Faecal immunochemical tests (FIT) versus colonoscopy for surveillance after screening and polypectomy: a diagnostic accuracy and cost-effectiveness study

OBJECTIVE

The English Bowel Cancer Screening Programme (BCSP) recommends 3 yearly colonoscopy surveillance for patients at intermediate risk of colorectal cancer (CRC) postpolypectomy (those with three to four small adenomas or one ≥10 mm). We investigated whether faecal immunochemical tests (FITs) could reduce surveillance burden on patients and endoscopy services.

DESIGN

Intermediate-risk patients (60-72 years) recommended 3 yearly surveillance were recruited within the BCSP (January 2012-December 2013). FITs were offered at 1, 2 and 3 years postpolypectomy. Invitees consenting and returning a year 1 FIT were included. Participants testing positive (haemoglobin ≥40 µg/g) at years one or two were offered colonoscopy early; all others were offered colonoscopy at 3 years. Diagnostic accuracy for CRC and advanced adenomas (AAs) was estimated considering multiple tests and thresholds. We calculated incremental costs per additional AA and CRC detected by colonoscopy versus FIT surveillance.

RESULTS

74% (5938/8009) of invitees were included in our study having participated at year 1. Of these, 97% returned FITs at years 2 and 3. Three-year cumulative positivity was 13% at the 40 µg/g haemoglobin threshold and 29% at 10 µg/g. 29 participants were diagnosed with CRC and 446 with AAs. Three-year programme sensitivities for CRC and AAs were, respectively, 59% and 33% at 40 µg/g, and 72% and 57% at 10 µg/g. Incremental costs per additional AA and CRC detected by colonoscopy versus FIT (40 µg/g) surveillance were £7354 and £180 778, respectively.

CONCLUSIONS

Replacing 3 yearly colonoscopy surveillance in intermediate-risk patients with annual FIT could reduce colonoscopies by 71%, significantly cut costs but could miss 30%-40% of CRCs and 40%-70% of AAs.

TRIAL REGISTRATION NUMBER

ISRCTN18040196; Results.

Effect of once-only flexible sigmoidoscopy screening on the outcomes of subsequent faecal occult blood test screening

OBJECTIVE

To investigate the outcomes of biennial guaiac faecal occult blood test (gFOBT) screening after once-only flexible sigmoidoscopy (FS) screening.

METHODS

Between 1994 and 1999, as part of the UK FS Screening Trial (UKFSST), adults aged 55-64 were randomly allocated to an intervention group (offered FS screening) or a control group (not contacted). From 2006, a subset of UKFSST participants (20,895/44,041 intervention group; 41,497/87,149 control group) were invited to biennial gFOBT screening by the English Bowel Cancer Screening Programme. We analysed gFOBT uptake, test positivity, yield of colorectal cancer (CRC), and positive predictive value (PPV) for CRC, advanced adenomas (AAs), and advanced colorectal neoplasia (ACN: AA/CRC).

RESULTS

Uptake of gFOBT at first invitation was 1.9% lower (65.7% vs. 67.6%, p < 0.01) among intervention versus control group participants. Positivity was 0.4% lower (2.0% vs. 2.4%, p < 0.01) and CRC yield was 0.08% lower (0.19% vs. 0.27%, p = 0.14). PPVs were also lower in the intervention versus control group, at 10.3% vs. 12.3% ( p = 0.44) for CRC, 22.7% vs. 31.4% ( p < 0.01) for AA, and 33.0% vs. 43.7% ( p < 0.01) for ACN. Among those who refused FS ( n = 5532), gFOBT uptake at first invitation was 47.7%, CRC yield was 0.25%, and PPV for ACN was 46.2%. Among FS attenders ( n = 15,363), uptake was 72.2%, CRC yield was 0.18%, and PPV for ACN was 27.9%.

CONCLUSIONS

Uptake, positivity and PPV of gFOBT screening were reduced following prior offer of FS screening. However, a quarter of FS screened participants receiving a diagnostic examination after positive gFOBT were diagnosed with ACN.

High test positivity and low positive predictive value for colorectal cancer of continued faecal occult blood test screening after negative colonoscopy

Objectives The English Bowel Cancer Screening Programme offers biennial guaiac faecal occult blood test (gFOBT) screening to 60-74-year-olds. Participants with positive results are referred for follow-up, but many do not have significant findings. If they remain age eligible, these individuals are reinvited for gFOBT screening. We evaluated the performance of repeat screening in this group. Methods We analysed data on programme participants reinvited to gFOBT screening after either previous negative gFOBT ( n = 327,542), or positive gFOBT followed by a diagnostic investigation negative for colorectal cancer (CRC) or adenomas requiring surveillance ( n = 42,280). Outcomes calculated were uptake, test positivity, yield of CRC, and positive predictive value (PPV) of gFOBT for CRC. Results For participants with a previous negative gFOBT, uptake in the subsequent screening round was 87.5%, positivity was 1.3%, yield of CRC was 0.112% of those adequately screened, and the PPV of gFOBT for CRC was 9.1%. After a positive gFOBT and a negative diagnostic investigation, uptake in the repeat screening round was 82.6%, positivity was 11.3%, CRC yield was 0.172% of participants adequately screened, and the PPV of gFOBT for CRC was 1.7%. Conclusion With high positivity and low PPV for CRC, the suitability of routine repeat gFOBT screening in two years among individuals with a previous positive test and a negative diagnostic examination needs to be carefully considered.

British Society of Gastroenterology position statement on serrated polyps in the colon and rectum

Serrated polyps have been recognised in the last decade as important premalignant lesions accounting for between 15% and 30% of colorectal cancers. There is therefore a clinical need for guidance on how to manage these lesions; however, the evidence base is limited. A working group was commission by the British Society of Gastroenterology (BSG) Endoscopy section to review the available evidence and develop a position statement to provide clinical guidance until the evidence becomes available to support a formal guideline. The scope of the position statement was wide-ranging and included: evidence that serrated lesions have premalignant potential; detection and resection of serrated lesions; surveillance strategies after detection of serrated lesions; special situations-serrated polyposis syndrome (including surgery) and serrated lesions in colitis; education, audit and benchmarks and research questions. Statements on these issues were proposed where the evidence was deemed sufficient, and re-evaluated modified via a Delphi process until >80% agreement was reached. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool was used to assess the strength of evidence and strength of recommendation for finalised statements. Key recommendation: we suggest that until further evidence on the efficacy or otherwise of surveillance are published, patients with sessile serrated lesions (SSLs) that appear associated with a higher risk of future neoplasia or colorectal cancer (SSLs ≥10 mm or serrated lesions harbouring dysplasia including traditional serrated adenomas) should be offered a one-off colonoscopic surveillance examination at 3 years (weak recommendation, low quality evidence, 90% agreement).

