the screening arm of the Prostate, Lung, Colorectal, and Ovarian Trial, a randomized trial of flexible sigmoidoscopy. Risks, estimated by the odds ratio (OR), associated with current cigarette use were OR = 4.4 [95% confidence interval (95% CI), 3.7-5.2] for hyperplastic polyps only, OR = 1.8 (95% CI, 1.5-2.1) for adenomas only, and OR = 6.2 (95% CI, 4.7-8.3) for subjects with both hyperplastic and adenomatous polyps concurrently. Effects were weaker among ex smokers; the smoking-associated ORs remained consistently higher for hyperplastic polyps. This pattern was also seen in relation to cigarettes smoked per day, smoking duration, and pack-years. Tobacco-associated risks for multiple polyps were also stronger when hyperplastic disease was involved. In conclusion, tobacco use, particularly recent use, increases risk for both adenomatous and hyperplastic polyps, but the risks are substantially greater for hyperplastic lesions.     

Changing site distribution of Japanese colorectal cancer

To clarify the time trends in the characteristics of colorectal cancer, we investigated 1,286 Japanese patients with colorectal cancer who underwent a resection of the disease between 1972 and 1995 at our hospital. Based on our findings, this carcinoma tended to shift to the more proximal colon in the second 11-year period in comparison to the first 11-year period (P=0.0001). This tendency was also found in elderly patients (P=0.0001), but not in young ones. These findings thus suggest the need for targeted examinations for the early detection of the proximal colon cancer, especially in the elderly.     

Utility of computed tomographic colonography in surveillance for hereditary nonpolyposis colorectal cancer syndrome

Computed tomographic colonography (CTC) is suggested to be an alternative to colonoscopy as a surveillance tool in subjects with a high risk for colorectal cancer (CRC). To evaluate the utility of CTC we successively examined 78 subjects, all with a DNA mismatch repair gene mutation, by CTC and colonoscopy. We detected altogether 37 polyps or tumors in 28 subjects (prevalence 35.9%), adenomas in 13 subjects (16.7%), CRC in two (2.6%), and hyperplastic polyps in 13 (16.7%). A great majority of the polyps were diminutive. The per-patient sensitivity for detecting all lesions with CTC was 0.25 and 0.29 by two radiologists and the specificities 0.82 and 0.76. For lesions of 10 mm or larger the sensitivities were 0.6 and 1.0 and the specificities 0.96 by each examiner. Each diagnosed the two cancers correctly. We concluded that CTC has an acceptable accuracy for large lesions in the colon but the detection rate for small polyps is not comparable to that in colonoscopy. Therefore CTC remains a second choice in surveillance for use when colonoscopy for some reason is incomplete or unsuitable.     

Volumetric visualization of head and neck CT data for treatment planning.

PURPOSE: To demonstrate the utility of volume rendering, an alternative visualization technique to surface rendering, in the practice of CT based radiotherapy planning for the head and neck. METHODS AND MATERIALS: Rendo-avs, a volume visualization tool developed at the University of Chicago, was used to volume render head and neck CT scans from two cases. Rendo-avs is a volume rendering tool operating within the graphical user interface environment of AVS (Application Visualization System). Users adjust the opacity of various tissues by defining the opacity transfer function (OTF), a function which preclassifies voxels by opacity prior to rendering. By defining the opacity map (OTF), the user selectively enhances and suppresses structures of various intensity. Additional graphics tools are available within the AVS network, allowing for the manipulation of perspective, field of view, data orientation. Users may draw directly on volume rendered images, create a partial surface, and thereby correlate objects in the 3D scene to points on original axial slices. Information in volume rendered images is mapped into the original CT slices via a Z buffer, which contains the depth information (Z coordinate) for each pixel in the rendered view. Locally developed software was used to project conventionally designed GTV contours onto volume rendered images. RESULTS: The lymph nodes, salivary glands, vessels, and airway are visualized in detail without prior manual segmentation. Volume rendering can be used to explore the finer anatomic structures that appear on consecutive axial slices as "points." Rendo-avs allowed for acceptable interactivity, with a processing time of approximately 5 seconds per 256 x 256 pixel output image. CONCLUSIONS: Volume rendering is a useful alternative to surface rendering, offering high-quality visualization, 3D anatomic delineation, and time savings to the user, due to the elimination of manual segmentation as a preprocessing step. Volume rendered images can be merged with conventional treatment planning images to add anatomic information to the treatment planning process.     

A follow-up study of physical activity and incidence of colorectal polyps in African-American women.

BACKGROUND: Physical activity is associated with a reduced risk of colon cancer, but the effect of activity on colorectal adenomas, which are precursors to colon cancer, is uncertain. The influence of physical activity on colorectal adenomas among African-American women is of particular interest because African-American women have an increased risk of colon cancer relative to other U.S. women. METHODS: We prospectively assessed the relation of physical activity to the incidence of colorectal polyps among African-American women. We followed 45,400 women in the Black Women's Health Study from 1997 to 2003. Data were obtained by biennial mailed questionnaires. During 287,029 person-years of follow-up, 1,390 women reported having been diagnosed with colorectal polyps. A review of medical records of 58 women who reported colorectal polyps indicated that 59% had adenomas and 41% had hyperplastic polyps. We converted hours per week of vigorous exercise and hours per week of walking to metabolic equivalent (MET)-hours. We estimated incidence rate ratios with Cox proportional hazard models, controlling for age, body mass index, smoking, family history of colorectal cancer, and education. RESULTS: For total MET-hours/wk spent in walking and vigorous exercise, the incidence rate ratio decreased from 0.94 for <5 MET-hours/wk to 0.72 for >or=40 MET-hours/wk (P(trend) = 0.01). The inverse association was apparent among most subgroups examined, including women who may be at higher risk of colorectal adenomas because of being obese. CONCLUSIONS: Increased physical activity is associated with a reduced incidence of colorectal polyps among African-American women.     

