Colorectal cancer screening

INTRODUCTION Colorectal cancer is a major public health burden. It is the fourth most common form of cancer worldwide and the most frequent in North America, Australia, New Zealand, Argentina, and parts of Europe[1]. When colorectal can- cer is detected a…     

Colorectal cancer screening:20 years of development and recent progress

Colorectal cancer(CRC)is the second most common cancer in Europe and its incidence is steadily increasing.This trend could be reversed through timely secondary prevention(screening).In the last twenty years,CRC screening programs across Europe have experienced considerable improvements(fecal occult blood testing;transition from opportunistic to population based program settings).The Czech Republic is a typical example of a country with a long history of nationwide CRC screening programs in the face of very high CRC incidence and mortality rates.Each year,approximately 8000 people are diagnosed with CRC and some 4000 die from this malignancy.Twenty years ago,the first pilot studies on CRC screening led to the introduction of the opportunistic Czech National Colorectal Cancer Screening Program in 2000.Originally,this program was based on the guaiac fecal occult blood test(FOBT)offered by general practitioners,followed by colonoscopy in cases of FOBT positivity.The program has continuously evolved,namely with the implementation of immunochemical FOBTs and screening colonoscopy,as well as the involvement of gynecologists.Since the establishment of the Czech CRC Screening Registry in 2006,2405850 FOBTs have been performed and 104565 preventive colonoscopies recorded within the screening program.The overall program expanded to cover 25.0%of the target population by 2011.However,stagnation in the annual number of performed FOBTs lately has led to switching to the option of a population-based program with personal invitation,which is currently being prepared.     

Colorectal cancer screening in Europe

Colorectal cancer (CRC) is the second most freq uent malignant disease in Europe. Every year, 412 000 people are diagnosed with this condition, and 207 000 patients die of it. In 2003, recommendations for screening programs were issued by the Council of the European Union (EU), and these currently serve as the basis for the preparation of European guidelines for CRC screening. The manner in which CRC screening is carried out varies significantly from country to country within the EU, both in terms of organization and the screening test chosen. A screening program of one sort or another has been implemented in 19 of 27 EU countries. The most frequently applied method is test - ing stool for occult bleeding (fecal occult blood test, FOBT). In recent years, a screening colonoscopy has been introduced, either as the only method (Poland) or the method of choice (Germany, Czech Republic).     

大肠癌临床表现的多样性及其误诊

本文报道1970年1月至1995年12月在北京协和医院经手术病理确诊的791例大肠癌,其中结肠癌396例,直肠癌395例,年龄20～85岁,平均54.4岁。分析结果提示:(1)本组大肠癌手术病例逐年增多。(2)Duke A、B期占36％,C、D期平均误诊时间比A、B期长3个月。(3)以粘液血便,便鲜血、腹痛伴包块,首发贫血及间断发烧为临床重要表现,分别占大肠癌的15.3％、10.2％、7.6％、5.4％及2.0％。这些病人一度被误诊为菌痢、内痔、急慢性肠梗阻、贫血或肠结核等。(4)7cm以下的直畅癌占42.2％,其有75.1％的患者却未做肛门指诊,是误诊的重要原因之一。(5)粪潜血试验阳性率为84％,可作为筛查的一种手段。     

结直肠癌筛查及其进展

结直肠癌(CRC)是最常见的恶性肿瘤之一,近年来我国CRC发病率总体呈现上升趋势,在消化系统恶性肿瘤中居第二位。CRC筛查可显著降低其发病率和死亡率,筛查方法多样,目前以免疫化学法粪便隐血试验(FIT)和结肠镜检查为基础的两步法筛查方案为多个国家的权威指南或共识所推荐,其他筛查方法可作为个体化的选择和补充。对于结直肠息肉超过10枚同时有CRC个人史或家族史,或结直肠息肉超过20枚的极高危人群,应行多基因种系突变检测。     

Screening for colorectal cancer in average-risk populations

Screening average-risk populations for colorectal cancer can reduce the incidence and mortality of colorectal cancer. Effectiveness depends on programmatic adherence and quality. This review discusses the evidence supporting the use of currently available screening tests. The discussion specifically focuses on programmatic issues and highlights the importance of quality assurance in each program.     

