Predictive value of rectal bleeding in screening for rectal and sigmoid polyps.

Overt rectal bleeding is a common symptom of colorectal cancer and polyps but also occurs in apparently healthy people. It is not known how often this represents bleeding from an undiagnosed rectal or sigmoid polyp or cancer. Three hundred and nineteen apparently healthy men aged over 50, selected by random sampling, were interviewed and underwent flexible sigmoidoscopy to at least 30 cm. Polyps of 10 mm or more in diameter were diagnosed in 12, one of whom also had an adenocarcinoma. Rectal bleeding during the previous six months was reported by 48, four of whom were found to have polyps; seven polyps and one cancer were diagnosed among the 271 who reported no rectal bleeding. Rectal bleeding had a specificity of 86%, a sensitivity of 33%, and a positive predictive value of 8% for rectal or sigmoid polyps or cancer. Restricting the analysis to those subjects who regularly inspected their stools did not improve the predictive value. Sigmoidoscopy in apparently healthy subjects with rectal bleeding will not result in the diagnosis of appreciable numbers of rectal and sigmoid polyps or cancers.     

Training Primary Care Physicians in Flexible Sigmoidoscopy—Performance Evaluation of 17, 167 Procedures

The flexible fiber-optic sigmoidoscope is rapidly replacing the rigid sigmoidoscope in routine screening for colorectal cancer. This study was undertaken to evaluate the safety, usage pattern, and efficacy of fiber-optic sigmoidoscopy by evaluating the outcome of training and the results of procedures carried out by a group of primary care physicians. Of 1,153 participants in one-day flexible sigmoidoscopy workshops, 764 (66%) returned questionnaires evaluating their experiences following this training. Of these, 438 physicians had obtained a flexible sigmoidoscope, used it frequently, and had done a total of 17,167 examinations. The average time of scope usage was nine months. Although additional supervised training was suggested at the time of the workshop, 68% of physicians began doing flexible sigmoidoscopy without it. A total of 465 polyps and 153 cancers were detected by the study group for an overall detection rate of 2.7% for polyps and 0.9% for cancers. Four complications were reported. This study indicates that the technique of flexible sigmoidoscopy is readily learned, is diagnostically productive, and is reasonably safe in the hands of primary care physicians.     

Screening for colorectal cancer.

In the United Kingdom there are almost 31,000 new cases of colorectal cancer each year and nearly 20,000 deaths. It is the second most common cause of all deaths from cancer in the United Kingdom. The efficacy of screening with faecal occult blood tests to detect and treat tumours at an early stage, and thereby to reduce mortality, is currently being assessed in several randomised controlled trials. In general, faecal occult blood tests have a low sensitivity and only moderate levels of uptake among the population invited for screening. Until the studies in Denmark, Sweden, and Nottingham report their findings, there is no case for providing such screening routinely to an asymptomatic population. Detecting and removing premalignant adenomas by flexible sigmoidoscopy could be more effective than detecting early localised, asymptomatic cancers in reducing deaths from colorectal cancer. It is estimated that screening people at about the age of 60 by a single flexible sigmoidoscopy examination with appropriate colonoscopic surveillance could prevent 5500 cases of colorectal cancer and 3500 deaths in the United Kingdom each year. A randomised controlled trial to confirm these observations should be seen as a priority.     

The flexible sigmoidoscope as a potential vector of infectious disease, including suggestions for decontamination of the flexible sigmoidoscope

The flexible fiberoptic sigmoidoscope has gained widespread acceptance as a diagnostic tool in the detection and diagnosis of colorectal disease. Since its introduction nearly a decade ago, studies have thus far indicated that in the hands of experienced physicians, flexible sigmoidoscopy is a safe procedure affording greater patient comfort, greater depth of insertion, and a higher yield of neoplastic lesions than rigid sigmoidoscopy, with surprisingly few associated risks. Although reported infrequently, infection is an acknowledged risk of flexible sigmoidoscopy and other endoscopic procedures. The most efficient means of preventing endoscopy-associated infection is uncompromising aseptic practice. Clinical and experimental data obtained from studies designed to investigate endoscopic transmission of infectious organisms and from our own and others' experiences are reviewed. Guidelines for achieving high-level disinfection of the flexible fiberoptic sigmoidoscope are included.     

