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

Long-term effects of once-only flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: 21-year follow-up of the UK Flexible Sigmoidoscopy Screening randomised controlled trial

BACKGROUND

Flexible sigmoidoscopy screening reduces colorectal cancer incidence and mortality; however, uncertainty exists about the duration of protection and differences by sex and age. We assessed effects of once-only flexible sigmoidoscopy screening after 21 years' follow-up.

METHODS

The UK Flexible Sigmoidoscopy Screening Trial is a multicentre randomised controlled trial that recruited men and women aged 55-64 years from general practices serving 14 hospitals. Among participants indicating that they would attend flexible sigmoidoscopy screening if invited, randomisation (2:1) to the control (no further contact) or intervention (invited to once-only flexible sigmoidoscopy screening) group was performed centrally in blocks of 12, stratified by centre, general practice, and household type. Masking of intervention was infeasible. Primary outcomes were colorectal cancer incidence and mortality. The Kaplan-Meier method estimated cumulative incidence. Primary analyses estimated intention-to-treat hazard ratios (HRs) and risk differences, overall and stratified by subsite, sex, and age. The trial is registered with ISRCTN, number 28352761.

FINDINGS

Among participants recruited between Nov 14, 1994, and March 30, 1999, 170 432 were eligible and 113 195 were randomly assigned to the control group and 57 237 were randomly assigned to the intervention group. 406 participants were excluded from analyses (268 in the control group and 138 in the intervention group), leaving 112 927 participants in the control group (55 336 [49%] men and 57 591 [51%] women) and 57 099 in the intervention group (27 966 [49%] men and 29 103 [51%] women). Of participants who were invited to be screened, 40 624 (71%) attended screening. Median follow-up was 21·3 years (IQR 18·0-22·2). In the invited-to-screening group, colorectal cancer incidence was reduced compared with the control group (1631 vs 4201 cases; cumulative incidence at 21 years was 3·18% [95% CI 3·03 to 3·34] vs 4·16% [4·04 to 4·29]; HR 0·76 [95% CI 0·72 to 0·81]) with 47 fewer cases per 100 000 person-years (95% CI -56 to -37). Colorectal cancer mortality was also reduced in the invited-to-screening group compared with the control group (502 vs 1329 deaths; cumulative incidence at 21 years was 0·97% [0·88 to 1·06] vs 1·33% [1·26 to 1·40]; HR 0·75 [0·67 to 0·83]) with 16 fewer deaths per 100 000 person-years (-21 to -11). Effects were particularly evident in the distal colorectum (726 incident cancer cases in the invited-to-screening group vs 2434 cases in the control group; HR 0·59 [0·54 to 0·64]; 47 fewer cases per 100 000 person-years [-54 to -41]; 196 cancer deaths in the invited-to-screening group vs 708 deaths in the control group; HR 0·55 [0·47 to 0·64]; 15 fewer deaths per 100 000 person-years [-19 to -12]) and not the proximal colon (871 incident cancer cases in the invited-to-screening group vs 1749 cases in the control group; HR 0·98 [0·91 to 1·07]; one fewer case per 100 000 person-years [-8 to 5]; 277 cancer deaths in the invited-to-screening group vs 547 deaths in the control group; HR 1·00 [0·86 to 1·15]; zero fewer deaths per 100 000 person-years [-4 to 4]). The HR for colorectal cancer incidence was lower in men (0·70 [0·65-0·76]) than women (0·86 [0·79 to 0·93]; pinteraction=0·0007) but there was no difference by age.

INTERPRETATION

We show that once-only flexible sigmoidoscopy screening reduces colorectal cancer incidence and mortality for two decades and provide important data to inform colorectal cancer screening guidelines.

FUNDING

National Institute for Health and Care Research Health Technology Assessment Programme and the Medical Research Council.

The clinical effectiveness of different surveillance strategies to prevent colorectal cancer in people with intermediate-grade colorectal adenomas: a retrospective cohort analysis, and psychological and economic evaluations

BACKGROUND

The UK guideline recommends 3-yearly surveillance for patients with intermediate-risk (IR) adenomas. No study has examined whether or not this group has heterogeneity in surveillance needs.

OBJECTIVES

To examine the effect of surveillance on colorectal cancer (CRC) incidence; assess heterogeneity in risk; and identify the optimum frequency of surveillance, the psychological impact of surveillance, and the cost-effectiveness of alternative follow-up strategies.

DESIGN

Retrospective multicentre cohort study.

SETTING

Routine endoscopy and pathology data from 17 UK hospitals (n = 11,944), and a screening data set comprising three pooled cohorts (n = 2352), followed up using cancer registries.

SUBJECTS

Patients with IR adenoma(s) (three or four small adenomas or one or two large adenomas).

PRIMARY OUTCOMES

Advanced adenoma (AA) and CRC detected at follow-up visits, and CRC incidence after baseline and first follow-up.

METHODS

The effects of surveillance on long-term CRC incidence and of interval length on findings at follow-up were examined using proportional hazards and logistic regression, adjusting for patient, procedural and polyp characteristics. Lower-intermediate-risk (LIR) subgroups and higher-intermediate-risk (HIR) subgroups were defined, based on predictors of CRC risk. A model-based cost-utility analysis compared 13 surveillance strategies. Between-group analyses of variance were used to test for differences in bowel cancer worry between screening outcome groups (n = 35,700). A limitation of using routine hospital data is the potential for missed examinations and underestimation of the effect of interval and surveillance.

RESULTS

In the hospital data set, 168 CRCs occurred during 81,442 person-years (pys) of follow-up [206 per 100,000 pys, 95% confidence interval (CI) 177 to 240 pys]. One surveillance significantly lowered CRC incidence, both overall [hazard ratio (HR) 0.51, 95% CI 0.34 to 0.77] and in the HIR subgroup (n = 9265; HR 0.50, 95% CI 0.34 to 0.76). In the LIR subgroup (n = 2679) the benefit of surveillance was less clear (HR 0.62, 95% CI 0.16 to 2.43). Additional surveillance lowered CRC risk in the HIR subgroup by a further 15% (HR 0.36, 95% CI 0.20 to 0.62). The odds of detecting AA and CRC at first follow-up (FUV1) increased by 18% [odds ratio (OR) 1.18, 95% CI 1.12 to 1.24] and 32% (OR 1.32, 95% CI 1.20 to 1.46) per year increase in interval, respectively, and the odds of advanced neoplasia at second follow-up increased by 22% (OR 1.22, 95% CI 1.09 to 1.36), after adjustment. Detection rates of AA and CRC remained below 10% and 1%, respectively, with intervals to 3 years. In the screening data set, 32 CRCs occurred during 25,745 pys of follow-up (124 per 100,000 pys, 95% CI 88 to 176 pys). One follow-up conferred a significant 73% reduction in CRC incidence (HR 0.27, 95% CI 0.10 to 0.71). Owing to the small number of end points in this data set, no other outcome was significant. Although post-screening bowel cancer worry was higher in people who were offered surveillance, worry was due to polyp detection rather than surveillance. The economic evaluation, using data from the hospital data set, suggested that 3-yearly colonoscopic surveillance without an age cut-off would produce the greatest health gain.