Screening for Colorectal Cancer in Personnel of an Academic Medical Center

The colorectal cancer (CRC) screening program in Israel offers the average-risk population fecal occult blood tests from the age of 50 years. Compliance, however, is very low, reaching only 6% of eligible persons in 2005. Our aim in this study was to describe the results of an improved CRC screening program directed at the in-house staff of Beilinson Hospital. All employees of Beilinson Hospital over age 50 years were sent a letter explaining the new CRC screening program and an accompanying questionnaire. Responders who reported a family history of CRC or related cancers or symptoms were offered colonoscopy; the remainder were offered sigmoidoscopy or, if they preferred, colonoscopy. Two hundred twenty of the 888 candidates (24.7%) completed the questionnaire, of whom 144 (16.2%) agreed to further investigation. These included 90 of 105 patients with a positive questionnaire and 20 of 115 with a negative questionnaire who underwent colonoscopy and 34 of 115 with a negative questionnaire who underwent sigmoidoscopy. The colonoscopy group included 26 of the 30 patients (86.6%) with a positive family history. Early-stage CRC was diagnosed in three patients (1.36%), all with a positive questionnaire. There were no pathologic findings on sigmoidoscopy. The sensitivity, specificity, and positive and negative predictive values of the questionnaire for identifying subjects with CRC or advanced adenoma were 100.00%, 18.86%, 2.27%, and 100.00%, respectively. In conclusion, using hospital facilities, we initiated a unique CRC screening program for employees. Our method may be applicable in other medical centers for the detection of adenomas and CRCs in the early, curative stages.     

Performance Characteristics and Comparison of Two Fecal Occult Blood Tests in Patients Undergoing Colonoscopy

We investigated the use of a new type of FOBT (EZ-Detect) that uses the blood's pseudo-peroxidase activity as an enzymatic catalyst, in a one-step chromogen-substrate system performed by the patient. Asymptomatic patients ≥50 years old received three Hemoccult II (HO) cards and three EZ-Detect (EZ) packages to be used in three consecutive bowel movements. Sensitivity, specificity, positive predictive value, and negative predictive value for detection of colorectal neoplasia was calculated. The study included 207 patients, with a mean age of 58.9 years. Diagnostic accuracy for detection of adenomas was similar for the EZ and HO tests (66.7% vs. 71.0%; P=0.48), while for advanced adenomas diagnostic accuracy for the EZ and HO tests was 86.0% vs. 94.2% (P=0.01), respectively. Most patients preferred the EZ test (92% vs. 8%). We conclude that the EZ test has a diagnostic profile similar to that of the HO test for identification of adenomas; however, for advanced adenomas the diagnostic accuracy was slightly better for the HO. The EZ test was preferred by most patients, which may increase colorectal cancer screening compliance.     

Interval Cancers in Screening with Fecal Occult Blood Test for Colorectal Cancer

Interval cancers, which are cancers diagnosed in spite of one or more negative screening tests, were studied in a randomized population with Hemoccult-II for colorectal cancer in 61,938 persons between 45 and 74 years old. Three biannual screenings were performed from 1985 to 1991, and 52% of all the cancers detected after doing at least one Hemoccult-II test were interval cancers (81 persons). These were more advanced than cancers diagnosed after a positive Hemoccult-II test, of larger size, less frequently of Dukes stage A, more often invading neighboring organs, and less often resectable for cure. They were located in the rectum more often than cancers diagnosed by screening and cancers in controls. Otherwise, interval cancers did not differ from cancers in controls or cancers in non-responders, and all characteristics suggested that no delay in diagnosis resulted from one or more negative Hemoccult-II tests, compared with controls. However, even if screening with Hemoccult-II demonstrates a reduction in mortality from colorectal cancer, the present high number of interval cancers makes it necessary to look for other methods of screening populations for colorectal cancer.     

Screening for colorectal cancer: implications for UK and European initiatives

Abstract Colorectal cancer (CRC) is the third most common cancer after lung and prostate cancers, and is the second most common cancer in women in the United Kingdom (UK) after breast cancer. The disease is well suited for prevention with screening programs. CRC is invariably fatal when diagnosed at an advanced stage but curable when diagnosed early, since it passes through a detectable asymptomatic stage. Screening tests with varying degrees of sensitivity and specificity are available. Prior to implementation of a nationwide national programme in the UK, trials are underway to identify the most sensitive and specific screening modality, and to address patient acceptability and resource implications. Screening for CRC using faecal occult blood (FOB) tests may be feasible. There is evidence to show that this modality saves lives at a cost similar to the breast screening programme currently underway in the UK. One-off flexible sigmoidoscopy is an alternative to FOB screening, and pilot data suggest that the technique is logistically feasible in the UK; a multicentre randomised trial is currently underway. Total colonoscopy is the gold standard test, but at present no large randomised controlled trials support this strategy. Colonoscopy is expensive and labour-intensive, and training issues need to be addressed. At the present time, tailored screening (in which intensity is adjusted for individual risk) appears reasonable. FOB and flexible sigmoidoscopy are cost effective but vary in sensitivity and specificity. Public education programmes are essential for any screening strategy to be effective.     

