Can quantification of faecal occult blood predetermine the need for colonoscopy in patients at risk for non‐syndromic familial colorectal cancer?

BACKGROUND: Patients at risk for non-syndromic (Lynch or polyposis) familial colorectal neoplasia undergo colonoscopic surveillance at intervals determined by clinically ascertained protocols. The quantitative immunochemical faecal occult blood test for human haemoglobin is specific and sensitive for significant colorectal neoplasia (cancer or advanced adenomatous polyp). AIM: To determine immunochemical faecal occult blood test efficacy for identifying significant neoplasia in at-risk patients undergoing elective colonoscopy. METHODS: We retrospectively identified consecutive at-risk patients who provided three immunochemical faecal occult blood tests before colonoscopy. Quantitative haemoglobin analysis was performed by the OC-MICRO automated instrument using the 100 ng Hb/mL threshold to determine positivity. RESULTS: In 252 at-risk patients undergoing colonoscopy; five had cancer, 14 an advanced adenoma and 46 a non-advanced adenoma. The immunochemical faecal occult blood test was positive in 31 patients (12.3%). Sensitivity, specificity, positive and negative predictive values for cancer were: 100%, 90%, 16% and 100%, and for all significant neoplasia: 74%, 93%, 45% and 98%. With 88% fewer colonoscopies, all colorectal cancers and 74% of all significant neoplasia would have been identified by this one-time immunochemical faecal occult blood test screening. CONCLUSIONS: A sensitive, non-invasive, interval screening test might be useful to predetermine the need for colonoscopy in this at-risk population and minimize unnecessary examinations. This favourable retrospective evaluation will be extended to a prospective study.     

A sensitive guaiac faecal occult blood test is less useful than an immunochemical test for colorectal cancer screening in a Chinese population

BACKGROUND: Colorectal cancer screening by guaiac faecal occult blood test has been shown to reduce the incidence and mortality of colorectal cancer in Western populations. The optimal faecal occult blood test, whether guaiac or immunochemical, for colorectal cancer screening in the Chinese population remains to be defined. AIM: To compare the performance characteristics of a sensitive guaiac-based faecal occult blood test (Hemoccult SENSA) and an immunochemical faecal occult blood test (FlexSure OBT) in a Chinese population referred for colonoscopy. METHODS: One hundred and thirty-five consecutive patients who were referred for colonoscopy and who met the study inclusion criteria took samples for the two faecal occult blood tests simultaneously from three successive stool specimens, with no dietary restrictions. All tests were developed and interpreted by a single experienced technician who was blind to the clinical diagnosis. The sensitivity, specificity and positive predictive value for the detection of colorectal adenomas and cancers were estimated for the two tests. RESULTS: The sensitivity, specificity and positive predictive value for the detection of significant colorectal neoplasia (adenomas > or = 1.0 cm and cancers) were 91%, 70% and 18% for Hemoccult SENSA and 82%, 94% and 47% for FlexSure OBT. The specificity and positive predictive value were significantly higher for FlexSure OBT than for Hemoccult SENSA (P < 0.001 and P = 0.016, respectively). Combining the positive results from both faecal occult blood tests did not improve the accuracy. CONCLUSION: The positive predictive value of the immunochemical faecal occult blood test for the detection of significant colorectal neoplasia was 29% better than that of the sensitive guaiac-based test. This may relate to the Chinese diet and requires further study. The poor specificity of the sensitive guaiac-based test, without dietary restriction, makes it less useful for colorectal cancer screening in a Chinese population.     