CONCLUSIONS

A single surveillance benefited all IR patients by lowering their CRC risk. We identified a higher-risk subgroup that benefited from further surveillance, and a lower-risk subgroup that may require only one follow-up. A surveillance interval of 3 years seems suitable for most IR patients. These findings should be validated in other studies to confirm whether or not one surveillance visit provides adequate protection for the lower-risk subgroup of intermediate-risk patients.

STUDY REGISTRATION

Current Controlled Trials ISRCTN15213649.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Long term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up: the UK Flexible Sigmoidoscopy Screening randomised controlled trial

BACKGROUND

Colorectal cancer is the third most common cancer worldwide. Previous analyses have only reported follow-up after flexible sigmoidoscopy for a maximum of 12 years. We aimed to examine colorectal cancer incidence and mortality after a single flexible sigmoidoscopy screening and 17 years of follow-up.

METHODS

In this multicentre randomised trial (UK Flexible Sigmoidoscopy Screening Trial), done between Nov 14, 1994, and March 30, 1999, 170 432 eligible men and women, who had indicated on a previous questionnaire that they would probably attend screening if invited, were randomly assigned (1:2) to an intervention group (offered flexible sigmoidoscopy screening) or a control group (not contacted). Randomisation was done centrally in blocks of 12, and stratified by trial centre, general practice, and household type. The nature of the intervention did not allow the staff to be masked to arm of the trial; however, randomisation was done in batches so that the control group and participants not yet randomised were unaware of their allocation status. The primary outcomes were incidence and mortality of colorectal cancer. Hazard ratios (HRs) and 95% CIs for colorectal cancer incidence and mortality were estimated for intention-to-treat and per-protocol analyses. The trial is registered with ISRCTN, number 28352761.

FINDINGS

Our cohort analysis included 170 034 people: 112 936 in the control group and 57 098 in the intervention group, 40 621 (71%) of whom were screened and 16 477 (29%) were not screened. During screening and a median of 17·1 years' follow-up, colorectal cancer was diagnosed in 1230 individuals in the intervention group and 3253 in the control group, and 353 individuals in the intervention group versus 996 individuals in the control group died from colorectal cancer. In intention-to-treat analyses, colorectal cancer incidence was reduced by 26% (HR 0·74 [95% CI 0·70-0·80]; p<0·0001) in the intervention group versus the control group and colorectal cancer mortality was reduced by 30% (0·70 [0·62-0·79]; p<0·0001) in the intervention group versus the control group. In per-protocol analyses, adjusted for non-compliance, colorectal cancer incidence and mortality were 35% (HR 0·65 [95% CI 0·59-0·71]) and 41% (0·59 [0·49-0·70]) lower in the screened group.

INTERPRETATION

A single flexible sigmoidoscopy continues to provide substantial protection from colorectal cancer diagnosis and death, with protection lasting at least 17 years.

FUNDING

National Institute for Health Research Efficacy and Mechanism Evaluation.

Marriage and cancer prevention: Does marital status and inviting both spouses together influence colorectal cancer screening participation?

Objectives

This study examined the influence of marital status and inviting both partners together on participation in colorectal cancer screening.

Setting

Data were from a subset of participants from the UK Flexible Sigmoidoscopy Trial (1996–1999).

Methods

Marital status was self-reported, and co-invitation of partner was obtained from the trial database. Screening intentions were assessed in 16,527 adults aged 55–64 years. Attendance was recorded in the 4130 respondents who were subsequently invited.

Results

Multivariate analyses, controlling for age and educational level, indicate that married (or cohabiting) people have more positive intentions (odds ratio [OR] 1.26; 95% confidence interval [CI] 1.14–1.38) and higher attendance rates at screening (OR = 1.23; 95% CI 1.04–1.45) than non-married people. After adjusting for the marriage effect, inviting partners together (co-invitation) significantly increased screening intentions among women (OR = 1.17; 95% CI 1.04–1.31) but not men (OR = 0.97; 95% CI 0.85–1.10). Co-invitation significantly increased attendance at screening in both genders (OR = 1.34; 95% CI 1.14–1.58).

Conclusions

In this age group, married adults are more likely to participate in colorectal cancer screening than the non-married, and inviting both members of a couple together further increases screening uptake. The positive effect of marriage was as strong for women as men.

Cancer fear: facilitator and deterrent to participation in colorectal cancer screening

BACKGROUND

Cancer fear has been associated with higher and lower screening uptake across different studies, possibly because different aspects of cancer fear have different effects on intentions versus behavior. The present study examined associations of three aspects of cancer fear with intention and uptake of endoscopic screening for colorectal cancer.

METHODS

A subsample of UK Flexible Sigmoidoscopy (FS) Trial participants received a baseline questionnaire that included three cancer fear items from a standard measure asking if: (i) cancer was feared more than other diseases, (ii) cancer worry was experienced frequently, and (iii) thoughts about cancer caused discomfort. Screening intention was assessed by asking participants whether, if invited, they would accept an invitation for FS screening. Positive responders were randomized to be invited or not in a 1:2 ratio. The behavioral outcome was clinic-recorded uptake. Control variables were age, gender, ethnicity, education, and marital status.

RESULTS

The questionnaire return rate was 60% (7,971/13,351). The majority (82%) intended to attend screening; 1,920 were randomized to receive an invitation, and 71% attended. Fearing cancer more than other diseases (OR = 2.32, P < 0.01) and worrying a lot about cancer (OR = 2.34, P < 0.01) increased intentions to attend screening, but not uptake. Finding thoughts about cancer uncomfortable did not influence intention, but predicted lower uptake (OR = 0.72, P < 0.01).

CONCLUSIONS

Different aspects of cancer fear have different effects on the decision and action processes leading to screening participation.

IMPACT

Knowledge of the different behavioral effects of cancer fear may aid the design of effective public health messages.

Blood-based testing for colorectal cancer screening

Colorectal cancer (CRC) is the third most common non-skin cancer diagnosed in men and women in the USA and worldwide. While it has been clearly established that screening for CRC, using a variety of methods, is cost effective and has a significant impact on overall survival, screening rates have proven to be sub-optimal. It has been long conjectured that a simple blood-based test, with a specimen drawn at a routine doctor's office visit, would encourage those individuals who have refused or ignored screening recommendations to undergo screening. This article reviews the currently available blood-based screening tests for CRC, including the ColonSentry™ messenger RNA (mRNA) expression panel and the SEPT9 methylated DNA test, and explores newer biomarkers that are near clinical implementation. Also discussed are additional applications for blood-based CRC testing, such as assessing prognosis, disease surveillance, and expansion of screening tests to high-risk populations, such as the estimated 1.4 million individuals in the USA with inflammatory bowel disease.

The structure and demographic correlates of cancer fear

Background

Cancer is often described as the ‘number one’ health fear, but little is known about whether this affects quality of life by translating into high levels of worry or distress in everyday life, or which population groups are most affected. This study examined the prevalence of three components of cancer fear in a large community sample in the UK and explored associations with demographic characteristics.

