Strategies for screening for colorectal carcinoma

Four tests commonly used in screening strategies to detect colorectal cancer were examined from a cost-effectiveness perspective. Thirteen combinations of the tests were evaluated. Evaluating a positive fecal occult blood test with a double-contrast barium enema study, followed, if necessary, by colonoscopy, is the most cost-effective strategy for individuals at average risk. An alternative screening strategy for higher-risk individuals or for populations in which the frequency of adenomatous polyps is higher is to follow a positive fecal occult blood test directly with colonoscopy. Sensitivity analysis demonstrated that the superior cost-effectiveness of these two strategies compared with the other 11 modeled strategies is almost independent for reasonable alterations in test cost and for the sensitivities and specificities of the procedures. The major contributing factor to the diagnostic cost is the frequency of adenomatous polyps. The major contributing factor to the marginal cost per year of extended life is the frequency of cancer.     

A decision model and cost-effectiveness analysis of colorectal cancer screening and surveillance guidelines for average-risk adults

OBJECTIVES: Guidelines for colorectal cancer screening and surveillance in people at average risk and at increased risk have recently been published by the American Gastroenterological Association. The guidelines for the population at average risk were evaluated using cost-effectiveness analyses. METHODS: Since colorectal cancers primarily arise from precancerous adenomas, a state transition model of disease progression from adenomatous polyps was developed. Rather than assuming that polyps turn to cancer after a fixed interval (dwell time), such transitions were modeled to occur as an exponential function of the age of the polyps. Screening strategies included periodic fecal occult blood test, flexible sigmoidoscopy, double-contrast barium enema, and colonoscopy. Screening costs in 1994 dollars were estimated using Medicare and private claims data, and clinical parameters were based upon published studies. RESULTS: Cost per life-year saved was $12,636 for flexible sigmoidoscopy every 5 years and $14,394 for annual fecal occult blood testing. The assumption made for polyp dwell time critically affected the attractiveness of alternative screening strategies. CONCLUSIONS: Sigmoidoscopy every 5 years and annual fecal blood testing were the two most cost-effective strategies, but with low compliance, occult blood testing was less cost-effective. Lowering colonoscopy costs greatly improved the cost-effectiveness of colonoscopy every 10 years.     

The workup of the asymptomatic patient with a positive fecal occult blood test

Twenty-two protocols for working up an asymptomatic patient who has a positive fecal occult blood test were evaluated using existing information on the prevalences of cancers, adenomas and other conditions in such patients; the natural history of colorectal cancer; the effectiveness of screening tests; risks; and costs. The authors estimate the impacts of the 22 workup strategies on outcomes such as the chance of finding an existing cancer or adenoma, risks (bleeding and perforation), and financial costs of different strategies involving rigid sigmoidoscopy, flexible sigmoidoscopy, barium enema, and colonoscopy. Two protocols were particularly effective. The first involves performing a barium enema study and following it with colonoscopy; if colonoscopy is negative, the barium enema study should be repeated. The second is to perform colonoscopy and if it is negative, follow it with a barium enema study.     

Acromegaly and intestinal neoplasms.

Acromegalic subjects show increased frequency of neoplastic lesions in the colon and rectum with respect to the general population. Recent prospective studies using colonoscopy have shown a 3 time higher prevalence of intestinal polyps and up to 4 time increased presence of colorectal cancer in acromegaly, independently of sex, age, duration of disease and clinical status of the patients. The polyps are distributed throughout the extension of the large bowel and are often multiple, showing at least two different histologic types: hyperplastic and adenomatous. Sometimes they are associated with intestinal carcinomas. Pancolonoscopy is the procedure of choice for the diagnosis of large bowel neoplasms, even though it may be difficult to complete in these subjects because of the frequent presence of an enlarged and elongated colon. It shows a higher sensitivity and specificity compared to other tests such as the barium enema, fecal occult blood test and serum levels of carcinoembryonic antigen. Therefore, it is recommended to follow up acromegalic patients using pancolonoscopy to obtain early detection of neoplastic lesions in the large bowel.     