A quantitative immunochemical faecal occult blood test is more efficient for detecting significant colorectal neoplasia than a sensitive guaiac test

BACKGROUND: The sensitive guaiac faecal occult blood test, Haemoccult SENSA (HOS; Beckman Coulter, Fullerton, CA, USA), is our standard screening test for significant colorectal neoplasia. We evaluated an automatically-developed, quantified human haemoglobin immunochemical faecal test, OC-MICRO (Eiken Chemical Co., Tokyo, Japan), to improve test specificity and so reduce the colonoscopy burden. AIM: To compare guaiac faecal occult blood test and immunochemical faecal test diagnostic efficacy and costs for identifying significant neoplasia. METHODS: Colonoscopies were performed on patients who prepared three daily guaiac faecal occult blood tests with or without immunochemical faecal tests. RESULTS: Total colonoscopy was performed on 151 subjects who prepared both guaiac and immunochemical faecal tests (group 1) and the positive predictive values (PPV) were also compared to those of 162 subjects undergoing colonoscopy for positive guaiac faecal occult blood tests (group 2). In group 1, comparative sensitivity, specificity, and PPVs for significant neoplasia with guaiac faecal occult blood test were 75%, 34%, and 12% (PPV, 18% for group 2) and with immunochemical faecal test were 75%, 94% and 60% (P < 0.01 for specificity). The number of colonoscopy examinations needed to detect a significant neoplasm because of positive faecal occult blood tests was six to eight with HOS and two with OC-MICRO at 21-31% the cost of evaluating a positive guaiac faecal occult blood test. CONCLUSION: An immunochemical faecal test maintains the high sensitivity of guaiac faecal occult blood test, but significantly reduces the colonoscopy burden and screening costs.     

Comparative evaluation of a new bedside faecal occult blood test in a prospective multicentre study

BACKGROUND: Faecal occult blood testing is an established method of colorectal neoplasia screening. Guaiac-based tests are limited by poor patient compliance, low sensitivity, specificity and positive predictive value. Newer immunochemical-based tests, accurate but tedious, require a well-established laboratory set up. There is need for simpler immunochemical tests that can be performed at the out-patient clinic. AIM: To compare the performance characteristics of a new bedside immunological test strip device with a sensitive Guaiac-based and established immunochemical test for detection of faecal occult blood in patients undergoing colonoscopy. METHODS: A total of 389 consecutive patients from four centres who were referred for colonoscopy also provided the stool samples for detection of occult blood without dietary restrictions. Stool tests performed were (i) Guaiac-based, (ii) immunochemical enzyme-linked immunosorbent assay and (iii) bedside immunochemical strip test. RESULTS: At the optimal threshold level, the sensitivity and specificity of the beside immunochemical strip test for detection of significant colorectal neoplasia (adenomas >1.0 cm and carcinomas) were 60% and 95%, respectively. CONCLUSIONS: This bedside immunochemical strip test proved to be a simple, convenient, non-cumbersome and accurate tool with similar performance characteristics for detection of any bleeding lesion including colorectal neoplasia when compared with an established immunochemical faecal occult blood test.     

As tests evolve and costs of cancer care rise: reappraising stool-based screening for colorectal neoplasia

Background Colorectal cancer screening and treatment are rapidly evolving. Aims To reappraise stool‐based colorectal cancer screening in light of changing test performance characteristics, lower test cost and increasing colorectal cancer care costs. Methods Using a Markov model, we compared faecal DNA testing every 3 years, annual faecal occult blood testing or immunochemical testing, and colonoscopy every 10 years. Results In the base case, faecal occult blood testing and faecal immunochemical testing gained life‐years/person and cost less than no screening. Faecal DNA testing version 1.1 at $300 (the current PreGen Plus test) gained 5323 life‐years/100 000 persons at $16 900/life‐year gained and faecal DNA testing version 2 (enhanced test) gained 5795 life‐years/100 000 persons at $15 700/life‐year gained vs. no screening. In the base case and most sensitivity analyses, faecal occult blood testing and faecal immunochemical testing were preferred to faecal DNA testing. Faecal DNA testing version 2 cost $100 000/life‐year gained vs. faecal immunochemical testing when per‐cycle adherence with faecal immunochemical testing was 22%. Faecal immunochemical testing with excellent adherence was superior to colonoscopy every 10 years. Conclusions As novel biological therapies increase colorectal cancer treatment costs, faecal occult blood testing and faecal immunochemical testing could become cost‐saving. The cost‐effectiveness of faecal DNA testing compared with no screening has improved, but faecal occult blood testing and faecal immunochemical testing are preferred to faecal DNA testing when patient adherence is high. Faecal immunochemical testing may be comparable to colonoscopy every 10 years in persons adhering to yearly testing.     