Appearances of screen-detected versus symptomatic colorectal cancers at CT colonography

OBJECTIVES

The aim of this study was to compare the morphology, radiological stage, conspicuity, and computer-assisted detection (CAD) characteristics of colorectal cancers (CRC) detected by computed tomographic colonography (CTC) in screening and symptomatic populations.

METHODS

Two radiologists independently analyzed CTC images from 133 patients diagnosed with CRC in (a) two randomized trials of symptomatic patients (35 patients with 36 tumours) and (b) a screening program using fecal occult blood testing (FOBt; 98 patients with 100 tumours), measuring tumour length, volume, morphology, radiological stage, and subjective conspicuity. A commercial CAD package was applied to both datasets. We compared CTC characteristics between screening and symptomatic populations with multivariable regression.

RESULTS

Screen-detected CRC were significantly smaller (mean 3.0 vs 4.3 cm, p < 0.001), of lower volume (median 9.1 vs 23.2 cm3, p < 0.001) and more frequently polypoid (34/100, 34 % vs. 5/36, 13.9 %, p = 0.02) than symptomatic CRC. They were of earlier stage than symptomatic tumours (OR = 0.17, 95 %CI 0.07-0.41, p < 0.001), and were judged as significantly less conspicuous (mean conspicuity 54.1/100 vs. 72.8/100, p < 0.001). CAD detection was significantly lower for screen-detected (77.4 %; 95 %CI 67.9-84.7 %) than symptomatic CRC (96.9 %; 95 %CI 83.8-99.4 %, p = 0.02).

CONCLUSIONS

Screen-detected CRC are significantly smaller, more frequently polypoid, subjectively less conspicuous, and less likely to be identified by CAD than those in symptomatic patients.

KEY POINTS

• Screen-detected colorectal cancers (CRC) are significantly smaller than symptomatic CRC. • Screening cases are significantly less conspicuous to radiologists than symptomatic tumours. • Screen-detected CRC have different morphology compared to symptomatic tumours (more polypoid, fewer annular). • A commercial computer-aided detection (CAD) system was significantly less likely to note screen-detected CRC.

Recommendations for a step-wise comparative approach to the evaluation of new screening tests for colorectal cancer

BACKGROUND

New screening tests for colorectal cancer continue to emerge, but the evidence needed to justify their adoption in screening programs remains uncertain.

METHODS

A review of the literature and a consensus approach by experts was undertaken to provide practical guidance on how to compare new screening tests with proven screening tests.

RESULTS

Findings and recommendations from the review included the following: Adoption of a new screening test requires evidence of effectiveness relative to a proven comparator test. Clinical accuracy supported by programmatic population evaluation in the screening context on an intention-to-screen basis, including acceptability, is essential. Cancer-specific mortality is not essential as an endpoint provided that the mortality benefit of the comparator has been demonstrated and that the biologic basis of detection is similar. Effectiveness of the guaiac-based fecal occult blood test provides the minimum standard to be achieved by a new test. A 4-phase evaluation is recommended. An initial retrospective evaluation in cancer cases and controls (Phase 1) is followed by a prospective evaluation of performance across the continuum of neoplastic lesions (Phase 2). Phase 3 follows the demonstration of adequate accuracy in these 2 prescreening phases and addresses programmatic outcomes at 1 screening round on an intention-to-screen basis. Phase 4 involves more comprehensive evaluation of ongoing screening over multiple rounds. Key information is provided from the following parameters: the test positivity rate in a screening population, the true-positive and false-positive rates, and the number needed to colonoscope to detect a target lesion.

CONCLUSIONS

New screening tests can be evaluated efficiently by this stepwise comparative approach.

European Code against Cancer, 4th Edition: Cancer screening

In order to update the previous version of the European Code against Cancer and formulate evidence-based recommendations, a systematic search of the literature was performed according to the methodology agreed by the Code Working Groups. Based on the review, the 4th edition of the European Code against Cancer recommends: "Take part in organized cancer screening programmes for: Bowel cancer (men and women); Breast cancer (women); Cervical cancer (women)." Organized screening programs are preferable because they provide better conditions to ensure that the Guidelines for Quality Assurance in Screening are followed in order to achieve the greatest benefit with the least harm. Screening is recommended only for those cancers where a demonstrated life-saving effect substantially outweighs the potential harm of examining very large numbers of people who may otherwise never have, or suffer from, these cancers, and when an adequate quality of the screening is achieved. EU citizens are recommended to participate in cancer screening each time an invitation from the national or regional screening program is received and after having read the information materials provided and carefully considered the potential benefits and harms of screening. Screening programs in the European Union vary with respect to the age groups invited and to the interval between invitations, depending on each country's cancer burden, local resources, and the type of screening test used For colorectal cancer, most programs in the EU invite men and women starting at the age of 50-60 years, and from then on every 2 years if the screening test is the guaiac-based fecal occult blood test or fecal immunochemical test, or every 10 years or more if the screening test is flexible sigmoidoscopy or total colonoscopy. Most programs continue sending invitations to screening up to the age of 70-75 years. For breast cancer, most programs in the EU invite women starting at the age of 50 years, and not before the age of 40 years, and from then on every 2 years until the age of 70-75 years. For cervical cancer, if cytology (Pap) testing is used for screening, most programs in the EU invite women starting at the age of 25-30 years and from then on every 3 or 5 years. If human papillomavirus testing is used for screening, most women are invited starting at the age of 35 years (usually not before age 30 years) and from then on every 5 years or more. Irrespective of the test used, women continue participating in screening until the age of 60 or 65 years, and continue beyond this age unless the most recent test results are normal.

Prolonged biologically active colonic tissue levels of curcumin achieved after oral administration--a clinical pilot study including assessment of patient acceptability

Curcumin, the main constituent of turmeric, is suspected to possess cancer chemopreventive properties. Pharmacokinetic and pharmacodynamic parameters have been reported, but few data exist describing whether methodologies are suitably robust for curcuminoid detection in colonic biopsy specimens. Information on the acceptability of prolonged administration of daily curcumin is not available. This is of vital importance to implement chemoprevention strategies. This study aimed to quantify levels of curcuminoids in colorectal mucosa of patients undergoing colorectal endoscopy or surgical resection and to obtain information on the acceptability and compliance with daily curcumin. Curcumin C3 complex (2.35 g) was administered to patients once daily for 14 days before endoscopic biopsy or colonic resection. Safety and tolerance were monitored. Analysis of curcuminoids in plasma, urine, and colonic mucosa was conducted by ultraperformance liquid chromatography (UPLC)-UV with characterization by liquid chromatography/tandem mass spectrometry (LC/MS-MS). Twenty-four of 26 patients commencing curcumin completed the course. Six patients reported mild gastrointestinal adverse events. Curcuminoids were detectable in nine of 24 plasma samples, 24 of 24 urine samples, and in the colonic mucosa of all 23 biopsied participants. Mean tissue levels were 48.4 μg/g (127.8 nmol/g) of parent curcuminoids. The major conjugate, curcumin glucuronide, was detectable in 29 of 35 biopsies. High levels of topical curcumin persisted in the mucosa for up to 40 hours postadministration. Sixteen participants (67%) stated that they would take curcumin long-term should it be of proven benefit. In summary, pharmacologically active levels of curcumin were recovered from colonic mucosa. The regimen used here seems safe, and patients support its use in long-term trials.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Colonoscopic surveillance following adenoma removal

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on colonoscopic surveillance following adenoma removal includes 24 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of surveillance and other elements in the screening process, including multi-disciplinary diagnosis and management of the disease.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Quality assurance in endoscopy in colorectal cancer screening and diagnosis

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on quality assurance in endoscopy includes 50 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of endoscopy and other elements in the screening process, including multidisciplinary diagnosis and management of the disease.