A simple score for the identification of patients at high risk of organic diseases of the colon in the family doctor consulting room. The Local IBS Study Group

In order to develop a scoring system for selecting patients at high risk of organic diseases of the colon, who would need a colonoscopy or a barium enema, we conducted a study with 14 GPs in the local health care district of Modena. Over one year, 254 consecutive patients who consulted their GP for chronic abdominal pain were asked to answer a guided questionnaire. A checklist of simple parameters suggestive of the presence of organic diseases of the colon was also registered by the GP. For the final diagnosis, the patients underwent either a colonoscopy or a barium enema. Data collected were analysed by means of a stepwise logistic regression analysis to obtain a weighted score for the diagnosis of either irritable bowel syndrome (score less than 0) or organic disease (score greater than 0). Out of the 25 parameters explored, six were significantly more common among patients with organic disease and weighted as positive score (namely ESR greater than 17 mm, first hour, history of blood in the stool, leukocytosis greater than 10,000 cm3, age greater than 45 years, slight fever and presence of neoplastic colonic diseases in first-degree relatives). On the contrary, five parameters were more frequent among patients with irritable bowel syndrome and weighted as negative score (namely visible distension of the abdomen, feeling of distension, presence of irritable bowel syndrome in first degree relatives, flatulence and irregularities of bowel movement). Our scoring system correctly classified 83.5% of the cases, and it was very sensitive (82.4%) for the diagnosis of organic disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

64排螺旋CT三维成像在结肠疾病诊断中的应用

目的研究64排螺旋CT三维成像的检查方法和临床应用价值。方法通过64排螺旋CT对26例临床高度怀疑结、直肠疾病的患者进行扫描及图像后处理与纤维结肠镜及钡剂灌肠比较,参照手术病理对三维成像进行前瞻性研究。结果本研究26例行64排螺旋CT三维成像检查,其中24例行结肠镜检查、7例行钡灌肠检查、19例行手术病理证实。结论64排螺旋CT三维成像是一项安全,非创伤性和有发展前景的结肠影像检查新技术,将为结肠病变检查开创新的途径。     

就诊的肛肠病人中早期发现大肠癌的研究

本文报道上海市卢湾区建立大肠癌因症就诊早发现网络,在1991年7月至1992年10月期间,对854例有肛肠症状的病人常规开展直肠指检、大便隐血试验、硬管乙结镜检查和/或X线气钡灌肠双对比造影.结果发现大肠癌32例(下称建网后组),检出率3.7%.建网后组的A期率为25%,A+B期率为56.3%,均比建网前组(n=14)的7.1%和21.4 %明显提高.建网后组的手术切除率和根治性切除率分别为84.4%和81.3%,也均比建网前组的57.1%和28.6%明显提高.而建网后组肛肠症状的中位时间则比建网前组明显缩短.作者认为,大肠癌因症就诊早发现网络是提高大肠癌早发现率的一种有效形式,且具有可行性,值得作进一步的探索研究.     

Familial adenomatous polyposis coli--case report

The authors report the case of a young 35 year-old male patient, investigated due to thrombocytosis for three years. First the diagnosis of chronic myeloproliferative disease was made. The diagnosis of familial adenomatous polyposis was only evident in advanced stage of the disease. Upper abdominal US, abdominal CT, double-contrast barium enema examination and colonoscopy proved advanced synchronous colorectal cancers (sigmoid and descending colon) with liver metastases along with polyposis throughout the whole large bowel. Days after the diagnosis was made the patients condition deteriorated rapidly and he died with septic symptoms suggesting bowel perforation and pneumonia. Beside the case report the authors try to give a short overview of the current literature of relatively rare but potentially fatal hereditary colon cancer syndromes to awake the attention of the clinicians to investigate more cautiously the background of unexplained clinical-laboratory signs in young adults.     

Colorectal cancer screening behavior in women attending screening mammography: Longitudinal trends and predictors

PURPOSE: Nationally representative surveys demonstrate that the adherence to screening mammography guidelines are associated with increased prevalence of colorectal cancer (CRC) screening; however, the incidence of CRC screening in the screening mammography population is unknown. Our purpose was to describe non-fecal occult blood test (FOBT) CRC screening utilization by women prior to and subsequent to screening mammography at a large academic medical center. MATERIALS AND METHODS: Using the institutional administrative data base, 17,790 women aged 50 and older who underwent screening mammography between 1998 and 2002 were retrospectively identified. We determined that women were current with non-FOBT CRC screening at the time of mammography if they had undergone flexible sigmoidoscopy or double-contrast barium enema in the 5 years or colonoscopy since 1995, the earliest for which data are available. We excluded FOBT as a form of CRC screening because the administrative data base did not adequately capture episodes of FOBT. Women who were not current were considered eligible for non-FOBT CRC screening. We then assessed the number of women who underwent flexible sigmoidoscopy, barium enema, or colonoscopy within 12 months following mammography. Age, insurance status, Breast Imaging Reporting and Data System classification, recommendations after screening mammography and year of mammography were examined as potential predictors of non-FOBT CRC screening completion. RESULTS: At the time of mammography, 13.3% women were current with non-FOBT CRC screening. Of women eligible for non-FOBT CRC screening at the time of mammography, 1.1% completed non-FOBT CRC screening within 12 months after mammography. The rate of non-FOBT CRC screening completion increased over time. After multivariate analysis, being insured by a commercial managed care organization or by Medicaid remained significant predictors of non-FOBT CRC screening. CONCLUSION: The prevalence of non-FOBT CRC screening is low in the population of women undergoing screening mammography, with an incidence of 1.0%. Future studies should examine whether delivering CRC screening interventions at a screening mammography visit increase adherence to non-FOBT CRC screening.     