Quantitative colonoscopic evaluation of relative efficiencies of an immunochemical faecal occult blood test and a sensitive guaiac test for detecting significant colorectal neoplasms

Background  The guaiac faecal occult blood test (G-FOBT), HemoccultSENSA, is sensitive for significant neoplasms [colorectal cancer (CRC), advanced adenomatous polyps (AAP)], but faulted by non-specificity for human haemoglobin (Hb). Quantified, Hb- specific, immunochemical faecal occult blood tests (I-FOBT) are now used.
Aims  To (i) compare I-FOBT and G-FOBT efficacy in identifying significant neoplasms and colonoscopy needs for positive tests and (ii) examine number of I-FOBTs needed and test threshold to use for equivalent or better sensitivity than G-FOBT and fewest colonoscopies for positive tests.
Methods  Three daily G-FOBTs and I-FOBTs were collected and analysed in 330 patients scheduled for colonoscopy.
Results  Colonoscopy found significant neoplasms in 32 patients, 6 CRC, 26 AAP. G-FOBT, sensitivity and specificity were 53.1% (17 neoplasms) and 59.4%, resulting in 8.1 colonoscopies/neoplasm. One I-FOBT having ≥50 ngHb/mL of buffer provided equivalent sensitivity but 94.0% specificity, resulting in 2.1 colonoscopies/neoplasm. By analysing the higher of two I-FOBTs at 50 ngHb/mL threshold, sensitivity increased to 68.8% (22 neoplasms, P  = 0.063), specificity fell to 91.9% ( P  < 0.001), but still required 2.1 colonoscopies/neoplasm.
Conclusions  In this population, quantified I-FOBT had significantly better specificity than G-FOBT for significant neoplasms, reducing the number of colonoscopies needed/neoplasm detected. Results depend on the number of I-FOBTs performed and the chosen development threshold.     

Recommendations on population screening for colorectal cancer in New Zealand. Members of the National Health Committee Working Party on Population Screening for Colorectal Cancer

The National Advisory Committee on Health and Disability invited a working party to make recommendations on population screening for colorectal cancer in New Zealand. Recent results from randomised controlled trials of screening with guaiac faecal occult blood tests have provided evidence that population screening could reduce mortality from colorectal cancer. However, given the modest potential level of benefit, the considerable commitment of health sector resources, and the small but real potential for harm, the working party does not recommend population screening for colorectal cancer with faecal occult blood tests in New Zealand. The working party does nto recommend pilot colorectal cancer screening programmes in New Zealand because pilot programmes cannot address the issues of concern: the modest potential benefit and the small, but real, potential for harm. The working party does not recommend faecal occult blood testing as a screening test for colorectal cancer in average-risk individuals outside a population screening programme. Those requesting screening by faecal occult blood test should be given information about the potential risks and benefits. Follow-up bowel investigations in the public health system cannot be guaranteed without an increased allocation of resources. As there is yet no evidence from randomised controlled trials that screening with flexible sigmoidoscopy, colonoscopy or double-contrast barium enema produces a reduction in colorectal cancer mortality, the working party does not recommend population screening with these modalities. Wider consultation and further consideration should be undertaken to develop appropriate advice on surveillance recommendations for groups identified to be at increased risk of colorectal cancer. These decisions should be reviewed as evidence of benefit from new types of faecal occult blood test and other screening modalities becomes available. The working party recognises that colorectal cancer is an important cause of morbidity and mortality and recommends that New Zealand participate in international research in this area.     