Methods

Questions on cancer fear were included in a survey mailed to a community sample of adults (n = 13,351; 55–64 years). Three items from a standard measure of cancer fear assessed: i) whether cancer was feared more than other diseases, ii) whether thinking about cancer caused discomfort, and iii) whether cancer worry was experienced frequently. Gender, marital status, education, and ethnicity were assessed with simple questions. Anxiety was assessed with the brief STAI and a standard measure of self-rated health was included.

Results

Questionnaire return rate was 60% (7,971/13,351). The majority of respondents agreed or strongly agreed that they feared cancer more than other diseases (59%), and felt uncomfortable thinking about it (52%), and a quarter (25%) worried a lot about cancer. All items were significantly inter-correlated (r = .35 to .42, p’s < .001), and correlated with general anxiety (r = .16 to .28, p’s < .001) and self-rated health (r = -.07 to -.16, p’s < .001). In multivariable analyses including anxiety and general health, all cancer fear indicators were significantly higher in women (ORs between 1.15 and 1.48), respondents with lower education (ORs between 1.40 and 1.66), and those with higher general anxiety (ORs between 1.50 and 2.11). Ethnic minority respondents (n = 285; 4.4%) reported more worry (OR: 1.85).

Conclusions

More than half of this older adult sample in the UK had cancer as greatest health fear and this was associated with feeling uncomfortable thinking about it and worrying more about it. Women and respondents with less education or from ethnic minority backgrounds were disproportionately affected by cancer fear. General anxiety and poor health were associated with cancer fear but did not explain the demographic differences.

Non- or full-laxative CT colonography vs. endoscopic tests for colorectal cancer screening: a randomised survey comparing public perceptions and intentions to undergo testing

Objectives

Compare public perceptions and intentions to undergo colorectal cancer screening tests following detailed information regarding CT colonography (CTC; after non-laxative preparation or full-laxative preparation), optical colonoscopy (OC) or flexible sigmoidoscopy (FS).

Methods

A total of 3,100 invitees approaching screening age (45-54 years) were randomly allocated to receive detailed information on a single test and asked to return a questionnaire. Outcomes included perceptions of preparation and test tolerability, health benefits, sensitivity and specificity, and intention to undergo the test.

Results

Six hundred three invitees responded with valid questionnaire data. Non-laxative preparation was rated more positively than enema or full-laxative preparations [effect size (r) = 0.13 to 0.54; p < 0.0005 to 0.036]; both forms of CTC and FS were rated more positively than OC in terms of test experience (r = 0.26 to 0.28; all p-values < 0.0005). Perceptions of health benefits, sensitivity and specificity (p = 0.250 to 0.901), and intention to undergo the test (p = 0.213) did not differ between tests (n = 144-155 for each test).

Conclusions

Despite non-laxative CTC being rated more favourably, this study did not find evidence that offering it would lead to substantially higher uptake than full-laxative CTC or other methods. However, this study was limited by a lower than anticipated response rate.

Key Points

• Improving uptake of colorectal cancer screening tests could improve health benefits

• Potential invitees rate CTC and flexible sigmoidoscopy more positively than colonoscopy

• Non-laxative bowel preparation is rated better than enema or full-laxative preparations

• These positive perceptions alone may not be sufficient to improve uptake

• Health benefits and accuracy are rated similarly for preventative screening tests

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-014-3187-9) contains supplementary material, which is available to authorized users.

Referral proformas improve compliance to national colorectal 2-week wait targets: does this affect cancer detection rates?

AIM

To facilitate implementation of National Institute for Health and Clinical Excellence (NICE) guidelines for urgent colorectal cancer referral, local cancer networks have promoted the use of standardized proformas in primary care. This clinical audit assessed use of the proforma within the Thames Valley Cancer Network (TVCN) to see whether increased proforma use was associated with higher compliance to NICE guidelines and higher cancer detection rates.

METHOD

All 2-week wait referrals for lower bowel cancer to the six Acute NHS Trusts in the TVCN received during the month of June 2010 were identified, anonymized and analysed in relation to colorectal cancer detection rates.

RESULTS

Of the 586 referrals audited, proforma usage varied significantly across the six Acute NHS Trusts from 18% to 96%. Referral letters from primary care had NICE compliance ranging from 30 to 50%. In those which received a referral protocol, 50-90% were NICE compliant. Proforma use was associated with higher cancer detection rates (P = 0.03).

CONCLUSION

These results have wide-ranging implications since they suggest that the adoption of a simple proforma in primary care can improve the effectiveness of referral for suspected cancer.

Coverage and performance of colorectal cancer screening with the faecal occult blood test in Finland

INTRODUCTION

Mortality from colorectal cancer has been shown to decrease by repeated screening using faecal occult blood (FOB) testing in randomized screening trials. This report presents coverage and performance of organized screening among the general population in Finland.

METHODS

In 2004-2007, people aged 60-69 years were randomized into biennial screening and control arms. The screening test was a guaiac-based FOB test (Hemoccult) with dietary restriction and three test cards for six consecutive samples. Test positives were referred for full colonoscopy. The programme was launched in 2004 and subsequently it expanded over regions and age-cohorts.

RESULTS

In 2007, the programme covered one-third of the target population and 74,592 people had been invited for screening, of them 26,866 for the second round. Uptakes for the first and second rounds, respectively, were 62% and 68% in men and 77% and 80% in women. The proportion of test positives increased from 2.4% to 2.9% from the first to the second round and the positive predictive value for cancers decreased from 7.5% to 4.3%.

CONCLUSIONS

By 2007, organized colorectal cancer screening covered one-third of the target population in Finland. Implementation of screening measured with response rate was successful and met the criteria for a public health programme, but performance in terms of positive predictive value needs monitoring.

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.

Polymorphisms in the adenomatous polyposis coli (APC) gene and advanced colorectal adenoma risk

While germline mutations in the adenomatous polyposis coli (APC) gene cause the hereditary colon cancer syndrome (familial adenomatous polyposis (FAP)), the role of common germline APC variants in sporadic adenomatous polyposis remains unclear. We studied the association of eight APC single nucleotide polymorphisms (SNPs), possibly associated with functional consequences, and previously identified gene-environment (dietary fat intake and hormone replacement therapy (HRT) use) interactions, in relation to advanced colorectal adenoma in 758 cases and 767 sex- and race-matched controls, randomly selected from the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Cases had at least one verified advanced adenoma of the distal colon; controls, a negative sigmoidoscopy. We did not observe an association between genotypes for any of the eight APC SNPs and advanced distal adenoma risk (P(global gene-based)=0.92). Frequencies of identified common haplotypes did not differ between cases and controls (P(global haplotype test)=0.97). However, the risk for advanced distal adenoma was threefold higher for one rare haplotype (cases: 2.7%; controls: 1.6%) (odds ratio (OR)=3.27; 95% confidence interval (CI)=1.08-9.88). The genetic association between D1822V and advanced distal adenoma was confined to persons consuming a high-fat diet (P(interaction)=0.03). Similar interactions were not observed with HRT use. In our large, nested case-control study of advanced distal adenoma and clinically verified adenoma-free controls, we observed no association between specific APC SNPs and advanced adenoma. Fat intake modified the APC D1822V-adenoma association, but further studies are warranted.