The clinical assessment of patients with large bowel symptoms by general practitioners

Objective: To describe the nature and extent of the clinical assessment of patients prior to referral for barium enema examinations within a health district in the UK.

Method: By means of a modified barium enema request form, general practitioners' clinical practices prior to making requests for a barium enema examination were examined over the course of one year. Using a request form with a ‘tear-off’ slip, GPs in Hudders-field, UK, were asked to indicate up to two primary reasons for referral, provide some simple demographic details on patients and to indicate what specific clinical activities had been undertaken prior to ordering a barium enema.

Results: Over the course of the one-year study period, 275 modified x-ray request forms were returned. In relation to the 326 primary reasons given for referral these were subdivided into change in bowel habit (101 [42%]), abdominal pain (55 [23%]), frank or occult rectal bleeding (26 [11%]), weight loss (21 [9%]), iron-deficiency anaemia (6 [3%]), and other (117 [49%]). Patients presenting for barium enema examinations were only likely to have had a rectal examination in 72% of situations, an abdominal examination in 89% and a full blood count in 38%. Proctoscopy was very infrequently performed. In relation to the primary reason for referral, 72% had undergone a rectal examination if they had had a change in bowel habit (90% an abdominal examination). If the patients being referred had experienced abdominal pain, 60% of these would have had a rectal examination and 91% an abdominal examination. No significant effect of age on the tendency to perform rectal or abdominal examinations was noted. Any patient presenting for a barium enema was significantly more likely to have had an abdominal than a rectal examination (odds ratio=3.23 [1.99-5.27]).

Conclusions: This study, taken in context, highlights a need to encourage the adoption of a more rational approach to the assessment of patients within primary care settings. Unfortunately the available evidence to assist general practitioners in the diagnosis of colorectal cancer amongst the types of patients they encounter and in the settings where they work remains unsatisfactory.     

Virtual colonoscopy

Virtual colonoscopy is a fundamentally new imaging technique, in which volumetric CT or MRI data are processed to virtual endoscopic images of the colon. The main application is early detection of colorectal cancer. To date, no data of studies on screening for colorectal cancer are available. The results of clinical studies show comparable results for endoscopy and virtual colonoscopy for the detection of clinically relevant polyps (> or = 1 cm) and better results of virtual colonoscopy than of conventional barium studies. Whether virtual colonoscopy as a minimally invasive technique will gain a place in screening for colorectal cancer depends on several issues such as costs, effectiveness and acceptance by patients.     

Impact of UK Colorectal Cancer Screening Pilot on hospital diagnostic services

OBJECTIVE: To determine the impact of the UK Colorectal Cancer Screening Pilot on hospital services involved in the diagnosis of colorectal cancer (predominantly colonoscopy, double contrast barium enema and pathology). METHODS: Routine data from seven hospitals at two sites within Scotland and England participating in the Pilot were collected on activity levels and waiting times for key hospital services (GI medicine, surgery and radiology), plus questionnaire survey data from hospital consultants. RESULTS: Hospital colonoscopy activity increased by 31 per cent in Scotland and 21 per cent in England due to the investigation of faecal occult blood testing (FOBt) positive subjects. The demand for symptomatic (non-screening) colonoscopy also increased. Pilot-generated activity was less than predicted for barium enema services (maximum 3 per cent increase in service volume) but greater than expected for pathology, with approximately 200 specimens/month generated. Out-patient review of Pilot colonoscopy patients and associated administrative duties added substantially to overall GI service workload, but quantification was limited by the quality of routinely available data. There was a wide discrepancy in colonoscopy waiting times between screened and symptomatic patients, with predominantly longer waits for symptomatic patients: otherwise the quality of colonoscopy services appeared to improve. In any future national screening programme, follow-up of patients with adenomas will result in a further increase of 28 per cent in the number of colonoscopies generated (over and above colonoscopy for FOBt-positive subjects), adding substantially to overall workload. CONCLUSIONS: During the planning of any successful national colorectal cancer screening programme, careful consideration must be given to the wider aspects of workload associated with screening, as well as to the implementation of appropriate hospital data collection systems.     