Toward standardizing and reporting colorectal cancer screening indicators on an international level: The International Colorectal Cancer Screening Network

The International Colorectal Cancer Screening Network was established in 2003 to promote best practice in the delivery of organized colorectal cancer screening programs. To facilitate evaluation of such programs, we defined a set of universally applicable colorectal cancer screening measures and indicators. To test the feasibility of data collection, we requested data on these variables and basic program characteristics from 26 organized full programs and 9 pilot programs in 24 countries. The size of the target population for each program varied considerably from a few thousand to 36 million. The majority of programs used fecal occult blood tests for primary screening, with more using guaiac than immunochemical tests. There was wide variation in the ability of screening programs to report the requested measures and in the values reported. In general, pilot programs were more likely to provide screening measure values than were full programs. As expected, detection rates for polyps and neoplasia were substantially higher in programs screening with endoscopy than in those using fecal occult blood tests. It is hoped that the screening measures and indicators, once revised in the light of this survey, will be adopted and used by existing programs and those in the early planning stages, allowing international comparison with the goal of improved colorectal cancer screening quality.

Once-only sigmoidoscopy in colorectal cancer screening: follow-up findings of the Italian Randomized Controlled Trial--SCORE

BACKGROUND

A single flexible sigmoidoscopy at around the age of 60 years has been proposed as an effective strategy for colorectal cancer (CRC) screening.

METHODS

We conducted a randomized controlled trial to evaluate the effect of flexible sigmoidoscopy screening on CRC incidence and mortality. A questionnaire to assess the eligibility and interest in screening was mailed to 236,568 men and women, aged 55-64 years, who were randomly selected from six trial centers in Italy. Of the 56,532 respondents, interested and eligible subjects were randomly assigned to the intervention group (invitation for flexible sigmoidoscopy; n = 17,148) or the control group (no further contact; n = 17,144), between June 14, 1995, and May 10, 1999. Flexible sigmoidoscopy was performed on 9911 subjects. Intention-to-treat and per-protocol analyses were performed to compare the CRC incidence and mortality rates in the intervention and control groups. Per-protocol analysis was adjusted for noncompliance.

RESULTS

A total of 34,272 subjects (17,136 in each group) were included in the follow-up analysis. The median follow-up period was 10.5 years for incidence and 11.4 years for mortality; 251 subjects were diagnosed with CRC in the intervention group and 306 in the control group. Overall incidence rates in the intervention and control groups were 144.11 and 176.43, respectively, per 100,000 person-years. CRC-related death was noted in 65 subjects in the intervention group and 83 subjects in the control group. Mortality rates in the intervention and control groups were 34.66 and 44.45, respectively, per 100,000 person-years. In the intention-to-treat analysis, the rate of CRC incidence was statistically significantly reduced in the intervention group by 18% (rate ratio [RR] = 0.82, 95% confidence interval [CI] = 0.69 to 0.96), and the mortality rate was non-statistically significantly reduced by 22% (RR = 0.78; 95% CI = 0.56 to 1.08) compared with the control group. In the per-protocol analysis, both CRC incidence and mortality rates were statistically significantly reduced among the screened subjects; CRC incidence was reduced by 31% (RR = 0.69; 95% CI = 0.56 to 0.86) and mortality was reduced by 38% (RR = 0.62; 95% CI = 0.40 to 0.96) compared with the control group.

CONCLUSION

A single flexible sigmoidoscopy screening between ages 55 and 64 years was associated with a substantial reduction of CRC incidence and mortality.

The impact of individually-tailored lifestyle advice in the colorectal cancer screening context: a randomised pilot study in North-West London

OBJECTIVE

The screening context may provide a "teachable moment" for promoting health behaviours. The present study examined the impact on diet, alcohol and physical activity of providing individually-tailored advice in the context of flexible sigmoidoscopy (FS) screening.

METHOD

Adults (n=365) aged 58-59 years who attended FS screening between 2006 and 2008 and had no abnormalities detected were randomised to one of three groups: (i) control (usual care); (ii) standard leaflet on healthy lifestyle; or (iii) standard leaflet plus brief, tailored feedback based on information from the pre-screening questionnaire. A 6-month follow-up questionnaire assessed group differences in fruit and vegetable consumption, alcohol intake and physical activity.

RESULTS

More people in the tailored group were meeting the 5-a-day fruit and vegetable recommendation at 6 months (OR: 2.28, CI[1.09, 4.76]). For physical activity there was a non-significant trend towards meeting current activity guidelines in the tailored group (OR: 1.26, CI[0.62, 2.55]). Alcohol intake was low overall and did not change in any group.

CONCLUSION

Tailored advice given in the context of cancer screening may provide an opportunity to improve dietary behaviours. Further research is needed to determine whether screening provides a unique "teachable moment" or if similar effects can be achieved in other health settings.

Improving colorectal cancer screening outcomes: Proceedings of the second meeting of the International Colorectal Cancer Screening Network, a global quality initiative

The International Colorectal Cancer Screening Network (ICRCSN) is a global consortium of initiatives delivering organized colorectal cancer (CRC) screening to their populations. The aim of the Network is to promote improvements in quality assurance (QA) and programme evaluation to maximize the benefit and to minimize the risk associated with CRC screening. ICRCSN currently includes 41 member initiatives from 27 countries. The ICRCSN held its second international meeting in Oxford in September 2008 with representatives from 24 countries. This report summarizes the presentations and discussions, the feedback from participants on their current and future needs and the potential role of the ICRCSN in supporting those needs.

Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial

BACKGROUND

Colorectal cancer is the third most common cancer worldwide and has a high mortality rate. We tested the hypothesis that only one flexible sigmoidoscopy screening between 55 and 64 years of age can substantially reduce colorectal cancer incidence and mortality.