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.

Design issues in cancer screening trials

Randomised controlled trials avoid many of the potential biases associated with the evaluation of cancer screening. Nevertheless there are many issues concerning the design of such trials that require careful consideration and that will influence interpretation of the results. This article discusses issues related to recruitment and randomisation, which will affect the extent to which the population studied, is representative of the eventual target population of a screening programme. It addresses sample size considerations, the use of appropriate outcome measures and the timing of the intervention. Finally, issues related to ensuring appropriate analyses are discussed.

Colorectal cancer

Substantial progress has been made in colorectal cancer in the past decade. Screening, used to identify individuals at an early stage, has improved outcome. There is greater understanding of the genetic basis of inherited colorectal cancer and identification of patients at risk. Optimisation of surgery for patients with localised disease has had a major effect on survival at 5 years and 10 years. For rectal cancer, identification of patients at greatest risk of local failure is important in the selection of patients for preoperative chemoradiation, a strategy proven to improve outcomes in these patients. Stringent postoperative follow-up helps the early identification of potentially radically treatable oligometastatic disease and improves long-term survival. Treatment with adjuvant fluoropyrimidine for colon and rectal cancers further improves survival, more so in stage III than in stage II disease, and oxaliplatin-based combination chemotherapy is now routinely used for stage III disease, although efficacy must be carefully balanced against toxicity. In stage II disease, molecular markers such as microsatellite instability might help select patients for treatment. The integration of targeted treatments with conventional cytotoxic drugs has expanded the treatment of metastatic disease resulting in incremental survival gains. However, biomarker development is essential to aid selection of patients likely to respond to therapy, thereby rationalising treatments and improving outcomes.

Uptake of colorectal cancer screening: system, provider and individual factors and strategies to improve participation

Colorectal cancer (CRC) accounts for 9% of all new cancer cases worldwide and affects over 1 million people each year. Screening can reduce the mortality associated with the disease, yet participation rates are suboptimal. Compliers with CRC screening are less deprived; they have higher education than noncompliers and tend to be male, white and married. Likely reasons for nonparticipation encompass several 'modifiable' factors that could be targeted in interventions aimed at increasing participation rates. Successful intervention strategies include organizational changes, such as increasing access to fecal occult blood test (FOBT) kits, providing reminders to healthcare providers or users about screening opportunities, and educational strategies to improve awareness and attitudes towards CRC screening. Multifactor interventions that target more than one level of the screening process are likely to have larger effects. The biggest challenge for future research will be to reduce inequalities related to socio-economic position and ethnicity in the uptake of screening.

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.

Effect of rising chemotherapy costs on the cost savings of colorectal cancer screening

BACKGROUND

Although colorectal cancer screening is cost-effective, it requires a considerable net investment by governments or insurance companies. If screening was cost saving, governments and insurance companies might be more inclined to invest in colorectal cancer screening programs. We examined whether colorectal cancer screening would become cost saving with the widespread use of the newer, more expensive chemotherapies.

METHODS

We used the MISCAN-Colon microsimulation model to assess whether widespread use of new chemotherapies would affect the treatment savings of colorectal cancer screening in the general population. We considered three scenarios for chemotherapy use: the past, the present, and the near future. We assumed that survival improved and treatment costs for patients diagnosed with advanced stages of colorectal cancer increased over the scenarios. Screening strategies considered were annual guaiac fecal occult blood testing (FOBT), annual immunochemical FOBT, sigmoidoscopy every 5 years, colonoscopy every 10 years, and the combination of sigmoidoscopy every 5 years and annual guaiac FOBT. Analyses were conducted from the perspective of the health-care system for a cohort of 50-year-old individuals who were at average risk of colorectal cancer and were screened with 100% adherence from age 50 years to age 80 years and followed up until death.

RESULTS

Compared with no screening, the treatment savings from preventing advanced colorectal cancer and colorectal cancer deaths by screening more than doubled with the widespread use of new chemotherapies. The lifetime average treatment savings were larger than the lifetime average screening costs for screening with Hemoccult II, immunochemical FOBT, sigmoidoscopy, and the combination of sigmoidoscopy and Hemoccult II (average savings vs costs per individual in the population: Hemoccult II, $1398 vs $859; immunochemical FOBT, $1756 vs $1565; sigmoidoscopy, $1706 vs $1575; sigmoidoscopy and Hemoccult II $1931 vs $1878). Colonoscopy did not become cost saving, but the total net costs of this strategy decreased from $1317 to $296 per individual in the population.

CONCLUSIONS

With the increase in chemotherapy costs for advanced colorectal cancer, most colorectal cancer screening strategies have become cost saving. As a consequence, screening is a desirable approach not only to reduce colorectal cancer incidence and mortality but also to control the costs of colorectal cancer treatment.

Risk of colorectal cancer seven years after flexible sigmoidoscopy screening: randomised controlled trial

OBJECTIVE

To determine the risk of colorectal cancer after screening with flexible sigmoidoscopy.

DESIGN

Randomised controlled trial.

SETTING

Population based screening in two areas in Norway-city of Oslo and Telemark county (urban and mixed urban and rural populations).

PARTICIPANTS

55 736 men and women aged 55-64 years.

INTERVENTION

Once only flexible sigmoidoscopy screening with or without a single round of faecal occult blood testing (n=13 823) compared with no screening (n=41 913).

MAIN OUTCOME MEASURES

Planned end points were cumulative incidence and mortality of colorectal cancer after 5, 10, and 15 years. This first report from the study presents cumulative incidence after 7 years of follow-up and hazard ratio for mortality after 6 years.

RESULTS

No difference was found in the 7 year cumulative incidence of colorectal cancer between the screening and control groups (134.5 v 131.9 cases per 100 000 person years). In intention to screen analysis, a trend towards reduced colorectal cancer mortality was found (hazard ratio 0.73, 95% confidence interval 0.47 to 1.13, P=0.16). For attenders compared with controls, a statistically significant reduction in mortality was apparent for both total colorectal cancer (hazard ratio 0.41, 0.21 to 0.82, P=0.011) and rectosigmoidal cancer (0.24, 0.08 to 0.76, P=0.016).

CONCLUSIONS

A reduction in incidence of colorectal cancer with flexible sigmoidoscopy screening could not be shown after 7 years' follow-up. Mortality from colorectal cancer was not significantly reduced in the screening group but seemed to be lower for attenders, with a reduction of 59% for any location of colorectal cancer and 76% for rectosigmoidal cancer in per protocol analysis, an analysis prone to selection bias.

TRIAL REGISTRATION

Clinical trials NCT00119912.

Ethnic differences in participation in flexible sigmoidoscopy screening in the UK

OBJECTIVES

The aim of the study was to examine ethnic differences in participation in colorectal cancer screening by flexible sigmoidoscopy (FS). It assessed both intentions to be screened and actual screening uptake, and considered whether demographic, health and psychosocial factors mediated the ethnic differences. The setting of this study follows a subset of participants from the UK FS Trial.