Colonoscopy‐controlled intra‐individual comparisons to screen relevant neoplasia: faecal immunochemical test vs. guaiac‐based faecal occult blood test

Aliment Pharmacol Ther 31 , 432–439

Summary

Background Guaiac‐based faecal occult blood tests (g‐FOBTs) are most commonly used in colorectal cancer (CRC) screening programmes. Faecal immunochemical tests (FITs) are thought to be superior. Aim To compare performance of a g‐FOBT and a quantitative FIT for detection of CRCs and advanced adenomas in a colonoscopy‐controlled population. Methods We assessed sensitivity and specificity of both FIT (OC‐sensor) and g‐FOBT (Hemoccult‐II) prior to patients’ scheduled colonoscopies. Results Of the 62 invasive cancers detected in 1821 individuals, g‐FOBT was positive in 46 and FIT in 54 (74.2% vs. 87.1%, P = 0.02). Among 194 patients with advanced adenomas, g‐FOBT was positive in 35 and FIT in 69 (18.0% vs. 35.6%, P < 0.001). Sensitivity for screen relevant tumours (197 advanced adenomas and 28 stage I or II cancers) was 23.0% for g‐FOBT and 40.5% for FIT (P < 0.001). Specificity of g‐FOBT compared to FIT for the detection of cancer was 95.7% vs. 91.0%, P < 0.001) and for advanced adenomas (97.4% vs. 94.2%, P < 0.001). Conclusions Faecal immunochemical test is more sensitive for CRC and advanced adenomas. Sensitivity of FIT for screen relevant tumours, early‐stage cancers and advanced adenomas, is significantly higher. Specificity of g‐FOBT is higher compared with FIT.     

Identification of colorectal adenomas by a quantitative immunochemical faecal occult blood screening test depends on adenoma characteristics, development threshold used and number of tests performed

Background  Faecal occult blood tests (FOBT) are faulted by low sensitivity for advanced adenomatous polyps (AAP). Quantified, immunochemical, haemoglobin (Hb)-specific immunochemical FOBT (I-FOBT) measurements are now used for colorectal screening.
Aims  To correlate adenoma characteristics to amount of faecal Hb lost and to evaluate sensitivity and specificity for AAP by faecal Hb development threshold used and number of I-FOBTs collected.
Methods  Three daily I-FOBTs were collected and analysed in 1221 patients scheduled for colonoscopy. Faecal Hb was analysed as ngHb/mL of buffer and the highest result related to colonoscopy findings.
Results  In 1204 patients without cancer, colonoscopy identified adenomas in 294, 99 with AAPs. Adenoma patients had elevated faecal Hb increasing with advanced histology, size, pedunculated shape and multiplicity ( P < 0.001 for all). At 50 ngHb/mL threshold, sensitivity and specificity for AAPs were 54.5% (95%CI 44.7, 64.7) and 88.1% (95%CI 86.2, 90.1) for three tests. At higher thresholds, sensitivity decreased, but was significantly higher with more samples collected. Conversely, specificity increased at higher thresholds, but decreased with more samples.
Conclusions  Faecal Hb loss from adenomas is significantly associated with size, number and advanced features. Sensitivity and specificity for AAPs are determined by test threshold chosen and number of samples collected; these determine the number of colonoscopies needed for positive tests.     

Screening, prevention and socioeconomic costs associated with the treatment of colorectal cancer