医源性结肠穿孔32例临床分析

目的 :探索医源性结肠穿孔有效的诊断和治疗方法。方法 :回顾性分析 32例医源性结肠穿孔的临床资料。结果 :全组 32例 ,男性 19例 ,女性 13例。 18例源于结肠镜检查 ,14例源于空气或钡剂灌肠。腹痛 (70 % )为最常见症状 ,肠腔外气体或钡剂 (5 6 % )为最常见的影像学表现。穿孔部位常见于乙状结肠和横结肠。全部病例得到手术治疗。 19例早期 (2 4h)手术 ,13例延迟 (平均 4d)手术。 14例进行单纯修补或切除吻合 ,18例进行结肠造口。 4例 (12 5 % )死亡。延迟手术组或结肠造口组死亡率明显增高。结论 :对于没有明显腹腔污染的医源性结肠穿孔 ,单纯修补或切除吻合是合理的 ,对于多数病例 ,因经过肠道准备 ,应避免结肠造口以减少并发症发生率和死亡率     

Increased use of colorectal cancer tests--United States, 2002 and 2004

Colorectal cancer is the second leading cause of cancer-related death (after lung/bronchus cancer) in the United States. In 2002, a total of 139,534 adults in the United States had colorectal cancer diagnosed, and 56,603 died. The U.S. Preventive Services Task Force and other national organizations recommend that adults aged >/=50 years be screened for colorectal cancer with one or more of the following tests: fecal occult blood testing (FOBT) every year, sigmoidoscopy or double-contrast barium enema every 5 years, or colonoscopy every 10 years. To estimate current rates of use of colorectal cancer screening tests and to evaluate changes in test use, CDC compared data from the 2002 and 2004 Behavioral Risk Factor Surveillance System (BRFSS) surveys. This report describes the results of that comparison, which indicated that the proportion of BRFSS respondents reporting use of FOBT and/or sigmoidoscopy or colonoscopy had increased overall from 2002 to 2004. Measures to increase awareness and encourage regular colorectal cancer screening must be continued to reduce mortality from colorectal cancer.     

Factors Influencing Choices for Colorectal Cancer Screening Among Previously Unscreened African and Caucasian Americans: Findings from a Triangulation Mixed Methods Investigation

We investigated factors that influence choice of colorectal cancer (CRC) screening test and assessed the most- and least-preferred options among fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, and double contrast barium enema among adults with varied race, gender, and geographic region demographics. Mixed methods data collection consisted of 10 focus group interviews and a survey of the 93 focus group participants. Participants were ≥50 years of age and reported not having been screened for colorectal cancer in the last ten years. Analyses examined differences by race, gender, and geographic location. Participants had modest knowledge about CRC and there were fewer correct answers to knowledge questions by African Americans. Participants recognized value of early detection, and identified health symptoms and their doctor’s recommendation as influential for obtaining CRC screening. They chose colonoscopy and FOBT as the most preferred tests, while barium enema was least preferred. The analysis revealed intra-group variations in preference, though there were no significant differences by race, gender, or location. Openness of discussing this sensitive topic, lack of knowledge about colorectal cancer and screening costs, and diversity of preferences expressed within study groups suggest the importance of patient-physician dialogue about colorectal cancer screening options. New approaches to promoting colorectal cancer screening need to explore methods to facilitate patients establishing and expressing preferences among the screening options.     

大肠息肉高频电凝切129例临床分析

目的分析电子结肠镜下高频电凝切除大肠息肉的临床效果。方法对129例238枚电子肠镜检查中检出的大肠息肉患者的临床表现、内镜特点及病理资料以及高频电刀治疗结果进行总结和分析。结果50～69岁大肠息肉发病率较高(82.94%),息肉好发部位为直肠,占34.11%,病理类型以炎性息肉(32.56%)、增生性息肉(31.78%)和腺瘤性息肉(27.13%)常见。除9例腺癌转外科继续治疗外余120例均治愈,未发生严重并发症。结论电子结肠镜下高频电凝切除大肠息肉安全、疗效可靠,是治疗大肠息肉的最佳手段。     

Colonoscopy: a survey of its value in a teaching hospital surgical unit.