METHODS

A postal questionnaire assessed ethnicity, demographic characteristics, health, attitudes to screening and FS screening intentions. Data on screening intentions were available for 17,333 adults aged 55-64 years (Sample 1). Screening uptake was recorded in a subsample of 4303 respondents who were subsequently randomized to receive an invitation to screening (Sample 2).

RESULTS

Screening intentions in Sample 1 were equally high across all the ethnic groups (>80% [13,724/17,042] reported they were interested). In contrast, attendance (Sample 2) was considerably lower among Asians (54% [43/79]) compared with White (69% [2843/4123]) or Black (80% [33/41]) respondents. Multivariate analysis showed that potential explanatory factors, including socioeconomic deprivation, poor health and fearful and fatalistic attitudes did not account for the lower screening attendance among Asians.

CONCLUSION

Further research is required to identify explanations for the gap between intentions and behaviour in UK Asians if any future FS screening programme is to be introduced equitably.

At what costs will screening with CT colonography be competitive? A cost-effectiveness approach

The costs of computed tomographic colonography (CTC) are not yet established for screening use. In our study, we estimated the threshold costs for which CTC screening would be a cost-effective alternative to colonoscopy for colorectal cancer (CRC) screening in the general population. We used the MISCAN-colon microsimulation model to estimate the costs and life-years gained of screening persons aged 50-80 years for 4 screening strategies: (i) optical colonoscopy; and CTC with referral to optical colonoscopy of (ii) any suspected polyp; (iii) a suspected polyp >or=6 mm and (iv) a suspected polyp >or=10 mm. For each of the 4 strategies, screen intervals of 5, 10, 15 and 20 years were considered. Subsequently, for each CTC strategy and interval, the threshold costs of CTC were calculated. We performed a sensitivity analysis to assess the effect of uncertain model parameters on the threshold costs. With equal costs ($662), optical colonoscopy dominated CTC screening. For CTC to gain similar life-years as colonoscopy screening every 10 years, it should be offered every 5 years with referral of polyps >or=6 mm. For this strategy to be as cost-effective as colonoscopy screening, the costs must not exceed $285 or 43% of colonoscopy costs (range in sensitivity analysis: 39-47%). With 25% higher adherence than colonoscopy, CTC threshold costs could be 71% of colonoscopy costs. Our estimate of 43% is considerably lower than previous estimates in literature, because previous studies only compared CTC screening to 10-yearly colonoscopy, where we compared to different intervals of colonoscopy screening.

A risk profile for advanced proximal neoplasms on diagnostic colonoscopy

The capacity for colonoscopy is limited and a method to prioritize patients for diagnostic colonoscopy is needed in health care centers. A retrospective cross-sectional cohort study was carried out in county and community endoscopy centers, which included 1,065 county and 279 community patients aged > or = 40 years undergoing diagnostic colonoscopy. We constructed a risk profile for proximal advanced neoplasms on diagnostic colonoscopy at the county center based on the size of the regression coefficients for independent risk factors from logistic regression. An advanced neoplasm was defined as one of size > or = 1 cm or containing villous histology, high-grade dysplasia, or cancer. In our county colonoscopy population (n = 929 after exclusions), the stepwise logistic regression analysis identified age > or = 60 years (adjusted odds ratio [AOR]: 2.60; 95% confidence interval [CI]:1.14, 6.14), iron deficiency anemia (AOR: 4.74; 95% CI: 2.07, 11.34), and an advanced neoplasm in the recto-sigmoid (AOR: 6.01; 95% CI: 2.02, 16.00) as the statistically significant predictors of an advanced proximal neoplasm. In the county population, the prevalence rates of an advanced proximal neoplasm and proximal high-grade dysplasia/cancer in the low-risk group were 0.71% (95% CI: 0.15, 2.05) and 0.24% (95% CI: 0.01, 1.31), respectively. Avoiding colonoscopy in this group would increase the capacity for colonoscopy by 46% in the higher risk groups. In a disparate community population (n = 237 after exclusions), this scoring system had a goodness-of-fit test showing high concordance (P = 0.51). This clinical profile stratified the risk for an advanced neoplasm proximal to the sigmoid in patients undergoing diagnostic colonoscopy. It identified a large subset of low-risk patients.

Predicting the impact of the screening programme for colorectal cancer in the UK

Objectives

Screening for colorectal cancer by biennial testing for faecal occult blood is being introduced in the UK from 2007. We examine the likely impact of the programme, in terms of reduced mortality, lives saved and changes in incidence, over the next 20 years.

Setting

Projections of incidence and mortality of colorectal cancer in England, and the policy that has been adopted for screening in England (biennial at ages 60–69 from 2007, then 60–74 in 2010).

Methods

The results are based on the output of a simulation model that has been used to examine cost-effectiveness of screening policy options, with two scenarios regarding compliance with screening; both assume that 20% of the population will never attend for screening, but attendance of those who do is modelled either as a random 60% or 80%, at each screening round.

Results

The decrease in mortality rates expected 20 years after introducing screening is 13–17% in men and 12–15% in women (depending on the attendance levels). The model predicts an initial rise in incidence, followed (after six to seven years) by a fall, so that there is little net change in the number of cases detected over a 20-year period.

Conclusion

Percentage changes in mortality seem modest, but the projected saving in terms of numbers of lives is not negligible – 1800–2400 per year by 2025 in England (equivalent numbers are 2200–2700 in all over the UK). Newer screening modalities may improve on these projected results.

Recruitment to multicentre trials--lessons from UKCTOCS: descriptive study

OBJECTIVE

To describe the factors that contributed to successful recruitment of more than 200,000 women to the UK Collaborative Trial of Ovarian Cancer Screening, one of the largest ever randomised controlled trials.

DESIGN

Descriptive study.

SETTING

13 NHS trusts in England, Wales, and Northern Ireland.

PARTICIPANTS

Postmenopausal women aged 50-74; exclusion criteria included ovarian malignancy, bilateral oophorectomy, increased risk of familial ovarian cancer, active non-ovarian malignancy, and participation in other ovarian cancer screening trials.

MAIN OUTCOME MEASURES

Achievement of target recruitment, acceptance rates of invitation, and recruitment rates.

RESULTS

The trial was set up in 13 centres with 27 adjoining local health authorities. The coordinating centre team was led by one of the senior investigators, who was closely involved in planning and day to day trial management. Of 1 243,282 women invited, 23.2% (288 955) replied that they were eligible and would like to participate. Of those sent appointments, 73.6% (205 090) attended for recruitment. The acceptance rate varied from 19% to 33% between trial centres. Measures to ensure target recruitment included named coordinating centre staff supporting and monitoring each centre, prompt identification and resolution of logistic problems, varying the volume of invitations by centre, using local non-attendance rates to determine the size of recruitment clinics, and organising large ad hoc clinics supported by coordinating centre staff. The trial randomised 202,638 women in 4.3 years.

CONCLUSIONS

Planning and trial management are as important as trial design and require equal attention from senior investigators. Successful recruitment needs constant monitoring by a committed proactive management team that is willing to explore individual solutions for different centres and use central resources to improve local recruitment. Automation of trial processes with web based trial management systems is crucial in large multicentre randomised controlled trials. Recruitment can be further enhanced by using information videos and group discussions. Trial registration Current Controlled Trials ISRCTN22488978.