Colorectal cancer (CRC), the third most prevalent cancer worldwide, imposes a significant economic and humanistic burden on patients and society. One study conservatively estimated the annual expenditures for colorectal cancer to be approximately dollars US 5.3 billion in 2000, including both direct and indirect costs. However, other investigators estimated inpatient costs alone incurred in the US in 1994 to be around dollars US 5.14 billion. Therefore, the economic burden of colorectal cancer in the US could be projected to be somewhere in the range of dollars US 5.5-6.5 billion by considering that inpatient costs approximate 80% of total direct costs. No worldwide data have been published, but assuming that the US represents 25-40% of total expenditures in oncology, as seen for breast and lung cancers, a rough estimate for colorectal cancer would be in the range of dollars US 14-22 billion. Screening helps increase patient survival by diagnosing colorectal cancer early. The ideal method among the four tests most used (faecal occult blood test, flexible sigmoidoscopy, colonoscopy and double contrast barium enema) has not been identified. Economic studies of colorectal cancer screening are complex because of the many variables involved, as well as the fact that the outcomes must be followed for many years, and the lack of consensus on screening guidelines. Intuitively, modelling colorectal cancer is one way to overcome these hurdles; published modelling studies predict colorectal cancer screening programs to be within the threshold of dollars US 40000 per life-year saved. The faecal occult blood test appears to be the only clearly effective test, both from a clinical and an economic viewpoint. Important limitations are the invasiveness and inconvenience of the screening procedures, except faecal occult blood test. Patients' comfort and satisfaction are essential in improving compliance with screening recommendations, which appears to be low even in the US (35% of the general population aged over 40 years and 60% of the high-risk population), the country with the highest awareness and compliance in the world. Since colorectal cancer is generally a disease of the elderly, its economic burden is expected to grow in the near future, mainly due to population aging. Potential avenues to pursue in order to contain or reduce the economic burden of colorectal cancer would be the design and implementation of efficient screening programmes, the improvement of patient awareness and compliance with screening guidelines, the development of appropriate prevention programs (i.e. primary and secondary), and earlier diagnosis.     

Influence of non-steroidal anti-inflammatory drugs on the outcome of faecal occult blood tests in screening for colorectal cancer.

Non-steroidal anti-inflammatory drugs have been accused of causing false positive results in faecal occult blood tests for colorectal cancer. A study was therefore performed in 10,931 people undergoing faecal occult blood screening tests to assess the effect of these drugs on the predictive value of a positive test result. Those with a positive result were interviewed and a full drug history was taken before they underwent a full colorectal examination. Of the 455 people with a positive result, 50 were taking non-steroidal anti-inflammatory drugs: 10 (20%) had colonic neoplasia. Of the 405 who were not taking non-steroidal anti-inflammatory drugs, 129 (32%) had colonic neoplasia. These detection rates were not significantly different, and the predictive value of a positive result for an adenoma larger than 1 cm was 14% in the group not taking anti-inflammatory drugs and 26% in the group taking them (not significant). These results suggest that a finding of occult faecal blood cannot be attributed to upper gastrointestinal tract bleeding caused by non-steroidal anti-inflammatory drugs and should be followed by a thorough colorectal examination.     

Review article: Population screening for colorectal cancer

Colorectal cancer is a common cancer and common cause of death. The mortality rate from colorectal cancer can be reduced by identification and removal of cancer precursors, adenomas, or by detection of cancer at an earlier stage. Pilot screening programmes have demonstrated decreased colorectal cancer mortality; as a result many countries are developing colorectal cancer screening programmes. The most common modalities being evaluated are faecal occult blood testing, flexible sigmoidoscopy and colonoscopy. Implementation of screening tests has been hampered by cost, invasiveness, availability of resources and patient acceptance. New technologies such at computed tomographic colonography and stool screening for molecular markers of neoplasia are in development as potential minimally invasive tools. This review considers who should be screened, which test to use and how often to screen.     

Review article: balancing the ideal versus the practical-considerations of colorectal cancer prevention and screening

Colorectal cancer is responsible for over 500 000 deaths annually world-wide. Death from colorectal cancer is preventable, primarily through early diagnosis of disease that has not metastasized. The disease itself may be prevented by the detection and removal of colorectal adenomas, from which more than 95% of colorectal cancers arise. Currently there are several screening methods for the disease. These include faecal occult blood tests, sigmoidoscopy, barium enema and colonscopy as well as emerging methods of virtual colonoscopy and faecal DNA testing. While direct and indirect evidence support the efficacy of these tests they differ from each other in their sensitivity, specificity, cost, and safety. Various professional organizations in different geographical regions of the world have published recommendations on which screening methods to use and when in patients at average- or high-risk. The challenge in reducing the incidence and mortality of this disease lies in increasing accessibility to and compliance with screening and delivery within a quality assured programme.     

The investigation of colorectal disorders.