METHODS

This randomised controlled trial was undertaken in 14 UK centres. 170 432 eligible men and women, who had indicated on a previous questionnaire that they would accept an invitation for screening, were randomly allocated to the intervention group (offered flexible sigmoidoscopy screening) or the control group (not contacted). Randomisation by sequential number generation was done centrally in blocks of 12, with stratification by trial centre, general practice, and household type. The primary outcomes were the incidence of colorectal cancer, including prevalent cases detected at screening, and mortality from colorectal cancer. Analyses were intention to treat and per protocol. The trial is registered, number ISRCTN28352761.

FINDINGS

113 195 people were assigned to the control group and 57 237 to the intervention group, of whom 112 939 and 57 099, respectively, were included in the final analyses. 40 674 (71%) people underwent flexible sigmoidoscopy. During screening and median follow-up of 11.2 years (IQR 10.7-11.9), 2524 participants were diagnosed with colorectal cancer (1818 in control group vs 706 in intervention group) and 20 543 died (13 768 vs 6775; 727 certified from colorectal cancer [538 vs 189]). In intention-to-treat analyses, colorectal cancer incidence in the intervention group was reduced by 23% (hazard ratio 0.77, 95% CI 0.70-0.84) and mortality by 31% (0.69, 0.59-0.82). In per-protocol analyses, adjusting for self-selection bias in the intervention group, incidence of colorectal cancer in people attending screening was reduced by 33% (0.67, 0.60-0.76) and mortality by 43% (0.57, 0.45-0.72). Incidence of distal colorectal cancer (rectum and sigmoid colon) was reduced by 50% (0.50, 0.42-0.59; secondary outcome). The numbers needed to be screened to prevent one colorectal cancer diagnosis or death, by the end of the study period, were 191 (95% CI 145-277) and 489 (343-852), respectively.

INTERPRETATION

Flexible sigmoidoscopy is a safe and practical test and, when offered only once between ages 55 and 64 years, confers a substantial and longlasting benefit.

FUNDING

Medical Research Council, National Health Service R&D, Cancer Research UK, KeyMed.

Perceived barriers to flexible sigmoidoscopy screening for colorectal cancer among UK ethnic minority groups: a qualitative study

OBJECTIVES

Evidence from existing UK screening programmes indicates disparities in uptake rates between UK ethnic minorities and the white majority population. The aim of this study was to explore barriers to the uptake of flexible sigmoidoscopy (FS) screening among UK ethnic minority populations. Specifically, beliefs about bowel cancer, perceived barriers to the test and ideas about ways to increase uptake were investigated.

METHODS

Nine focus groups were conducted with a total of 53 participants from African-Caribbean, Gujarati Indian, Pakistani and white British communities. The topic guide was based on the Health Belief Model. Discussions were subject to framework analysis.

RESULTS

Most participants expressed limited awareness of bowel cancer and cited this as a barrier to screening attendance. Anxiety regarding the invasiveness of the test, the bowel preparation and fear of a cancer diagnosis were common barriers across all ethnic groups. Language difficulties, failure to meet religious sensitivities and the expression of culturally influenced health beliefs were all discussed as specific barriers to uptake. Ethnically tailored health promotion and general practitioner involvement were recommended as ways of overcoming such barriers.

CONCLUSIONS

The study was the first attempt to qualitatively explore barriers to FS bowel cancer screening in UK ethnic minorities. Most barriers were shared by all ethnic groups but health educators should supplement approaches designed for the majority to incorporate the specific needs of individual minority groups to ensure equitable access.

The psychological impact of being offered surveillance colonoscopy following attendance at colorectal screening using flexible sigmoidoscopy

OBJECTIVES

To examine the psychological impact of being assigned to colonoscopic surveillance following detection of adenomatous polyps at flexible sigmoidoscopy (FS) screening.

SETTING

Participants invited for screening in 12 of the 14 study centres in the UK FS Trial.

METHODS

A postal survey following FS screening assessed bowel cancer worry, psychological distress, generalized anxiety, bowel symptoms, general practitioner (GP) visits, positive emotional consequences of screening, and reassurance among people with no polyps (n = 26,573), lower-risk polyps removed at FS (n = 7401) and higher-risk polyps who underwent colonoscopy and were either assigned to colonoscopic surveillance (n = 1543) or discharged (n = 183). A sub-sample (n = 6389) also completed a questionnaire prior to screening attendance that measured bowel cancer worry, generalized anxiety, bowel symptoms and GP visits, making it possible to examine longitudinal changes in this group.

RESULTS

People offered surveillance reported lower psychological distress and anxiety than those with either no polyps or lower-risk polyps. The surveillance group also reported more positive emotional benefits of screening than the other outcome groups. Post-screening bowel cancer worry and bowel symptoms were higher in people assigned to surveillance, but both declined over time, reaching levels observed in either one or both of the other two groups found to have polyps, suggesting these results were a consequence of polyp detection rather than surveillance per se. Few differences were observed between the group assigned surveillance and the group discharged following colonoscopy.

CONCLUSION

The results of the current study are broadly reassuring and indicate that referral for colonoscopic surveillance is not associated with adverse psychological consequences.

Choosing between CT colonography and colonoscopy in the diagnostic context: a qualitative study of influences on patient preferences

OBJECTIVE

To explore information needs and preferences on diagnostic bowel tests and elicit preferences for CT colonography (CTC) vs. colonoscopy (CC).

BACKGROUND

CTC is a new technology for large-bowel imaging that has been widely assumed to be more acceptable than CC because it is non-invasive.

DESIGN

Semi-structured focus groups discussing information choices and procedure preferences.

SETTING AND PARTICIPANTS

Non-patient sample of 26 asymptomatic volunteers (mean age 64 years).

MAIN OUTCOME MEASURES

Information choices and CC-vs.-CTC preferences were recorded following stepwise presentation of different test attributes. Qualitative thematic analysis was used to examine transcripts of group discussions.

RESULTS

On the basis of minimal information about the two tests, a majority of participants preferred CTC to CC (65% vs. 11%), while 24% had no preference. However, once they had received information on all aspects, this was reversed, with 80% of participants preferring CC compared with 8% preferring CTC. Thematic analysis of the discussion showed that participants almost unanimously considered information about test sensitivity to be the most important feature, and perceived relatively modest differences in test sensitivity to be highly significant. Information about risks and side-effects was considered to be the second most important aspect and attracted questions about risks of bowel perforation and health consequences following exposure to radiation.

CONCLUSIONS

Patients place high value on quality rather than comfort for medical investigations. This has important implications for the development of educational materials supporting informed choice as well as future directions in refinement of CTC technology.