Understanding intentions and action in colorectal cancer screening

BACKGROUND

Factors involved in forming intentions to attend cancer screening may be different from those involved in translating intentions into action.

PURPOSE

To test the hypotheses that social cognition variables predict intention better than action, and that life difficulty variables predict action better than intention, in colorectal screening.

METHODS

Participants from one center in the UK Flexible Sigmoidoscopy Trial (n = 2,969) were categorized according to their screening intention, measured at baseline, and their subsequent attendance at screening (recorded at the clinic). Differences in factors related to life difficulty (socioeconomic deprivation, health, stress, social support) and social cognition variables were examined, and discriminant analysis was used to identify sets of variables that best differentiated the groups.

RESULTS

Social cognition variables were strongly associated with intention but only weakly with action. In contrast, factors related to life difficulties (socioeconomic deprivation, poor health status) were better predictors of action than intention.

CONCLUSION

Social cognition variables appeared to be important determinants of screening intentions. Other variables--that may be markers of barriers to implementing plans--were more strongly associated with action. To maximize colorectal screening participation, research is needed to identify a wider range of determinants of attendance.

Attitudes to colorectal cancer screening among ethnic minority groups in the UK

Background

Colorectal screening by Flexible Sigmoidoscopy (FS) is under evaluation in the UK. Evidence from existing cancer screening programmes indicates lower participation among minority ethnic groups than the white-British population. To ensure equality of access, it is important to understand attitudes towards screening in all ethnic groups so that barriers to screening acceptance can be addressed.

Methods

Open- and closed-ended questions on knowledge about colorectal cancer and attitudes to FS screening were added to Ethnibus™ – a monthly, nationwide survey of the main ethnic minority communities living in the UK (Indian, Pakistani, Bangladeshi, Caribbean, African, and Chinese). Interviews (n = 875) were conducted, face-to-face, by multilingual field-workers, including 125 interviews with white-British adults.

Results

All respondents showed a notable lack of knowledge about causes of colorectal cancer, which was more pronounced in ethnic minority than white-British adults. Interest in FS screening was uniformly high (>60%), with more than 90% of those interested saying it would provide 'peace of mind'. The most frequently cited barrier to screening 'in your community' was embarrassment, particularly among ethnic minority groups.

Conclusion

Educational materials should recognise that non-white groups may be less knowledgeable about colorectal cancer. The findings of the current study suggest that embarrassment may be a greater deterrent to participation to FS screening among ethnic minority groups, but this result requires exploration in further research.

Uptake of population-based flexible sigmoidoscopy screening for colorectal cancer: a nurse-led feasibility study

OBJECTIVE

To assess uptake of once-only flexible sigmoidoscopy (FS) in a community sample to determine whether FS would be viable as a method of population-based screening for colorectal cancer.

METHODS

All adults aged 60-64 years registered at three General Practices in North West London, UK (510 men and women) were sent a letter of invitation to attend FS screening carried out by an experienced nurse, followed by a reminder if they did not make contact to confirm or decline the invitation. The primary outcome was attendance at the endoscopy unit for a FS test.

RESULTS

Of the 510 people invited to attend, 280 (55%) underwent FS. Among non-attenders, 91 (18%) were ineligible for screening or did not receive the invitation, 19 (4%) accepted the offer of screening but were unable to attend during the study period, 52 (10%) declined the offer, 41 (8%) did not respond to the invitation, and 27 (5%) accepted the offer of screening but did not attend. Attendance among those eligible to be screened, who had received the invitation, was 67%. People from more socioeconomically deprived neighbourhoods were less likely to attend (odds ratio [OR] = 0.90; confidence interval [CI] = 0.84-0.96; P = 0.003). Women were more likely to attend than men (OR = 1.44; CI = 1.01-2.05; P = 0.041).

CONCLUSIONS

Attendance rates in this pilot for nurse-led, population-based FS screening were higher than those reported in other FS studies, and comparable with adherence to fecal occult blood testing (FOBT) in the UK FOBT pilot. Having a female nurse endoscopist may have been responsible for increasing female uptake rates but this warrants confirmation in a larger study.

Pathways from deprivation to health differed between individual and neighborhood-based indices

OBJECTIVE

To explore the role of behavioral and psychosocial factors in explaining the social gradient in self-rated health as defined either by an individual or a neighborhood deprivation index.

STUDY DESIGN AND SETTING

Data were from the baseline survey of the UK Flexible Sigmoidoscopy trial. Recruitment through general practices was stratified to generate a socioeconomically diverse sample (N=5,253, aged 55-64). Assessments included an individual and neighborhood deprivation index, each of which were categorized in four levels; three behavioral and three psychosocial factors; and self-rated health.

RESULTS

Neighborhood deprivation was more strongly related to behavioral than to psychosocial factors, whereas individual deprivation was strongly related to both. The social gradient in poor self-rated health (odds in most compared to least deprived group) was 6.5 for individual and 4.2 for the neighborhood deprivation index. Behavioral and psychosocial variables explained, respectively, 7% and 11% of the individual deprivation gradient and 11% and 4% of the neighborhood gradient. The psychosocial pathway did not significantly mediate the neighborhood deprivation effect on self-rated health.

CONCLUSION

Intermediary pathways of the social gradient in self-rated health differed between individual and neighborhood-based deprivation indices, suggesting at least partly independent influences on poor health of individual and neighborhood-level deprivation.

Colorectal cancer screening: physicians' knowledge of risk assessment and guidelines, practice, and description of barriers and facilitators

BACKGROUND

Physician nonadherence to colorectal cancer (CRC) screening recommendations contributes to underuse of screening.

OBJECTIVE

To assess physicians' knowledge of CRC screening guidelines for average-risk individuals, perceived barriers to screening and practice behaviours.

METHODS

Between October 2004 and March 2005, staff physicians working in three university-affiliated hospitals in Montreal, Quebec, were surveyed. Self-administered questionnaires assessed knowledge of risk classification and current guidelines for average-risk individuals, as well as perceptions of barriers to screening and practice behaviours.

RESULTS

All 65 invited physicians participated in the survey, including 46 (70.8%) family medicine physicians and 19 (29.2%) general internists. Most physicians knew that screening should begin at 50 years of age, all knew to screen men and women and 92% said they screened average-risk patients. Fifty-seven (87.7%) physicians correctly identified three common characteristics associated with high risk for developing CRC. Physicians who screened average-risk patients preferred fecal occult blood testing (88.3%) and colonoscopy (88.3%) to flexible sigmoidoscopy (10.0%) and double-contrast barium enema (30.0%). Most physicians knew the correct screening periodicity for fecal occult blood testing (87.6%), but only 40% or fewer could identify correct screening periodicities for the other modalities. Barriers and facilitators focused on health care delivery system improvements, better evidence on which to base recommendations and development of practical screening modalities.

CONCLUSIONS

Physicians lacked knowledge of the recommended screening modalities and periodicities to appropriately screen average-risk individuals. Because CRC screening can reduce mortality, efforts to improve physician delivery should focus on physician knowledge and changes to the health care delivery system.

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).