An evaluation of flexible fibreoptic sigmoidoscopy.

Results of 350 flexible fibreoptic sigmoidoscopy examinations showed a diagnostic yield of 30% compared with 6.5% by rigid sigmoidoscopy of the same patients. The mean time for the examinations was eight minutes, a distance of over 50 cm being visualised in 65% of the patients. Preparation of the bowel with a single phosphate enema was adequate in 95% of the patients. As an outpatient investigation for clinicians fibreoptic sigmoidoscopy is a safe, quick, and useful addition to rigid sigmoidoscopy and should result in a decrease in the number of barium enema examinations required.     

结肠息肉镜下特征、病理分型及癌变规律分析

目的:探讨结肠息肉镜下特征、病理类型及血清学特点与癌变的相关性。方法:收集我院2011年6月~2013年6月肠镜证实的640名结肠息肉患者资料。对年龄、性别、息肉特征(部位、大小、数量、分型、病理等)分析,并将息肉者癌胚抗原与健康人比较。结果:检出息肉1144枚;年龄在41岁~60岁的占52.9%;发生在乙状结肠和直肠的占47.3%;多发及多部位息肉比例为56.9%和46.9%;腺瘤样息肉占87%;随年龄、息肉体积增加,癌变率增加;无蒂息肉癌变率高于有蒂息肉;两组血清癌胚抗原值差异有统计学意义。结论:结肠息肉多发生在乙状结肠和直肠;以腺瘤息肉为主;癌变与年龄、腺瘤大小、形态、病理类型有关。癌胚抗原可能在腺瘤样息肉的筛查及监测癌变存在意义。     

Is Surveillance Colonoscopy Necessary for Patients with Sporadic Gastric Hyperplastic Polyps?

Background

Gastric polyps, such as adenomas and hyperplastic polyps, can be found in various colonic polyposis syndromes. Unlike in sporadic gastric adenomas, in which the increased risk of colorectal neoplasia has been well characterized, information in sporadic gastric hyperplastic polyps was limited.

Aim

To evaluate the association of sporadic gastric hyperplastic polyps with synchronous colorectal neoplasia in a large cohort.

Methods

Patients with sporadic gastric hyperplastic polyps who underwent colonoscopy simultaneously or within six months were consecutively enrolled. Each patient was compared with two randomly selected age and sex matched controls without gastric polyps who also underwent colonoscopy in the same period. Data of patients’ demographics and characteristics of the gastrointestinal polyps were documented.

Results

A total of 261 cases in 118,576 patients who underwent esophagogastroduodenoscopy were diagnosed as sporadic gastric hyperplastic polyps, and 192 of 261 (73.6%) patients underwent colonoscopy. Colorectal neoplasias were identified in 46 (24.0%) of 192 cases and in 40 (10.4%) of 384 controls (P＜0.001). The mean size and distribution of colorectal neoplasias were not significantly different between the two groups. There was a significantly higher rate of colorectal adenoma (odds ratio [OR] 3.2, 95% confidence interval [CI] 1.9–5.3) in the gastric hyperplastic polyps group than in the control group, while the prevalence of colorectal cancer was similar in the two groups. Logistic regression analysis also suggested that the presence of gastric hyperplastic polyps (OR 2.5, 95% CI 1.5–4.0) was an independent risk factor for colorectal neoplasias.

Conclusion

The risk of colorectal adenoma increases in patients with sporadic gastric hyperplastic polyps, and surveillance colonoscopy for these patients should be considered.     