The investigation of colorectal disorders follows from a thorough clinical examination, examination of stools, and proctosigmoidoscopy. In many patients, barium enema examination will also be required, and the value of good air contrast examinations is stressed. Colonoscopy has revolutionised the diagnostic and therapeutic capabilities in colonic disease, but this examination is not readily available to all, its indications limited, and the risks and discomfort associated with it by no means small. In New Zealand, colorectal cancer is as common as anywhere else in the world, and the major hope of any improvement in this area is with preclinical diagnosis. This could be achieved by more widespread faecal occult blood testing especially in high risk groups (Table 2) and thorough investigation of those with positive results. Serological tests for colorectal cancer (carcino-embryonic antigen) have proved disappointing, and much less specific than originally hoped.     

Can patients at high risk for significant colorectal neoplasms and having normal quantitative faecal occult blood test postpone elective colonoscopy?

Aliment Pharmacol Ther 31 , 523–533

Summary

Background Common reasons for elective screening and surveillance colonoscopy, at predetermined intervals, are family or personal history of colorectal cancer (CRC) or advanced adenoma (AAP). Quantified, human haemoglobin (Hb)‐specific, immunochemical faecal occult blood tests (I‐FOBT) detect bleeding. Aim To determine I‐FOBT sensitivity for CRC or AAP before elective colonoscopy in patients at high‐risk of cancer or advanced adenoma. Methods Prospective double‐blind study of 1000 ambulatory asymptomatic high‐risk patients (555 family history of CRC, 445 surveillance for past neoplasm), who prepared three I‐FOBTs before elective colonoscopy. I‐FOBTs quantified as ngHb/mL of buffer by OC‐MICRO instrument and results ≥50 ngHb/mL considered positive. Results At colonoscopy, eight patients had CRC, 64 others had AAP. Sensitivity for CRC and/or AAP was the highest, 65.3% (95% CI 54.3, 76.3), when any of the three I‐FOBTs was ≥50 ngHb (15.4%), with specificity of 87.5% (95% CI 86.4, 90.5) identifying all CRCs and 62% of AAPs. Conclusions All cancers or an AAP were detected every third I‐FOBT‐positive colonoscopy (47/154), so colonoscopy was potentially not needed at this time in 84.6% (846 patients). I‐FOBT screening might provide effective supervision of high‐risk patients, delaying unnecessary elective colonoscopies. This favourable evaluation needs confirmation and cost–benefit study by risk‐group.     

大便隐血与大肠疾病关系的研究

目的研究大便隐血与大肠疾病的关系,说明大便隐血检测在大肠疾病诊断中的作用。方法收集2012年3月～2014年3月份在上海市松江区九亭医院内镜室行肠镜检查患者粪便隐血实验结果 ,并与肠镜检查结果结合分析粪便隐血与大肠疾病的关系。结果大便隐血在大肠癌、异型增生、炎症性肠病、腺瘤、非腺瘤息肉、肠道炎症及无异常中的阳性率分别为83.33%、83.33%、66.67%、61.67%、39.22%、33.33%、6.16%。大肠癌大便隐血阳性率分别高于非腺瘤息肉、肠道炎症、正常肠黏膜（P〈0.05）。癌前病变（异型增生、腺瘤）大便隐血阳性率分别高于非腺瘤息肉、肠道炎症、正常肠黏膜（P〈0.05）。结论粪便隐血与大肠癌及癌前病变有重要的关系,因此大便隐血实验对于大肠癌及癌前病变的早期筛查有重要意义。     