Adverse psychological outcomes in colorectal cancer screening: does health anxiety play a role?

People who are anxious about their health are more likely to misinterpret health information as personally threatening and less likely to be reassured by medical investigations that show they are free from disease. Consequently, health anxious people would be expected to react more adversely to cancer screening, but this possibility has rarely been explored. The moderating role of health anxiety on the psychological impact of participating in colorectal cancer screening was examined among a sub-sample of 3535 participants in a large, community-based trial of colorectal cancer screening in the UK. The screening modality was flexible sigmoidoscopy, which examines the bowel for pre-cancerous polyps. It was predicted that health anxiety would be associated with more worry about cancer before screening, a greater increase in worry if polyps were detected, and less reassurance after a clear result. As expected, health anxious participants were more anxious and more worried about bowel cancer both before and after screening. However, they experienced greater reductions in anxiety and worry about cancer following the examination. They reported lower levels of reassurance following screening, but also expressed more positive reactions to the experience. The positive psychological benefits of attending medical investigations should be examined in future work, because this may go some way towards explaining why health anxious people repeatedly seek medical interventions.

The use of unequal randomisation ratios in clinical trials: a review

OBJECTIVE

To examine reasons given for the use of unequal randomisation in randomised controlled trials (RCTs).

MAIN MEASURES

Setting of the trial; intervention being tested; randomisation ratio; sample size calculation; reason given for randomisation.

METHODS

Review of trials using unequal randomisation. DATABASES AND SOURCES: Cochrane library, Medline, Pub Med and Science Citation Index.

RESULTS

A total of 65 trials were identified; 56 were two-armed trials and nine trials had more than two arms. Of the two-arm trials, 50 trials recruited patients in favour of the experimental group. Various reasons for the use of unequal randomisation were given. Six studies stated that they used unequal randomisation to reduce the cost of the trial, with one screening trial limited by the availability of the intervention. Other reasons for using unequal allocation were: avoiding loss of power from drop-out or cross-over, ethics and the gaining of additional information on the treatment. Thirty seven trials papers (57%) did not state why they had used unequal randomisation and only 14 trials (22%) appeared to have taken the unequal randomisation into account in their sample size calculation.

CONCLUSION

Although unequal randomisation offers a number of advantages to trials the method is rarely used and is especially under-utilised to reduce trial costs. Unequal randomisation should be considered more in trial design especially where there are large differences between treatment costs.

Reduction of clinically manifest colorectal cancer by endoscopic screening: empirical evaluation and comparison of screening at various ages

Endoscopic screening (sigmoidoscopy, colonoscopy) with removal of precancerous lesions can prevent a large proportion of colorectal cancers (CRCs). However, there is lack of data regarding optimal age, time intervals and numbers of screening examinations. We developed and applied modified techniques of epidemiological analysis to evaluate the impact of various endoscopy-based screening strategies on prevention of clinically manifest CRCs between the ages of 50 and 79 in a population-based case-control study (294 cases, 254 controls) conducted in Saarland, Germany. We found a strong potential for reduction of CRC occurrence even with a single screening endoscopy. The optimal age for a single screening endoscopy appears to be around 55 (estimated potential for prevention of cases between the ages of 55 and 79 in case of 100% compliance: 77% (95% confidence interval (CI) 46-90%)). A single screening endoscopy at age 50 would have a lower impact due to failure to prevent CRC at higher ages. Similarly, screening at ages 60 or older would have a lower impact because it would fail to prevent CRC at lower ages. Repeated offers of screening examinations could provide substantial additional benefit with the levels of compliance to be expected in practice, but they would have to be weighed against the increased risks and costs.

Colonoscopic screening of average-risk women for colorectal neoplasia

BACKGROUND

Veterans Affairs (VA) Cooperative Study 380 showed that some advanced colorectal neoplasias (i.e., adenomas at least 1 cm in diameter, villous adenomas, adenomas with high-grade dysplasia, or cancer) in men would be missed with the use of flexible sigmoidoscopy but detected by colonoscopy. In a tandem study, we examined the yield of screening colonoscopy in women.

METHODS

To determine the prevalence and location of advanced neoplasia, we offered colonoscopy to consecutive asymptomatic women referred for colon-cancer screening. The diagnostic yield of flexible sigmoidoscopy was calculated by estimating the proportion of patients with advanced neoplasia whose lesions would have been identified if they had undergone flexible sigmoidoscopy alone. Lesions were considered detectable by flexible sigmoidoscopy if they were in the distal colon or if they were in the proximal colon in patients who had concurrent small adenomas in the distal colon, a finding that would have led to colonoscopy. The results were compared with the results from VA Cooperative Study 380 for age-matched men and women with negative fecal occult-blood tests and no family history of colon cancer.

RESULTS

Colonoscopy was complete in 1463 women, 230 of whom (15.7 percent) had a family history of colon cancer. Colonoscopy revealed advanced neoplasia in 72 women (4.9 percent). If flexible sigmoidoscopy alone had been performed, advanced neoplasia would have been detected in 1.7 percent of these women (25 of 1463) and missed in 3.2 percent (47 of 1463). Only 35.2 percent of women with advanced neoplasia would have had their lesions identified if they had undergone flexible sigmoidoscopy alone, as compared with 66.3 percent of matched men from VA Cooperative Study 380 (P<0.001).

CONCLUSIONS

Colonoscopy may be the preferred method of screening for colorectal cancer in women.

Socioeconomic status differences in coping with a stressful medical procedure

OBJECTIVE

The objective of this study was to test the hypothesis that socioeconomic disadvantage results in adverse emotional reactions to a novel, stressful, medical examination.

METHODS

Sigmoidoscopy screening for colorectal cancer was identified as a potential stressor. A subset of participants (N = 3535) from the U.K. Flexible Sigmoidoscopy Trial completed pre- and postscreening questionnaires regarding psychologic well-being. All trial participants were sent a postscreening questionnaire after 3 months (post-flexible sigmoidoscopy [FS] sample, N = 29,804), including measures of distress (the General Health Questionnaire), anxiety (State-Trait Anxiety Inventory), a single-item measure of bowel cancer worry, and a 6-item measure of positive consequences of screening. Socioeconomic status (SES) was coded from postcodes with the Townsend Index. SES differences in changes in emotional well-being over the course of screening were evaluated in the longitudinal sample. SES differences in postscreening well-being in relation to screening outcome were evaluated in the post-FS sample.

RESULTS

Bowel cancer worry and anxiety were higher in lower SES groups before screening. Both reduced after screening, but there were no SES differences in the change. In the post-FS sample, there was an SES gradient in anxiety but not in distress. Lower SES groups indicated more positive reactions. There were no interactions between SES and screening outcome for any indicator of well-being.

CONCLUSIONS

Lower SES was associated with worse psychologic well-being before and after screening, but lower SES participants did not show any differentially greater adverse reactions compared with higher SES participants. Moderately stressful experiences in everyday life do not necessarily more unfavorably affect those with fewer educational and economic resources.