大肠息肉的危险因素分析

目的：探讨大肠息肉在人群中的年龄、性别、病理类型的分布,并探讨体质量指数、吸烟饮酒、血脂水平、相关疾病、饮食习惯及运动状况对大肠息肉发生的影响。方法：选择2011年4月至2013年4月在海军总医院进行电子结肠镜检查的542例患者,将结肠镜检查发现大肠息肉并住院治疗的患者纳入息肉组,将内镜检查无明显异常的患者纳入对照组。比较两组患者的体质量指数、吸烟饮酒、血脂水平、相关疾病、饮食习惯及运动状况等。结果：大肠息肉人群中男性多于女性,40岁以上高发,超重及肥胖者达55．56％;经常饮酒、较少进食蔬菜、水果、粗纤维食物、运动量少及患有高脂血症、高血压、糖尿病、脂肪肝、胆系疾病者易发大肠息肉。结论：高体质量指数、吸烟、高血脂水平、相关疾病、不良饮食习惯、运动量小是大肠息肉发生的危险因素。     

大肠息肉的危险因素分析

目的:探讨大肠息肉在人群中的年龄、性别、病理类型的分布,并探讨体质量指数、吸烟饮酒、血脂水平、相关疾病、饮食习惯及运动状况对大肠息肉发生的影响。方法:选择2011年4月至2013年4月在海军总医院进行电子结肠镜检查的542例患者,将结肠镜检查发现大肠息肉并住院治疗的患者纳入息肉组,将内镜检查无明显异常的患者纳入对照组。比较两组患者的体质量指数、吸烟饮酒、血脂水平、相关疾病、饮食习惯及运动状况等。结果:大肠息肉人群中男性多于女性,40岁以上高发,超重及肥胖者达55.56%;经常饮酒、较少进食蔬菜、水果、粗纤维食物、运动量少及患有高脂血症、高血压、糖尿病、脂肪肝、胆系疾病者易发大肠息肉。结论:高体质量指数、吸烟、高血脂水平、相关疾病、不良饮食习惯、运动量小是大肠息肉发生的危险因素。     

不同年龄大肠息肉患者的临床病理特征分析

目的:探讨不同年龄段大肠息肉的临床及病理特点。方法:选取经电子结肠镜检查确诊大肠息肉并行内镜下息肉切除的患者182例,根据年龄分组,老年组(年龄≥60岁)98例,检出息肉121枚,中青年组(年龄60岁)84例,检出息肉97枚。将老年组和中青年组的性别构成、息肉数量、部位、形态、病理类型及CEA值进行回顾性分析。结果:中青年组男性大肠息肉发生率高于老年组,差异具有统计学意义(P0.01);老年组远端结肠息肉发生率高于中青年组,差异显著(P0.05);中青年组直径在0.5-1.0 cm的息肉枚数明显高于老年组,而老年组山田I型息肉枚数明显高于中青年组,具有统计学意义(P0.05);两组患者腺瘤性息肉的发生率明显高于其他类型息肉,尤其以管状腺瘤为高发;两组间CEA值均部分升高,但无统计学差异(P0.05)。结论:应根据不同年龄组大肠息肉的临床和病理特点,采取相应诊疗方案。     

Flexible sigmoidoscopy in outpatients with suspected colonic disease.

One hundred and fifteen patients attending a gastroenterology clinic were investigated by flexible sigmoidoscopy as outpatients. There were asked to fast before the examination and give a high-volume enema and sedated before the examination. A standard long colonoscope was used rather than the 60-cm sigmoidoscope, which limits the distance that can be examined and forces the operator to work very close to the patient. Preparation was considered good in 95 patients and 49 were examined as far as the hepatic flexure or beyond. Sixty-one patients were found to have lesions of the colon, 25 of them ulcerative colitis, 16 a poly, and nine carcinoma. Despite the fact that these patients were selected (some of them had already had ulcerative colitis diagnosed), flexible sigmoidoscopy proved to be a valuable initial outpatient investigation. The proximal colon was well visualised in 46 patients and a subsequent barium enema was considered unnecessary. There were no complications and the procedure seemed to be well tolerated.     