Quantitative analysis of colorectal mucosal lesions by autofluorescence endoscopy: discrimination of carcinomas from other lesions

A newly developed auto?uorescence (AF) imaging technique was applied during colonoscopy in a clinical setting. This pilot study was conducted to evaluate the clinical feasibility of applying AF endoscopy for distinguishing colorectal lesions. A total of 54 colorectal mucosal lesions obtained from 43 patients who underwent both white-light and AF endoscopy and were treated by endoscopy or surgery were assessed. Of the lesions, 11 were hyperplastic polyps, 30 were adenomas and 13 were carcinomas. To quantify the AF intensity, a color-contrast index (CCI) was determined and evaluated in relation to the histology, size and shape of each lesion. CCI was significantly associated with the histology and size of the lesions, but not their shape. CCI increased as the malignant potential increased (in the order of hyperplastic polyps→adenomas→carcinomas), irrespective of the lesion size (r=0.797, p<0.0001 for size>8 mm; r=0.622, p=0.0045 for size>8 mm but >15 mm; r=0.644, p=0.0071 for size>15 mm). In each size group, CCI tended to be higher for carcinomas than for adenomas, and also higher for adenomas than for hyperplastic polyps. CCI allowed discrimination of adenomas/carcinomas from hyperplastic polyps with 95.3% sensitivity and 63.6% specificity (cut-off value, 14.5), and of colorectal carcinomas from adenomas with 84.6% sensitivity and 80.0% specificity (cut-off value, 28.0). These results suggest that the quantitative analysis of AF intensity using CCI is helpful to discriminate among different types of colorectal mucosal lesions, including carcinomas.     

Colorectal adenomas: clinical and morphological aspects. A review of 166 polyps from 124 Dutch patients

In a series of 124 consecutive Dutch patients the clinical and morphological features of 166 endoscopically removed colorectal adenomatous polyps were reviewed. The most frequent clinical symptom was manifest blood loss with the stools (51%), but no specific adenoma symptom seemed to exist. Barium enema X-ray examination was done in 108 patients, whereas all patients were colonoscoped. The routinely performed barium examinations detected 71% of the polyps that were found during endoscopy, but not all X-ray examinations were air contrast barium enemas. A good correlation between the localization of the adenomas after both diagnostic modalities was found, indicating that more than 80% were located in the left part of the colon. Nineteen percent of the patients had had a metachronous (pre)neoplastic lesion removed from their large bowel previously, while 40% of the patients had a synchronous polypoid lesion at the moment of polypectomy. Sixty-two percent of the adenomas were tubular, whereas 38% were villous adenomas. There was a strong correlation between size and villous architecture (r = 0.38; p less than 0.001). The epithelial dysplasia was mild in 21%, moderate in 70% and severe in 9% of the adenomas. The degree of dysplasia correlated well with the villous type of mucosal growth (r = 0.24; p less than 0.005). These findings indicate that, 1) there are no colorectal adenoma specific symptoms, 2) to detect colorectal adenomas colonoscopy is the investigation of choice, 3) after the detection of a colorectal adenoma the whole colon should be investigated, 4) colorectal adenoma patients should be kept under surveillance, and 5) determination of the diameter and of the degree of epithelial cell dysplasia may be helpful in assessing the biological behavior of an adenomatous polyp.     

Place du coloscanner et de la coloscopie chez le sujet âgé

CT colonography, also called virtual colonoscopy, is a new imaging technique used to examine the entire colon. The results produced by such a technique depend on the quality of the bowel preparation, the inflation procedure and the types of post-processing techniques available. In frail elderly patients, localizing polyps may no longer be the issue, but rather the diagnosis of an already established cancer in order to define the best therapeutic approach. In such cases, water enema multi-row computed tomography, with or without bowel preparation, could be performed. This technique has demonstrated potential for the preoperative localization of colorectal cancer (with a reported 95% sensitivity for colorectal tumours superior to 1 cm and effectiveness in the detection of metastases). We will present the technical characteristics, clinical results, pitfalls, limitations and potential uses of these new CT techniques, which may represent major progress in the screening and diagnosis of colon cancer in elderly patients.     

Colorectal serrated adenocarcinoma shows a different profile of oncogene mutations, MSI status and DNA repair protein expression compared to conventional and sporadic MSI-H carcinomas

Molecular characterization has been extensively studied in serrated polyps but very little is known in serrated adenocarcinomas (SACs). We analyzed the incidence of KRAS, BRAF and PIK3CA mutations, microsatellite instability (MSI) status and loss of the DNA repair proteins MLH1, MSH2, MSH6 and MGMT in a series of 89 SAC, 81 matched conventional carcinomas (CC) and 13 sporadic colorectal cancer showing histological and molecular features of high-level MSI (sMSI-H). Our results demonstrate that KRAS are more prevalent than BRAF mutations in SAC (42.7% vs. 25.8%; p = 0.011) being the KRAS-mutated cases even more abundant in SAC displaying adjacent serrated adenomas (51%). G12D and E545K are the most common KRAS and PIK3CA mutations found in SAC, respectively. SAC show higher frequency of MGMT loss compared to CC (50.6% vs. 25.3%; p = 0.001) especially in distal colon/rectum (60.0% vs. 21.6%; p = 0.0009). SAC differ from sMSI-H in terms of KRAS and BRAF mutation prevalence, MSI status and MLH1 expression (p = 0.0003, p < 0.0001, p < 0.0001, p < 0.001, respectively). SACs are more often KRAS-mutated and microsatellite stable and display different molecular and immunohistochemical characteristics compared to CC and sMSI-H.