某社区2013年大肠癌筛查实践

目的:对某社区2013年1月~2013年12月居民大肠癌筛查情况进行分析。方法:采用免疫法粪便潜血FOBT检测以及问卷调查对某社区居民进行筛查,通过初筛和精筛两个步骤来完成大肠癌的筛查,对结果进行分析。结果:823例患者属于高危人群,其阳性率为22.85%;粪便潜血FOBT检测223例患者呈现为阳性,阳性率为6.19%,经过上述两项初次筛查其结果表现为综合分析,最终明确2551人列入到高危人群,其高危阳性率为70.82%;1500例患者接受了电子结肠镜检查,受检率为58.80%,发现息肉、息肉样增生近1000例,发现直、结肠癌40例,中重度异型增生等癌前病变110例,肠镜检查率为76.67%。在40~49岁年龄组中其大肠病变的检出率为30.21%,年龄≥70岁中大肠病变的检出率最高,达到了58.37%。男性患者肠镜检出率达到了56.37%,而女性患者明显较低,只有37.65%。结论:某社区居民大肠癌的发病率相对来说较高,并且年龄越大发病率越高,男性发病率高于女性,应加大宣传力度,提高防治意识。     

A comparison of the acceptance of immunochemical faecal occult blood test and colonoscopy in colorectal cancer screening: a prospective study among Chinese

Aliment Pharmacol Ther 2010; 32: 74–82

Summary

Background Preferences to choose immunochemical faecal occult blood test (FIT) and colonoscopy as colorectal cancer (CRC) screening modalities among asymptomatic Chinese subjects remain unknown. Aim To evaluate the preference of choosing colonoscopy vs. FIT among CRC screening participants. Methods From a community‐based CRC screening programme for asymptomatic Hong Kong Chinese aged 50–70 years, participants attended standardized educational sessions and chose the options of annual FIT for 5 years or direct colonoscopy once. Factors associated with choosing colonoscopy were evaluated by multivariate regression analysis. Results Among 3430 participants [mean age 56.8 years (s.d. 5.0); female 55.1%, male 44.9%], 51.3% chose colonoscopy and 48.7% chose FIT. Older participants (65–70 years) were less likely to choose colonoscopy [adjusted odds ratio (aOR) 0.731, P = 0.041]. Subjects who chose colonoscopy were those disagreed screening would lead to discomfort (aOR 1.356, P < 0.001), had relatives or friends who had CRC (first degree relatives aOR 1.679, P < 0.001; second degree relatives aOR 1.304, P = 0.019; friends or others aOR 1.252, P = 0.026) and those who self‐perceived their health as poor (aOR 1.529, P = 0.025). Conclusions Faecal occult blood test and direct colonoscopy were equally preferable to Chinese. Colonoscopy was preferred among the younger subjects, those with positive family history of CRC and self‐perceived poor health status.     

上海市某社区中老年粪便潜血阳性的相关预测因素

目的：研究影响中老年人粪便潜血试验结果的相关预测因素。方法：回顾性分析2013－2014年上海市静安区石门二路街道社区卫生服务中心接受结直肠癌筛查居民的相关资料,并对相关因素进行单因素及多因素分析。结果：Logistic回归分析表明年龄、黏液或血便史、肠息肉史是影响粪便潜血结果的主要因素（P＜0.05）。结论：社区中,老年人、有黏液血便史或肠息肉史者应定期进行粪便潜血检查,对促进结直肠癌的早期诊治具有重要意义。     

Should we be screening for colorectal cancer?

Mass population screening for asymptomatic neoplastic disease is now national policy in the UK for breast cancer and has been established for many years in the early diagnosis of carcinoma of the cervix. Cancer screening is based on the concept that treatment is more effective when the disease is localised and aims to detect it when it is at a less advanced clinico-pathological stage prior to the development of symptoms. Because colorectal cancer develops in benign adenomatous polyps which are often amenable to endoscopic resection, screening may both reduce the incidence of the disease as well as improving outcome from it. Flexible sigmoidoscopy screening focuses mainly on the detection of potentially malignant adenomas, their endoscopic removal producing a decrease in colorectal cancer incidence. It is a promising approach but conclusive data on effectiveness from a Medical Research Council-sponsored multicentre randomised controlled trial will not be available before 2006. Faecal occult blood testing aims to preferentially detect early stage invasive disease. Three randomised controlled trials of faecal occult blood screening show that the disease can be detected earlier in its development leading to reduced mortality from the disease--and that this is achieved at reasonable cost. The Department of Health is currently giving consideration to its national implementation.