Benign epithelial gastric polyps--frequency,location, and age and sex distribution

Prospective investigation has been undertaken with the aim to study the frequency, location and age and sex distribution of various histological types of benign gastric epithelial polyps. Histological type--adenomatous, hyperplastic and fundic gland polyps--was diagnosed on the basis of at least three histological samples taken from the polyp. Biopsy samples were also taken from the antrum and the body of the stomach so that gastritis could be graded and classified, and the presence of H. pylori could be determined by histology. All 6,700 patients, who had undergone upper gastrointestinal endoscopy in a one-year period, participated in this study. Among them 42 benign gastric epithelial polyp were found in 31 patients: adenomatous gastric polyps in 7 patients, hyperplastic gastric polyp in 21 and fundic gland polyp in 3 patients. All patients with hyperplastic polyps had chronic active superficial gastritis, whereas most of the patients with adenomatous polyps had a chronic atrophic gastritis with high prevalence of intestinal metaplasia. Among 21 patients with hyperplastic gastric polyps, 16 (76%) patients were positive for H. pylori infection in contrast to only 2 patients (29%) with adenomatous gastric polyps and 1 patient (33%) with fundic gland polyp. Presented data indicates that hyperplastic gastric polyps are the most common and they are associated with the presence of chronic active superficial gastritis and concomitant H. pylori infection. Adenomatous polyps are rarer and they tend to be associated with chronic atrophic gastritis and intestinal metaplasia. Fundic gland polyp is the rarest type of gastric polyps.     

Expression of Parkin,APC, APE1, and Bcl-xL in Colorectal Polyps

Colorectal cancer can develop through molecular, chromosomal, and epigenetic cumulative changes that transform the normal intestinal epithelium into the colorectal polyps, called conventional adenomas (CAs) or serrated polyps (SPs), recognized as precursors of invasive colorectal neoplasia. These benign lesions need to explore the morphology, histological diagnosis, and biomarkers profile to accurately characterize lesions with potential for evolution to cancer. This study aimed to correlate the immunohistochemical expression of Parkin and Adenomatous Polyposis Coli (APC; tumor suppressors), Human Apurinic/Apyrimidinic endonuclease 1 (APE1), and B-cell lymphoma-extra-large (Bcl-xL; oncogenic proteins) in sporadic colorectal polyps with clinical, endoscopic, and diagnostic data. Immunohistochemical analysis was performed on tissue microarray samples of 306 polyps. Based on the Allred score, the expressions were graduated in the cytoplasm and nucleus of superficial and cryptic cells. There was higher Parkin nuclear expression (p=0.006 and 0.010) and APC cytoplasmic expression in cryptic cells (p<0.001) in SPs. CAs, APE1 (p<0.001) and Bcl-xL (p<0.001) were more expressed in the nuclei and cytoplasms, respectively. These results are related to the biological role proposed for these proteins in cellular functions. They can contribute to the diagnosis criteria for polyps and improve the knowledge of biomarkers that could predict cancer development:     

Risk of Advanced Neoplasia in First-Degree Relatives with Colorectal Cancer: A Large Multicenter Cross-Sectional Study

BackgroundFirst-degree relatives (FDR) of patients with colorectal cancer have a higher risk of developing colorectal cancer than the general population. For this reason, screening guidelines recommend colonoscopy every 5 or 10 y, starting at the age of 40, depending on whether colorectal cancer in the index-case is diagnosed at <60 or ≥60 y, respectively. However, studies on the risk of neoplastic lesions are inconclusive. The aim of this study was to determine the risk of advanced neoplasia (three or more non-advanced adenomas, advanced adenoma, or invasive cancer) in FDR of patients with colorectal cancer compared to average-risk individuals (i.e., asymptomatic adults 50 to 69 y of age with no family history of colorectal cancer).ConclusionsIndividuals having two FDR with colorectal cancer showed an increased risk of advanced neoplasia compared to those with average-risk for colorectal cancer. Men had over 2-fold higher risk of advanced neoplasia than women, independent of family history. These data suggest that screening colonoscopy guidelines should be revised in the familial-risk population.     