Colorectal cancer screening: a comparison of 35 initiatives in 17 countries

Although in its infancy, organized screening for colorectal cancer (CRC) in the general population is increasing at regional and national levels. Documenting and describing these initiatives is critical to identifying, sharing and promoting best practice in the delivery of CRC screening. Subsequently, the International Colorectal Cancer Screening Network (ICRCSN) was established in 2003 to promote best practice in the delivery of organized screening programs. The initial aim was to identify and document organized screening initiatives that commenced before May 2004. Each identified initiative was sent 1 questionnaire per screening modality: fecal occult blood test, flexible sigmoidoscopy or total colonoscopy. Information was collected on screening methodology, testing details and initiative status. In total, 35 organized initiatives were identified in 17 countries, including 10 routine population-based screening programs, 9 pilots and 16 research projects. Fecal occult blood tests were the most frequently used screening modality, and total colonoscopy was seldom used as a primary screening test. The eligible age for screening ranged from 40 years old to no upper limit; most initiatives included participants aged 50 to 64. Recruitment was usually done by a mailed invitation or during a visit to a family physician. In conclusion, this is the first investigation describing the delivery of CRC screening protocols to various populations. The work of the ICRCSN is enabling valuable information to be shared and a common nomenclature to be established.

Findings at Follow-up Endoscopies in Subjects With Suspected Colorectal Abnormalities: Effects of Baseline Findings and Time to Follow-up

PURPOSE

Guidelines for colonoscopic surveillance after the removal of colorectal polyps already exist in the United Kingdom and United States. However, there is a continuing need to build up an evidence base on the likely effect of different follow-up policies for specific current findings. This article reports on the colonoscopic surveillance of a cohort of patients in Taiwan. The risk of various outcomes at the second examination is assessed according to findings at the first examination and the interval between examinations.

PATIENTS AND METHODS

Data from baseline and follow-up examinations for 2,287 individuals attending the National Taiwan University Hospital were collected retrospectively. Multivariate logistic regression was used to identify risk factors for the following 4 outcomes: any positive findings; multiple (> or =3) polyps; large (> or =10 mm) polyp(s); or villous adenoma(s) or cancer. The effect of the interval between examinations was assessed in all models.

RESULTS

Older age was an independent risk factor for all outcomes. The number of baseline polyps was a significant risk factor for both positive results and multiple polyps, more severe baseline histology was a risk factor for large polyps and villous adenomas/cancer, and larger baseline polyps were a risk factor for large polyps at follow-up. Interval time was only an independent risk factor for villous adenomas/cancer, which tended to be found at shorter follow-up times. The total number of abnormalities found at follow-up was significantly related to the number of follow-up examinations but not to the total follow-up time.

CONCLUSIONS

Results suggest that, with the possible exception of subjects with villous adenomas at baseline, most reexaminations can safely be delayed for > or =5 years. In the majority of cases staff at the hospital were correctly identifying those subjects at particularly high risk and assigning shorter follow-up intervals accordingly. Models indicate that many of the findings seen at follow-up were due to missed baseline findings.

Role of NQO1C609T and EPHX1 gene polymorphisms in the association of smoking and alcohol with sporadic distal colorectal adenomas: results from the UKFSS Study

NADP(H):quinone oxidoreductase 1 (NQO1) and microsomal epoxide hydrolase (EPHX1, also mEH) are attractive candidate enzymes for association with colorectal neoplasia because they metabolize a number of compounds including polycyclic aromatic hydrocarbons (PAHs) that have been linked with colorectal carcinogenesis. We examined the relationship between NQO1C609T, mEH3, mEH4 and risk of sporadic distal colorectal adenomas in one of the largest case-control studies of 946 polyp-free controls and 894 cases, all participants of the UK Flexible Sigmoidoscopy Screening (UKFSS) Trial. The polymorphisms were examined as independent risk factors and evidence for interaction with smoking and alcoholic drinks was sought. The NQO1 609*T allele was positively associated with high-risk adenoma in this population [odds ratio (OR), 1.36; 95% confidence interval (CI), 1.02-1.83]. Elevated risk estimates were seen in smokers independently of the genotype but the association was stronger among current smokers with the heterozygous variant genotype (OR, 4.24; 95% CI, 2.54-7.09). It was reported for the first time that the association between alcohol and colorectal adenoma was modified by NQO1C609T genotype, such that the relation between alcohol and colorectal adenoma was stronger among those with the common C/C genotype (OR, 1.49; 95% CI, 1.11-2.02; P-interaction = 0.024). There was no association between mEH3 and mEH4 variants and colorectal adenoma risk and no effect modification by alcohol and smoking. These findings provide evidence for an important role of the NQO1C609T polymorphism in susceptibility of colorectal adenomas. Alcohol increases risk of colorectal adenoma in carriers of the high-activity genotype possibly through enhanced activation of alcohol-related procarcinogens.

MTHFR (C677T and A1298C) Polymorphisms and Risk of Sporadic Distal Colorectal Adenoma in the UK Flexible Sigmoidoscopy Screening Trial (United Kingdom)

OBJECTIVE

The purpose of this study was to further evaluate the role of low activity MTHFR variants as well as to explore interactive effects between alcoholic drink consumption and MTHFR variants and risk of distal colorectal adenomatous polyps.

METHODS

We examined the relationship between MTHFR C677T and A1298C gene polymorphisms and risk of distal adenomas in one of the largest case control studies of 946 polyp-free controls and 894 cases, all participants of the UK Flexible Sigmoidoscopy Screening Trial (UKFSS).

RESULTS

Investigation of the effect of the MTHFR C677T polymorphism in this large UKFSS study revealed no overall association on adenoma risk (P>0.05). However the MTHFR 1298C allele was linked, for the first time, to high risk adenomas, although in males only (odds ratio (OR) for A/C+C/C compared with A/A 1.55; 95% confidence interval (CI), 1.08-2.22; P=0.018).

CONCLUSIONS

In this, the largest study of these polymorphisms in relation to colorectal adenoma, there was no evidence for an interaction with alcohol in combination with the variant forms of MTHFR (P>0.05).

Effective screening for bowel cancer: a United kingdom perspective

Bowel cancer is a major cause of morbidity and death and is a high cost to health care systems. Screening currently offers the best chance of improving outcomes from bowel cancer. When introducing screening, the problems encountered in other cancers need to be avoided to maximize benefits and minimize harms.

The effect of cigarette smoking use and cessation on serum insulin-like growth factors

The patterns of risk association between circulating levels of insulin-like growth factor (IGF)-I, and its main binding protein, IGFBP-3, differ between smoking and nonsmoking-related cancers. To investigate this observation further, we measured serum IGF-I, IGF-II and IGF-binding protein-3 concentrations in 232 men and 210 women (aged 55-64 years), and related peptide levels to smoking characteristics. Current smoking was associated with significant reductions in mean IGFBP-3 levels in men assessed by the number of cigarettes smoked daily (P(trend)=0.007) and pack-years smoked (P(trend)=0.03). Mean IGF-I levels decreased with increasing cigarette use in men (P(trend)=0.11). There were no patterns of association between smoking and IGF peptides in women. For male former vs never smokers, there were no differences in mean IGF-I and IGFBP-3 concentrations, suggesting that smoking cessation is associated with normalisation of peptide concentrations.