A survey has been undertaken of the diagnostic, therapeutic and economic value of colonoscopy in a teaching hospital surgical unit. Provided it is undertaken in conjunction with a good clinical history and double contrast barium enema, colonoscopy provides a high yield of information bearing upon the patient's subsequent management. Therapeutic polypectomy was undertaken in 21% of examinations. Its value in acute colonic disease is discussed, and the importance of training colonoscopists for the future is emphasized.     

低剂量64层螺旋CT成像对结直肠癌的诊断价值

目的：评价低剂量64层螺旋CT扫描（VCT）对结直肠癌的诊断价值,为结直肠CT成像检查提供依据。方法：对40例经临床拟诊为结直肠癌患者行结肠充气低剂量（50mAs）64层VCT,利用工作站后处理软件获得多平面重建（multiplanar reformation,MPR）、三维表面遮盖显示（shaded-surface display。SSD）、透明显示（Raysum）、CT仿真内窥镜图像（CTVC）及结直肠粘膜剖开图像。将低剂量64层VCT诊断结果与结直肠镜或手术病理进行对比。结果：40例中,经手术或结直肠镜活检病理证实结肠癌32例和非结肠癌8例。低剂量VCT正确诊断32例结肠癌病例（包括并发病灶及转移灶）中的30例和8例非结直肠癌中的5例,诊断的敏感度、特异度和准确度分别为：93．75％（30／32）,62．5％（5／8）,87．5％（35／40）。结论：低剂量VCT是安全、无创、快速、全面评价的结直肠癌的方法,可以完全替代钡剂灌肠检查,是结直肠癌筛选、术前分期、预后评估及术后随诊的首选方法。     

Using VA administrative data to measure colorectal cancer screening adherence among average-risk non-elderly veterans

This study represents a new application of Veterans Affairs (VA) administrative data for measuring VA system-wide performance of colorectal cancer (CRC) screening adherence among veterans at average-risk for CRC. Our new measurement has two features: it is specifically designed for average-risk populations and is applied repeatedly at the veteran level each year over the study period. Using 1997–2007 VA administrative data, we developed an algorithm that first constructed 7 independent cohorts of average-risk veterans eligible for CRC screening, one for each year from 2001 to 2007, and then appended the seven cohorts together to form 2001–2007 veteran-level panel data. Veterans in a cohort for a given year were considered adherent if they received fecal occult blood test (FOBT) during that given year, or received flexible sigmoidoscopy (FS), double-contrast barium enema (DCBE), or colonoscopy during that given year or the 4 previous years. The main analysis shows that VA CRC screening rates increased from 30.11% in 2001 to 35.51% in 2004, but declined to 31.54% in 2007. Among the screened, the proportion adherent to colonoscopy increased over the 7-year period while the proportion adherent to FOBT, FS, or DCBE decreased during the same period. Sensitivity analyses, including use of a 10-year retrospective window for determining the screening adherence of colonoscopy, show the robustness of the main analysis. This new algorithm demonstrates that VA administrative data may be used for assessing VA performance of CRC screening adherence of average-risk veterans. Furthermore, our panel data may enhance understanding of factors associated with CRC screening adherence.     

Colorectal polyps in children. A study of 34 patients

AIM: To assess the frequency and the clinical features of polyps of the colon and rectum in children. METHODS: A total of 34 patients (20 boys and 14 girls, mean age: 5.4 years) were enrolled in this 14-years retrospective study. Diagnosis was done for almost all patients by colonoscopy (n=8) or recto-sigmoidoscopy (n= 19). After endoscopic polypectomy, polyp's type is determined by histological examination. RESULTS: Minimal and relapsing rectal bleeding was the most frequent finding of polyps of the colon and rectum (85.3%) followed by spontaneous emission of polyp (n=3), rectal prolapses (n=2), chronic constipation (n=1) and abdominal pain (n=1). The polyp was unique in all cases and with a mean size of 12 mm. The majority of polyps were localized in the rectum or sigmoid (97%) and were pediculate (81.2%). Endoscopic polypectomies concerned 26 polyps while two small polyps were left. Most of the polyps corresponded histologically to juvenile polyps (96.2%). The immediate post-op course was uneventful for 26 children. CONCLUSION: Our study suggests that rectal bleeding is the most frequent finding of polyps of the colon and rectum in childhood. Outcome after endoscopic polypectomy is good.