Age-related model for estimating the symptomatic and asymptomatic transmissibility of COVID-19 patients

Estimation of age-dependent transmissibility of COVID-19 patients is critical for effective policymaking. Although the transmissibility of symptomatic cases has been extensively studied, asymptomatic infection is understudied due to limited data. Using a dataset with reliably distinguished symptomatic and asymptomatic statuses of COVID-19 cases, we propose an ordinary differential equation model that considers age-dependent transmissibility in transmission dynamics. Under a Bayesian framework, multi-source information is synthesized in our model for identifying transmissibility. A shrinkage prior among age groups is also adopted to improve the estimation behavior of transmissibility from age-structured data. The added values of accounting for age-dependent transmissibility are further evaluated through simulation studies. In real-data analysis, we compare our approach with two basic models using the deviance information criterion (DIC) and its extension. We find that the proposed model is more flexible for our epidemic data. Our results also suggest that the transmissibility of asymptomatic infections is significantly lower (on average, 76.45% with a credible interval (27.38%, 88.65%)) than that of symptomatic cases. In both symptomatic and asymptomatic patients, the transmissibility mainly increases with age. Patients older than 30 years are more likely to develop symptoms with higher transmissibility. We also find that the transmission burden of asymptomatic cases is lower than that of symptomatic patients.     

Mutation analysis of <Emphasis Type="Italic">K-ras</Emphasis> protooncogene in colorectal adenocarcinomas and polyps in Russian patients

To estimate diagnostic value of K-ras mutations during cancer risk group formation, they were studied in the samples of sporadic carcinomas (n = 58), benign (n = 33), and malignant (n = 13) polyps of large intestine obtained during surgery or polypectomy. Using PCR analysis, restriction analysis, SSCP analysis and automated sequencing, eight various point mutations were revealed. Six of them were located in codon 12 and two, in codon 13 of the K-ras gene. Mutation frequency in carcinomas, benign and malignant polyps was 43, 49, and 69%, respectively. In the normal tissue samples of colorectum, no changes in codons 12 and 13 in the K-ras gene were observed. Mutations in the groups of Russian patients examined partially overlapped. In patients with colorectal carcinoma the mutation frequency in the K-ras gene was not associated with disease onset age, location, and the extent of tumor differentiation while it was associated with the stage of tumor process. In polyps, the maximum mutation frequency was revealed among patients over 70 years of age as well as in the adenomas of villous histology and large size (≥1cm). No correlation between the K-ras mutation frequency and the extent of polyp dysplasia was observed.     

Germline susceptibility to colorectal cancer due to base-excision repair gene defects

DNA repair is a key process in the maintenance of genome integrity. Here, we present a large, systematically collected population-based association study (2,239 cases; 1,845 controls) that explores the contribution to colorectal cancer incidence of inherited defects in base-excision repair (BER) genes. We show that biallelic MUTYH defects impart a 93-fold (95% CI 42-213) excess risk of colorectal cancer, which accounts for 0.8% of cases aged <55 years and 0.54% of the entire cohort. Penetrance for homozygous carriers was almost complete by age 60 years. Significantly more biallelic carriers had coexisting adenomatous polyps. However, notably, 36% of biallelic carriers had no polyps. Three patients with heterozygous MUTYH defects carried monoallelic mutations in other BER genes (OGG1 and MTH1). Recessive inheritance accounted for the elevated risk for those aged <55 years. However, there was also a 1.68-fold (95% CI 1.07-2.95) excess risk for heterozygous carriers aged >55 years, with a population attributable risk in this age group of 0.93% (95% CI 0%-2.0%). These data provide the strongest evidence to date for a causative role of BER defects in colorectal cancer etiology and show, to our knowledge for the first time, that heterozygous MUTYH mutations predispose to colorectal cancer later in life. These findings have clinical relevance for BER gene testing for patients with colorectal cancer and for genetic counseling of their relatives.     