Predictive value of rectal bleeding for distal colonic neoplastic lesions in a screened population

The aim of this study was to determine the diagnostic value of rectal bleeding for distal colorectal cancer (CRC), or large (> or =10 mm) adenomas among an average-risk population. A cross-sectional survey was conducted among individuals aged 55-64 years, who attended sigmoidoscopy (FS) screening in the context of a multicentre randomised trial of FS screening for CRC. Sensitivity, specificity and positive predictive value (PPV) of rectal bleeding for large distal adenomas or CRC were calculated. Rectal bleeding was reported by 8.8% of 8507 patients examined (15% of those with large adenomas and 29% of those with CRC). The risk of CRC was increased when bleeding was associated with an altered bowel habit: odds ratio (OR)=10.42; 95% Confidence Interval (CI): 4.08-26.59; the corresponding OR for isolated bleeding was 5.29 (95% CI: 2.28-12.30). Rectal bleeding carries an increased risk of distal neoplastic lesions. However, most lesions are detected among asymptomatic subjects. This finding suggests that screening represents the optimal strategy to detect CRC or large adenomas in the distal colon in the targeted age range.

Costs of flexible sigmoidoscopy screening for colorectal cancer in the United Kingdom

OBJECTIVES

Colorectal cancer is one of the most commonly occurring cancers in industrialized countries, yet appears to be amenable to screening. Amongst the many possible protocols is once-only screening by means of flexible sigmoidoscopy. This protocol is currently being investigated in a UK multicenter trial and the study provides estimates of the expected resource costs.

METHODS

The direct health care costs of sigmoidoscopy and of all subsequent procedures were estimated from an audit of resource use of approximately 40,000 patients at thirteen centers. Patient-borne costs were estimated from the results of surveys conducted at twelve of these centers.

RESULTS

The health service costs of a flexible sigmoidoscopy was estimated at pounds 56. The total costs of screening (including private costs) averaged pounds 82 per person screened, although costs varied by center. The total health service costs of screening and subsequent management averaged approximately pounds 91 per person screened, again with variations between centers.

CONCLUSIONS

Even within a strict trial protocol, intercenter variation in costs can be detected, ascribable to variability in local management practices, local yield, and local patient-borne costs. Other recent estimates of flexible sigmoidoscopy costs vary widely. As these costs form the basis of technology assessment simulation models which, in turn, inform policy obtaining realistic cost estimates within the appropriate health care setting is of paramount importance.

Effect of hysterectomy status on polyp detection rates at screening flexible sigmoidoscopy

BACKGROUND

Flexible sigmoidoscopy with polypectomy reduces the incidence of colorectal cancer by removal of premalignant lesions. Factors that reduce the area examined by flexible sigmoidoscopy may reduce its benefit. The aim of this study was to determine whether hysterectomy affects completion and polyp detection rates at flexible sigmoidoscopy.

METHODS

Within the setting of a multicenter, prospective, controlled trial of screening flexible sigmoidoscopy, patient and examination variables were compared by appropriate statistical methods for women between the ages of 55 and 64 years with and without a history of a hysterectomy.

RESULTS

One quarter of women participants had undergone a hysterectomy. These women were more likely to have incomplete examinations (risk ratio [RR] of incomplete examination, 1.53; 95% CI [1.4, 1.6]). Flexible sigmoidoscopy was more difficult (p < 0.001), more painful (p < 0.001), and less extensive (46 cm vs. 48 cm insertion on average; p < 0.0001) in women who had undergone a hysterectomy. There was a significant trend toward lower relative detection rates of polyps and adenomas at more proximal sites (rectum, sigmoid colon, and proximal to sigmoid; respectively, p = 0.008, p = 0.009) in this group.

CONCLUSIONS

Women who have undergone a hysterectomy have less extensive flexible sigmoidoscopy examinations, which are more difficult and more painful, than women without a hysterectomy. Hysterectomy is associated with a reduction in polyp detection rate in the sigmoid colon. This modality of screening may be less effective in women who have undergone a hysterectomy.

An ancestral Ashkenazi haplotype at the HMPS/CRAC1 locus on 15q13-q14 is associated with hereditary mixed polyposis syndrome

The putative locus for hereditary mixed polyposis syndrome (HMPS) in a large family of Ashkenazi descent (SM96) was previously reported to map to chromosome sub-bands 6q16-q21. However, new clinical data, together with molecular data from additional family members, have shown 6q linkage to be incorrect. A high-density genomewide screen for the HMPS gene was therefore performed on SM96, using stringent criteria for assignment of affection status to minimize phenocopy rates. Significant evidence of linkage was found only on a region on chromosome 15q13-q14. Since this region encompassed CRAC1, a locus involved in inherited susceptibility to colorectal adenomas and carcinomas in another Ashkenazi family (SM1311), we determined whether HMPS and CRAC1 might be the same. We found that affected individuals from both families shared a haplotype between D15S1031 and D15S118; the haplotype was rare in the general Ashkenazi population. A third informative family, SM2952, showed linkage of disease to HMPS/CRAC1 and shared the putative ancestral haplotype, as did a further two families, SMU and RF. Although there are probably multiple causes of the multiple colorectal adenoma and cancer phenotype in Ashkenazim, an important one is the HMPS/CRAC1 locus on 15q13-q14.

Baseline findings of the Italian multicenter randomized controlled trial of "once-only sigmoidoscopy"--SCORE

BACKGROUND

A single sigmoidoscopy examination at around age 60 years has been proposed as a cost-effective strategy to prevent colorectal cancer. A multicenter randomized controlled trial, the SCORE trial, is in progress in Italy to estimate the impact of this strategy on colorectal cancer incidence and mortality and the duration of the protective effect. We present the baseline screening outcomes.

METHODS

A questionnaire was mailed to a random sample of 236 568 people aged 55-64 years to assess their eligibility for and interest in screening. Those reporting a history of colorectal cancer, adenomas, inflammatory bowel disease, recent colorectal endoscopy, or two first-degree relatives with colorectal cancer were excluded. Eligible, interested respondents were assigned randomly to the control group (no further contact) or the intervention group (invitation to undergo sigmoidoscopy). Screenees with colorectal cancer, polyps larger than 5 mm, three or more adenomas, adenomas 5 mm or smaller with a villous component of more than 20%, or severe dysplasia were referred for colonoscopy.