Multiple rare variants in different genes account for multifactorial inherited susceptibility to colorectal adenomas

Clear-cut inherited Mendelian traits, such as familial adenomatous polyposis or hereditary nonpolyposis colorectal cancer, account for <4% of colorectal cancers. Another 20% of all colorectal cancers are thought to occur in individuals with a significant inherited multifactorial susceptibility to colorectal cancer that is not obviously familial. Incompletely penetrant, comparatively rare missense variants in the adenomatous polyposis coli gene, which is responsible for familial adenomatous polyposis, have been described in patients with multiple colorectal adenomas. These variants represent a category of variation that has been suggested, quite generally, to account for a substantial fraction of such multifactorial inherited susceptibility. The aim of this study was to explore this rare variant hypothesis for multifactorial inheritance by using multiple colorectal adenomas as the model. Patients with multiple adenomas were screened for germ-line variants in a panel of candidate genes. Germ-line DNA was obtained from 124 patients with between 3 and 100 histologically proven synchronous or metachronous adenomatous polyps. All patients were tested for the adenomatous polyposis coli variants I1307K and E1317Q, and variants were also sought in AXIN1 (axin), CTNNB1 (beta-catenin), and the mismatch repair genes hMLH1 and hMSH2. The control group consisted of 483 random controls. Thirty of 124 (24.9%) patients carried potentially pathogenic germ-line variants as compared with 55 ( approximately 12%) of the controls. This overall difference is highly significant, suggesting that many rare variants collectively contribute to the inherited susceptibility to colorectal adenomas.

The incidence of colorectal cancer following a negative screening sigmoidoscopy: implications for screening interval

BACKGROUND & AIMS

Current guidelines recommend a 5-year interval for colorectal cancer (CRC) screening by sigmoidoscopy. However, the optimal screening interval is uncertain. We estimated the annual incidence of distal and proximal CRC in the first 5 years following a negative sigmoidoscopy examination to gauge the potential benefit of rescreening in <5 years.

METHODS

A cohort of 72,483 participants in the Colon Cancer Prevention program of Kaiser Permanente of Northern California (KP) was defined using computerized databases. Men and women aged 50 years and older who had a negative screening flexible sigmoidoscopy examination between 1994 and 1996 and were considered not to be at high risk for developing CRC were included. Subjects were censored at the time of diagnosis (for cases), death, termination of KP membership, or subsequent colon examination.

RESULTS

Thirty cases of distal and 80 cases of proximal CRC occurred. Age-adjusted incidence rates of distal CRC ranged from a low of 2.8 per 100,000 person-years in the first year of follow-up to a high of 13.0 per 100,000 in the fourth year (rate difference, 10.2; 95% confidence interval, 1.1-19.3). However, for the entire follow-up period, incidence of distal CRC remained much lower than age-adjusted rates of 70.6 in the general population (Surveillance, Epidemiology, and End Results registry). The incidence of proximal CRC was also decreased modestly over population rates of disease.

CONCLUSIONS

Screening by sigmoidoscopy more frequently than every 5 years would likely lead, at best, to only modest improvements as compared with a 5-year screening interval.

Socioeconomic differences in cancer screening participation: comparing cognitive and psychosocial explanations

This paper compares psychosocial and cognitive models of socioeconomic variation in participation in screening for colorectal cancer. The psychosocial model suggests that factors such as higher stress and lower social support explain, in part, why people from lower socioeconomic status (SES) environments are less likely to participate in screening. The cognitive model suggests that beliefs about cancer risk and screening will play an important part in differential participation. In practice both sets of factors may contribute to explaining socioeconomic differentials. The data for these analyses are drawn from a randomised controlled trial of colorectal cancer screening (the UK Flexible Sigmoidoscopy Trial). The participants are from the Scottish centre, where recruitment was stratified to generate a socioeconomically diverse sample. The dependent variable was interest in attending screening. A questionnaire covering demographic status, psychosocial and cognitive factors as well as interest in screening was sent to 10,650 adults. The results showed the predicted SES gradient in interest. There were also SES differences in both psychosocial and cognitive variables. A series of logistic regression models were used to test potential mediators of the association between SES and interest in attending screening by successively including psychosocial factors, cognitive factors, and then both, in the equation. Only the inclusion of the cognitive variables significantly reduced the variation associated with SES, providing better support for the cognitive than the psychosocial model.

Wide variation in adenoma detection rates at screening flexible sigmoidoscopy

BACKGROUND & AIMS

Wide between-center variation in adenoma detection rates (ADRs) was observed in the U.K. Flexible Sigmoidoscopy Screening Trial (overall, 12.1%; range, 8.6%-15.9%; P < 0.0001). The aim of this study was to determine whether the observed differences could be attributed to varying performance by endoscopists, to examine the effect of experience on performance, and to identify an attainable, standard ADR to which endoscopists could aspire.

METHODS

Thirteen medical endoscopists, one per trial center, each performed about 3000 examinations (200 per month) using the same equipment and protocol. Overall and monthly ADRs were compared using multivariable logistic regression.

RESULTS

Differences in ADRs were not explained by patient characteristics, incidence of colorectal cancer in the local population, or the endoscopists' medical specialty or previous experience. Average ADRs increased significantly with screening experience (up to 400 examinations). Endoscopists were classified as higher, intermediate, or lower adenoma detectors, and performance levels were maintained over time. Higher detectors had ADRs of 15% overall (men, 20%; women, 10%) and also detected more adenomas per case (higher/lower detectors, 21.7/10.4 adenomas per 100 examinations).

CONCLUSIONS

The differences in ADRs were due to variation in performance of the endoscopists. Long-term follow-up will determine whether this variation is clinically important. We suggest that the standards in higher detecting centers should be achievable by all endoscopists screening unscreened populations aged older than 55 years. Endoscopists should aim to stay above the lower 95% confidence interval band for 200 examinations (10% overall; 5% in women, 15% in men).

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.

Barriers to endoscopic colorectal cancer screening: are women different from men?

OBJECTIVES

The goals of this study were to compare women and men's understanding of screening flexible sigmoidoscopy (FS) and to identify predictors of endoscopic colorectal cancer (CRC) screening.

METHODS

We mailed a 36-item questionnaire to asymptomatic patients aged 50 years or older who were scheduled for routine health assessments at a large multispecialty health-care group. Data collection included demographics, health behaviors, psychosocial factors, and CRC screening compliance. We followed participants for 1 year and assessed completion of endoscopic CRC screening. Both cross-sectional results examining previous screening and prospective results examining screening 1 year later were evaluated.

RESULTS

554 (54%) of 998 patients responded to the survey. Responses of 13 patients were excluded in the analyses due to unverifiable screening outcome. The majority of the respondents were white, and their average age was 62 years. Women reported significantly more embarrassment and fear about having FS than men. Women were more willing to consider having a FS if a female endoscopist performed the procedure. Of the 334 participants who were eligible to have endoscopic CRC screening, 53 (16%) had the procedure within a year. The odds of having the endoscopic procedures increased with the length of time the patients were under the care of their primary care providers and how strongly patients believed that one should have an FS even without symptoms.

CONCLUSION

Our findings suggest some unique gender-specific attitudes and beliefs that act as potential barriers for CRC screening and further support the important role of primary care providers in facilitating timely completion of screening.