Linkage of a variant or attenuated form of adenomatous polyposis coli to the adenomatous polyposis coli (APC) locus.

Adenomatous polyps are an intermediate in the pathway to colon carcinoma. An inherited disorder, familial adenomatous polyposis coli (APC), is characterized by hundreds to thousands of adenomatous polyps. A previously reported family had colon cancer associated with a low average but highly heterogenous number of colonic polyps, this phenotype mapped to the APC locus on 5q. Four new families have been ascertained in which the phenotypic pattern was different from classical polyposis but similar to that of the "prototype" kindred reported earlier. By multilocus linkage analysis, the gene responsible for the disease phenotype was mapped, with a high level of confidence, to the APC locus in two of the four families with the attenuated or variant form of polyposis (AAPC); the results for the two remaining kindreds were inconclusive. A combined maximum LOD score of approximately 7.6 at a recombination fraction of 0 was obtained when the results were summed over the four pedigrees with markers closest to the APC locus. The establishment of genetic linkage in such families may point to the APC locus as having a more significant role in inherited predispositions to colorectal cancer than was previously thought.     

Iron concentrations in intestinal cancer tissue and in colon and rectum polyps

A prospective randomized trial was used to determine iron concentrations in intestinal cancer tissue and colorectum polyps. We investigated the possible difference between the concentrations of iron, ferritin, albumin, and hemoglobin in the serum of patients with colorectal cancer and polyps. We also determined the relationship between the iron and ferritin levels in cancer tissue, the localization of neoplasms, and the stage of their development. The study comprises 67 patients with colorectum cancer and 42 patients with colon and rectum polyps. The metal was determined by using the total-reflection X-ray fluorescence (TRXRF) method. The mean concentration of iron in colorectal cancer equaled 46.1 μg/g of the tissue and was higher than in the case of polyps (43.2 μg/g). The mean serum iron level in patients with colorectal cancer was statistically lower than in the serum of patients with polyp and in the control group (54.5, 91.3, and 108.0 μg/g, respectively). The determined average concentration of ferritin in the serum of patients with colorectal cancer equaled 60.4 μg/g and was statistically lower than the level of this enzyme in the serum of patients with polyps (85.2 μg/g) and in the control group (102.0 μg/g). There was no difference between the serum albumin and hemoglobin concentrations in patients with colorectal cancer, polyps, and the control. There was no difference in the levels of iron and ferritin depending on the location of the neoplasm and the stage of its development. Also, there was no difference between the concentrations of iron in the cancer tissue of malignant and benign tumors after taking into consideration sex and age of patients. During the examination we determined significantly higher concentrations of iron in the cancer tissue and not in the polyp. The low levels of iron in the serum of patients with malignant tumor may increase colorectal cancer risk.     

尼龙绳与钛夹在预防内镜下切除大肠宽蒂息肉术后出血的疗效 和安全性的比较

目的:比较尼龙绳和钛夹在预防大肠宽蒂息肉切除后出血的疗效和安全性的比较.方法:从2005年1月至2011年9月连续选择155例患大肠宽蒂息肉和有蒂且顶部直径大于10mm息内的患者.随机分为3组.A组(53例),将尼龙绳套扎息肉的基底部,然后使用常规的套圈器进行息肉电切术.B组(52例),使用常规的套圈器进行息肉电切术,然后残端使用钛夹缝合.C组(50例),使用常规的套圈器进行息肉电切术.结果:所有息肉均成功摘除.A组和B组1例出血;C组5例出血,其中1例需要手术干预.结论:大肠宽蒂息肉常规圈套器进行息肉电切术具有较大的出血风险;尼龙绳和钛夹对内镜下切除大肠宽蒂息肉术后出血具有良好的预防作用.