RESULTS

Of the 56 532 respondents (23.9% of those invited), 34 292 were enrolled and 17 148 were assigned to the screening group. Of those, 9999 attended and 9911 were actually examined by sigmoidoscopy. Distal adenomas were detected in 1070 subjects (10.8%). Proximal adenomas were detected in 116 of 747 (15.5%) subjects without cancer at sigmoidoscopy who then underwent colonoscopy. A total of 54 subjects was found to have colorectal cancer, a rate of 5.4 per 1000 (54% of which were Dukes' A). The procedures were relatively safe, with two perforations (one in 9911 sigmoidoscopy exams and one in 775 colonoscopies) and one hemorrhage requiring hospitalization after polypectomy during colonoscopy. The pain associated with sigmoidoscopy was described as mild or less than expected by 83.3% of the screenees.

CONCLUSION

Sigmoidoscopy screening is generally acceptable to recipients and safe. The high yield of advanced adenomas is consistent with the projected impact of sigmoidoscopy screening on colorectal cancer incidence.

Total colonic dye-spray increases the detection of diminutive adenomas during routine colonoscopy: a randomized controlled trial

BACKGROUND

Small adenomas may be missed during colonoscopy, but chromoscopy has been reported to enhance detection. The aim of this randomized-controlled trial was to determine the effect of total colonic dye spray on adenoma detection during routine colonoscopy.

METHODS

Consecutive outpatients undergoing routine colonoscopy were randomized to a dye-spray group (0.1% indigo carmine used to coat the entire colon during withdrawal from the cecum) or control group (no dye).

RESULTS

Two hundred fifty-nine patients were randomized, 124 to the dye-spray and 135 to the control group; demographics, indication for colonoscopy, and quality of the preparation were similar between the groups. Extubation from the cecum took a median of 9:05 minutes (range: 2:48-24:44 min) in the dye-spray group versus 4:52 minutes (range: 1:42-15:21 min) in the control group (p < 0.0001). The proportion of patients with at least 1 adenoma and the total number of adenomas were not different between groups. However, in the dye-spray group significantly more diminutive adenomas (<5 mm) were detected proximal to the sigmoid colon (p = 0.026) and more patients were identified with 3 or more adenomas (p = 0.002). More non-neoplastic polyps were detected throughout the colon in the dye-spray group (p = 0.003). There were no complications.

CONCLUSIONS

Dye-spray increases the detection of small adenomas in the proximal colon and patients with multiple adenomas, but long-term outcomes should be studied to determine the clinical value of these findings.

Single flexible sigmoidoscopy screening to prevent colorectal cancer: baseline findings of a UK multicentre randomised trial

BACKGROUND

This randomised controlled trial is examining the hypothesis that a single flexible sigmoidoscopy screening offered at around age 60 years can lower the incidence and mortality of colorectal cancer. We report here on acceptability, safety, feasibility, and yield.

METHODS

Men and women aged 55-64 years, in 14 UK centres, who responded to a mailed questionnaire that they would attend for flexible sigmoidoscopy screening if invited, were randomly assigned screening or control (ratio one to two). The control group was not contacted. Small polyps were removed during screening, and colonoscopy was undertaken if high-risk polyps (three or more adenomas, size 1 cm or greater, villous, severely dysplastic, or malignant) were found.

FINDINGS

Of 354,262 people asked about their interest in having flexible sigmoidoscopy screening, 194,726 (55%) responded positively, and 170,432 eligible individuals were randomised. Attendance among those assigned screening was 71% (40,674 of 57,254). 2131 (5%) were classified as high-risk and referred for colonoscopy; 38,525 with no polyps or only low-risk polyps detected were discharged. Distal adenomas were detected in 4931 (12.1%) and distal cancer in 131 (0.3%). Proximal adenomas were detected in 386 (18.8% of those undergoing colonoscopy) and proximal cancer in nine cases (0.4%). 62% of cancers were Dukes' stage A or locally excised. There was one perforation after flexible sigmoidoscopy and four after colonoscopy. An average of 48 people were screened, and two or three colonoscopy referrals generated, per centre each week. Interpretation Our flexible sigmoidoscopy screening regimen is acceptable, feasible, and safe. The prevalence of neoplasia is high, and colonoscopy referral rates of 5% are acceptable.

Design of a multicentre randomised trial to evaluate flexible sigmoidoscopy in colorectal cancer screening

A randomised, controlled trial in progress in 14 United Kingdom and six Italian centres is evaluating screening for colorectal cancer using a single flexible sigmoidoscopy (FS) at around the age of 60 with removal during FS of all small adenomas, and colonoscopy for "high risk" polyps. The regimen aims to ensure that 95% of people (with either no polyps or only low risk polyps) complete the entire screening process in a single visit. This paper describes the rationale and design of the trial. Participants were patients aged between 55 and 64 on the lists of designated general practitioners (GPs) who were not excluded by their GP. A two stage recruitment procedure was employed to raise compliance rates in the intervention group. Potentially eligible persons were sent an "interest in screening" questionnaire; those who responded positively were randomised to the intervention or control groups. The trial is sufficiently large to estimate within narrow confidence intervals the magnitude of benefit and the duration of effect and optimum age for a single screen. It also examines the feasibility and acceptability of the screening regimen, and will identify training and quality assurance issues. Recruitment and screening are now complete and all baseline data have been collected. The first analysis of the effect on colorectal cancer incidence and mortality rates and suitability for a national screening programme can be expected in 2004.

Rectal retroflexion: an essential part of lower gastrointestinal endoscopic examination

PURPOSE

Retroflexion of the endoscope during rectal examination may increase diagnostic yield but is not routinely performed because of concerns about safety and a lack of appreciation of its importance. The purpose of this study was to examine the yield, safety, and tolerance of endoscopic rectal retroflexion.

METHODS

Prospective cohorts of subjects undergoing unsedated screening flexible sigmoidoscopy were examined with and without routine retroflexion. Pain scores were recorded.

RESULTS

A total of 526 subjects (mean age 60 (range, 55-66) years) underwent flexible sigmoidoscopy in the first period when the endoscope was not routinely retroflexed. Of these, 480 (mean age 60 (range, 55-66) years) were subsequently examined with routine retroflexion. Retroflexion was impossible in 17 subjects (3.5 percent) because of discomfort. In the second group, 12 subjects (2.5 percent) had polyps in the lower rectum seen only on retroflexion. Of these, eight had metaplastic and four had adenomatous polyps (3 tubular <5 mm, 1 tubulovillous 15 mm). There was no difference in mean pain scores between the groups (no retroflexion = 2.13, retroflexion = 2.18).

CONCLUSION

With an adenoma pick-up rate of 8 to 12 percent for screening flexible sigmoidoscopy, retroflexion increases adenoma detection by approximately 1 percent without adverse effects and should be an integral part of flexible sigmoidoscopy.