大肠癌患者一级亲属的电子肠镜与粪便潜血试验的筛查结果分析

目的研究大肠癌先证患者的一级亲属的电子肠镜和粪便潜血试验（faecal occult blood testing, FOBT）筛查的临床意义。方法前瞻性分析大肠癌先证患者的一级亲属186例的电子肠镜和FOBT的筛查结果。FOBT应用试纸免疫法和氨基比林化学法。结果在186例亲属的肠镜检查中阳性病变检出率高达80．1％，其中癌前病变占41．1％，恶性疾病占23．6％。而FOBT的检出率只有22．3％，明显低于肠镜的检出率（P〈0．001）。大肠息肉、息肉癌变和大肠癌在一级亲属的检出率分别为56．5％、6．5％和17．2％，在对照组分别为25．7％、0．5％和6．5％，两组比较，P均小于0．001。本组小于40岁的患者占阳性病变的20．1％和恶性病变的17．1％。肠镜检查检出Dukes A期大肠癌18例，占56．3％，B期12例，占37．5％，C期2例，占6．3％，D期0例。所有大肠癌患者均可进行根治性手术切除。结论在大肠癌先证患者的一级亲属中进行结肠镜筛查明显优于FOBT，具有较高的检出率，并可预防大肠癌和早期诊断大肠癌和提高根治手术率。     

Systematic review of colorectal cancer screening guidelines for average-risk adults: Summarizing the current global recommendations

AIM To summarize and compare worldwide colorectal cancer(CRC) screening recommendations in order to identify similarities and disparities.METHODS A systematic literature search was performed using MEDLINE, EMBASE, Scopus, CENTRAL and ISI Web of knowledge identifying all average-risk CRC screening guideline publications within the last ten years and/or position statements published in the last 2 years. In addition, a hand-search of the webpages of National Gastroenterology Society websites, the National Guideline Clearinghouse, the BMJ Clinical Evidence website,Google and Google Scholar was performed. RESULTS Fifteen guidelines were identified. Six guidelines were published in North America, four in Europe, four in Asia and one from the World Gastroenterology Organization. The majority of guidelines recommend screening average-risk individuals between ages 50 and 75 using colonoscopy(every 10 years), or flexible sigmoidoscopy(FS, every 5 years) or fecal occult blood test(FOBT, mainly the Fecal Immunochemical Test, annually or biennially). Disparities throughout the different guidelines are found relating to the use of colonoscopy, rank order between test, screening intervals and optimal age ranges for screening. CONCLUSION Average risk individuals between 50 and 75 years should undergo CRC screening. Recommendations for optimal surveillance intervals, preferred tests/test cascade as well as the optimal timing when to start and stop screening differ regionally and should be considered for clinical decision making. Furthermore, local resource availability and patient preferences are important to increase CRC screening uptake, as any screening is better than none.     

Prevalence of Proximal Neoplasms Among Asymptomatic Patients According to Distal Colorectal Findings

Colorectal cancer has been described in association with hyperplastic polyposis. Only half of proximal colon cancers are associated with distal adenomas. To compare the prevalence of proximal and advanced neoplasia between patients with distal hyperplastic polyps only; with distal adenomas with or without hyperplastic polyps; and with no distal polyps, we retrospectively analyzed data of 1,064 adults who underwent colonoscopy. Of these patients, 3% had neoplasia. Proximal neoplasia occurred in 0.8% of 945 patients with no distal polyps, compared to none of 19 with distal hyperplastic polyps (P > 0.05) and 6% with distal adenomas (P > 0.05). Proximal advanced neoplasia occurred in 0.6% patients with no distal polyps, compared with none with distal hyperplastic polyps (P > 0.05) and 6% with distal adenomas (P > 0.05). In conclusion, patients with distal hyperplastic polyps, unlike those with distal adenomas, do not exhibit an increased risk for proximal neoplasia or proximal advanced neoplasia compared to those with no distal polyps.     

Screening for Colorectal Cancer in Average-Risk Chinese Population Using a Mixed Strategy with Sigmoidoscopy and Colonoscopy

Purpose The Chinese population has been shown to have more distal colonic neoplasm and a higher sensitivity of sigmoidoscopic screening strategy for detecting advanced neoplasm compared with Western populations. This study was designed to evaluate the efficacy of the mixed screening strategy with sigmoidoscopy and colonoscopy in the average-risk Chinese population. Methods Consecutive average-risk adults aged ≥50 years who underwent colonoscopy as part of a health checkup were enrolled. Data were analyzed in a hypothetical graded screening strategy using colonoscopy on patients older than a certain cutoff age or those with distal sentinel polyps. The sensitivity in detecting advanced colonic neoplasm and advanced proximal neoplasm as well as the number of colonoscopies reduced were assessed. Results Of the 2,106 persons eligible for analysis, 1,193 (56.6 percent) were males and 913 (43.4 percent) were females. If the cutoff ages were 55, 60, and 65 years, and adenoma detected in the distal colon was the indication for subsequent colonoscopy, the detection rate for 1) advanced colonic neoplasm in the entire colon would be 94, 93.1, and 83.6 percent, respectively, and 2) advanced proximal neoplasm would be 84.8, 82.6, and 58.7 percent, respectively. The number of colonoscopic procedures could be reduced by 28, 48, and 65 percent if the cutoff ages were 55, 60, and 65 years, respectively. Conclusions The mixed screening strategy using a cutoff age at 60 years and distal adenoma as the sentinel lesion is an effective screening program in the average-risk Chinese population.     