Microsatellite instability: application in hereditary non-polyposis colorectal cancer

Colorectal cancer (CRC) is a significant cause of mortality in Western populations. About 15% of CRC patients report a family history of the disease. Studies on individuals with a genetic predisposition to CRC have been responsible for significant advances in the understanding of this disease. Thus, although developments in molecular biology have been mainly restricted to a minority of individuals with a hereditary background, information obtained from this group may affect the diagnosis and therapy of sporadic CRCs as well. Deficiency in the DNA mismatch repair (MMR) system results in microsatellite instability (MSI). Individuals from hereditary non-polyposis colorectal cancer (HNPCC) kindreds with germline mutations in genes involved in MMR may benefit from clinical screening programs. The higher frequency of MSI in HNPCC than in sporadic tumours suggests that involvement of MMR genes in sporadic adenomas may be uncommon. Consequently

High-risk colorectal adenomas and serum insulin-like growth factors

BACKGROUND

This study investigated the hypothesis that circulating levels of insulin-like growth factor (IGF) I and its main binding protein (IGFBP-3) predict for the presence of colorectal adenomas, surrogate markers of colorectal cancer risk.

METHODS

Within the Flexi-Scope Trial (healthy volunteers aged 55-64 years), at one study centre, IGF-I and IGFBP-3 levels in serum samples collected prospectively from 442 attendants were measured. Of these, 100 individuals underwent a complete screening colonoscopy. There were 47 normal examinations, while in 11 examinations low-risk adenomas and in 42 examinations high-risk adenomas were identified. Estimates of relative risk (RR) for the adenomatous stages were calculated by means of unconditional logistic regression, adjusting for known risk factors.

RESULTS

Mean serum IGF-I and IGFBP-3 levels were similar in individuals with a normal colonoscopy finding and in those with low-risk adenomas. By contrast, the mean(s.d.) serum IGF-I level was increased (190(53) versus 169(54) microg/l; P = 0.06) and the serum IGFBP-3 concentration was significantly decreased (3.22(0.60) versus 3.47(0.62) mg/l; P = 0.05) in individuals with high-risk adenomas compared with levels in those with normal colonoscopy and low-risk adenomas combined. Levels were unaffected by removal of the adenomas. With high-risk adenoma as the dependent factor, regression models demonstrated a significant positive association with IGF-I after controlling for IGFBP-3 (RR per one standard deviation (1s.d.) change 4.39 (95 per cent confidence interval (c.i.) 1.31-14.7); P = 0.02) and, independently, an inverse association with IGFBP-3 after adjustment for IGF-I (RR per 1s.d. change 0.41 (95 per cent c.i. 0. 20-0.82); P = 0.01).

CONCLUSION

These findings suggest that circulating IGF-I and IGFBP-3 levels are related to future colorectal cancer risk and, specifically, may predict adenoma progression.

Circulating insulin-like growth factor II and colorectal adenomas

Circulating insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) may be risk factors for the development of colorectal cancer. On the other hand, IGF-II and IGFBP-2 are overexpressed in colorectal carcinomas. These contrasting backgrounds led us to investigate the relationship between serum IGF-I, IGF-II, IGFBP-2, and IGFBP-3 and the presence of colorectal adenomas, known precursors of colorectal carcinoma, in 345 volunteers attending a screening flexible sigmoidoscopy trial (entry criteria: healthy, aged 55-64 yr). The most striking finding was an elevated mean serum IGF-II in individuals with adenomas (n = 52) compared with controls (mean difference, 139 ng/mL; 95% confidence intervals, 82, 196; P < 0.0001). Logistic regression adjusting for confounding factors confirmed the significant association between IGF-II and adenoma occurrence (P < 0.0001) and revealed an additional positive association with serum IGFBP-2 (P < 0.0001). However, there was no association found between either serum IGF-I and/or IGFBP-3 and the presence of adenomas. Additionally, in 31 individuals with adenomas in whom levels were determined pre- and postpolypectomy, there was a significant fall in mean IGF-II (P < 0.001) and IGFBP-2 (P < 0.001) after adenoma removal, but no difference in IGF-II and IGFBP-2 concentrations between repeated samples in 20 individuals without adenomas. Immunohistochemical studies demonstrated IGF-II expression in 83% of all adenomas, which contrasted with absent expression in normal colonic expression and hyperplastic polyps. This study has shown for the first time that serum IGF-II may be a tumor marker in individuals with colorectal adenomas. Further studies are needed to validate these relationships in larger populations, including individuals undergoing colonoscopy.

Single blind, randomised trial of efficacy and acceptability of oral picolax versus self administered phosphate enema in bowel preparation for flexible sigmoidoscopy screening

OBJECTIVE

To compare the acceptability and efficacy of two methods of self administered bowel preparation for flexible sigmoidoscopy screening: a single phosphate enema and a single sachet of Picolax.

DESIGN

Single blind, randomised trial.

SETTING

Endoscopy units of two general hospitals.

PARTICIPANTS

1442 men and women aged 55-64 years who had agreed to be screened by flexible sigmoidoscopy. MAIN OUTCOME MESURESs: Attendance rates, compliance with allocated preparations, adverse effects, quality of bowel preparation, procedure time, and yield of neoplasia.

RESULTS

Compliance with the enema was higher than with the Picolax (608 (84%) v 566 (79%); difference 6%, 95% confidence interval 2% to 10%). Almost half of those who refused Picolax used an enema at home. Wind, incontinence, and sleep disturbance were more frequent in the Picolax group than the enema group; bottom soreness was more frequent in the enema group. Around 30% (187) found the diet restriction required by Picolax difficult; 78% (471) found the enema easy to administer. The quality of preparation was better with the enema; the proportion of procedures complete to the descending colon was greater and the mean duration of the procedure was shorter. There was no significant difference in polyp detection rates.

CONCLUSION

A single phosphate enema self administered around one hour before leaving home is a more acceptable and effective method of preparing the distal bowel for flexible sigmoidoscopy than Picolax.

Inhaled patient-administered nitrous oxide/oxygen mixture does not impair driving ability when used as analgesia during screening flexible sigmoidoscopy

BACKGROUND

Entonox (nitrous oxide/oxygen mixture) has an analgesic effect, but its use is currently contraindicated in patients who plan to drive after its administration. We assessed the effect on driving ability of Entonox used as analgesia in patients undergoing screening flexible sigmoidoscopy.

METHODS

Forty men and 40 women scheduled for screening flexible sigmoidoscopy who had not driven to the examination site were recruited together with a matched control subject from the same list. Before the examination complex motor skills were assessed in both groups using an adaptive tracking task, previously demonstrated to be the most sensitive test for detecting impairment of driving ability due to drugs. During the examination Entonox analgesia was available to the study group only, and after the screening examination complex motor function was retested on the same computer.

RESULTS

Both groups improved their computer score on repeat testing, by 0.53 (range -1.9 to 4.6) in the study group and by 0.44 (range -0.6 to 2.5) in the control group.

CONCLUSIONS

These data strongly support the view that Entonox analgesia does not impair driving ability. In the context of screening flexible sigmoidoscopy its use may lead to an increase in compliance.