新疆沙湾地区大肠癌筛查研究的初步结果

目的探讨粪便隐血试验及结肠镜检查作为大肠癌筛查主要方式的临床价值。方法 2007～2009年对沙湾地区无症状及有下消化道症状自愿体检的患者,先行大便隐血试验阳性者进行结肠镜检查,对检查结果进行分析。结果≥40岁受检者共413例,粪便隐血试验阳性者69例,阳性率16.71%,共24例发现了58枚结肠息肉,包括腺瘤性息肉38枚,炎性息肉8枚,增生性息肉12枚;发现结肠癌13例,直肠癌5例,恶性淋巴瘤1例。〈40岁自愿体检者94例,粪便隐血试验阳性者6例,阳性率6.38%,3例患者发现了4枚结肠息肉,包括腺瘤性息肉1枚,炎性息肉2枚,增生性息肉1枚;发现直肠癌1例。结论对无症状自愿体检患者进行粪便及结肠镜检查能较早发现大肠息肉,对大便隐血试验阳性患者行全结肠镜检查更适合于对基层广大农牧民结直肠癌的筛查。     

Colorectal cancer screening:Opportunities to improve uptake,outcomes,and disparities

Colorectal cancer screening has become a standard of care in industrialized nations for those 50 to 75 years of age,along with selected high-risk populations.While colorectal cancer screening has been shown to reduce both the incidence and mortality of colorectal cancer,it is a complex multi-disciplinary process with a number of important steps that require optimization before tangible improvements in outcomes are possible.For both opportunistic and programmatic colorectal cancer screening,poor participant uptake remains an ongoing concern.Furthermore,current screening modalities(such as the guaiac based fecal occult blood test,fecal immunochemical test and colonoscopy) may be used or performed suboptimally,which can lead to missed neoplastic lesions and unnecessary endoscopic evaluations.The latter poses the risk of adverse events,such as perforation and post-polypectomy bleeding,as well as financial impacts to the healthcare system.Moreover,ongoing disparities in colorectal cancer screening persist among marginalized populations,including specific ethnic minorities(African Americans,Hispanics,Asians,Indigenous groups),immigrants,and those who are economically disenfranchised.Given this context,we aimed to review the current literature on these important areas pertaining to colorectal cancer screening,particularly focusing on the guaiac based fecal occult blood test,the fecal immunochemical test and colonoscopy.     

Viewpoints of the target population regarding barriers and facilitators of colorectal cancer screening in the Czech Republic

BACKGROUND Public awareness of colorectal cancer(CRC) and uptake of CRC screening remain challenges. The viewpoints of the target population(asymptomatic individuals older than 50) regarding CRC screening information sources and the reasons for and against participation in CRC screening are not well known in the Czech Republic. This study aimed to acquire independent opinions from the target population independently on the health system.AIM To investigate the viewpoints of the target population regarding the source of information for and barriers and facilitators of CRC screening.METHODS A survey among relatives(aged 50 and older) of university students was conducted. Participants answered a questionnaire about sources of awareness regarding CRC screening, reasons for and against participation, and suggestions for improvements in CRC screening. The effect of certain variables on participation in CRC screening was analyzed.RESULTS Of 498 participants, 478(96%) respondents had some information about CRC screening and 375(75.3%) had participated in a CRC screening test. General practitioners(GPs)(n = 319, 64.1%) and traditional media(n = 166, 33.3%) were the most common information sources regarding CRC screening. A lack of interest or time and a fear of colonoscopy or positive results were reported as reasons for non-participation. Individuals aged > 60 years [adjusted odds ratio(aOR) = 2.30, 95% confidence interval(CI)(1.42-3.71), P = 0.001], females(aOR =1.95, 95%CI(1.26-3.01) P = 0.003), and relatives of CRC patients(aOR = 4.17,95%CI(1.82-9.58) P = 0.001) were more likely to participate in screening.Information regarding screening provided by physicians-GPs:(aOR = 8.11,95%CI(4.90-13.41), P < 0.001) and other specialists(aOR = 4.19, 95%CI(1.87-9.38),P = 0.001) increased participation in screening. Respondents suggested that providing better explanations regarding screening procedures and equipment for stool capturing could improve CRC screening uptake.CONCLUSION GPs and other specialists play crucial roles in the successful uptake of CRC screening. Reduction of the fear of colonoscopy and simple equipment for stool sampling might assist in improving the uptake of CRC screening.