Is the type of test used for mass colorectal cancer screening a determinant of compliance? A cluster-randomized controlled trial comparing fecal occult blood testing with flexible sigmoidoscopy

Is there a place for sigmoidoscopy in colorectal cancer screening? A systematic review and critical appraisal of cost-effectiveness models

INTRODUCTION

Screening for colorectal cancer (CRC) is effective in reducing both incidence and mortality. Colonoscopy and stool tests are most frequently used for this purpose. Sigmoidoscopy is an alternative screening measure with a strong evidence base. Due to its distinct characteristics, it might be preferred by subgroups. The aim of this systematic review is to analyze the cost-effectiveness of sigmoidoscopy for CRC screening compared to other screening methods and to identify influencing parameters.

METHODS

A systematic literature search for the time frame 01/2010-01/2023 was conducted using the databases MEDLINE, Embase, EconLit, Web of Science, NHS EED, as well as the Cost-Effectiveness Registry. Full economic analyses examining sigmoidoscopy as a screening measure for the general population at average risk for CRC were included. Incremental cost-effectiveness ratios were calculated. All included studies were critically assessed based on a questionnaire for modelling studies.

RESULTS

Twenty-five studies are included in the review. Compared to no screening, sigmoidoscopy is a cost-effective screening strategy for CRC. When modelled as a single measure strategy, sigmoidoscopy is mostly dominated by colonoscopy or modern stool tests. When combined with annual stool testing, sigmoidoscopy in 5-year intervals is more effective and less costly than the respective strategies alone. The results of the studies are influenced by varying assumptions on adherence, costs, and test characteristics.

CONCLUSION

The combination of sigmoidoscopy and stool testing represents a cost-effective screening strategy that has not received much attention in current guidelines. Further research is needed that goes beyond a narrow focus on screening technology and models different, preference-based participation behavior in subgroups.

Inequalities in participation in colorectal cancer screening programmes: a systematic review

BACKGROUND

Colorectal cancer (CRC) is a major public health problem due to its incidence and mortality. Screening programmes help decrease its impact on the population through early detection. However, the uneven distribution of social determinants of health can cause inequalities. The aim of this study is to identify the social inequalities in the participation in CRC screening programmes.

METHODS

A systematic review of the literature was carried out, searching in both health and social databases for papers published since 2000 in English, Spanish, Portuguese and French. The search strategies combined terms regarding screening, CRC, participation and social inequalities. Included papers were quantitative or qualitative primary studies analyzing gender and socioeconomic inequalities in the participation in CRC screening programmes implemented by public and private health-care providers and addressing 45- to 75-year-old population.

RESULTS

A total of 96 studies, described in 102 articles, were included. Most were quantitative observational studies and analyzed population-based screening programmes. They were carried out mainly in the UK (n=29) and the USA (n=18). Participation in screening programmes varied from 1.1% to 82.8% using several methods. A total of 87 studies assessed participation by sex and one focussed on men, but only two provided an analysis from a gender perspective. Although men are at a higher risk of developing CRC, they generally were less likely to participate in screening programmes. Screening attendance was higher among the least deprived areas.

CONCLUSIONS

Gender and socioeconomic inequalities in CRC screening participation should be addressed through the design of tailored interventions with a multidimensional focus.

Colorectal Cancer Screening in Average Risk Populations: Evidence Summary

Introduction. The objectives of this systematic review were to evaluate the evidence for different CRC screening tests and to determine the most appropriate ages of initiation and cessation for CRC screening and the most appropriate screening intervals for selected CRC screening tests in people at average risk for CRC. Methods. Electronic databases were searched for studies that addressed the research objectives. Meta-analyses were conducted with clinically homogenous trials. A working group reviewed the evidence to develop conclusions. Results. Thirty RCTs and 29 observational studies were included. Flexible sigmoidoscopy (FS) prevented CRC and led to the largest reduction in CRC mortality with a smaller but significant reduction in CRC mortality with the use of guaiac fecal occult blood tests (gFOBTs). There was insufficient or low quality evidence to support the use of other screening tests, including colonoscopy, as well as changing the ages of initiation and cessation for CRC screening with gFOBTs in Ontario. Either annual or biennial screening using gFOBT reduces CRC-related mortality. Conclusion. The evidentiary base supports the use of FS or FOBT (either annual or biennial) to screen patients at average risk for CRC. This work will guide the development of the provincial CRC screening program.

Optimising colorectal cancer screening acceptance: a review

The study aims to review available evidence concerning effective interventions to increase colorectal cancer (CRC) screening acceptance. We performed a literature search of randomised trials designed to increase individuals' use of CRC screening on PubMed, Embase, Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects. Small (≤ 100 subjects per arm) studies and those reporting results of interventions implemented before publication of the large faecal occult blood test trials were excluded. Interventions were categorised following the Continuum of Cancer Care and the PRECEDE-PROCEED models and studies were grouped by screening model (opportunistic vs organised). Multifactor interventions targeting multiple levels of care and considering factors outside the individual clinician control, represent the most effective strategy to enhance CRC screening acceptance. Removing financial barriers, implementing methods allowing a systematic contact of the whole target population, using personal invitation letters, preferably signed by the reference care provider, and reminders mailed to all non-attendees are highly effective in enhancing CRC screening acceptance. Physician reminders may support the diffusion of screening, but they can be effective only for individuals who have access to and make use of healthcare services. Educational interventions for patients and providers are effective, but the implementation of organisational measures may be necessary to favour their impact. Available evidence indicates that organised programmes allow to achieve an extensive coverage and to enhance equity of access, while maximising the health impact of screening. They provide at the same time an infrastructure allowing to achieve a more favourable cost-effectiveness profile of potentially effective strategies, which would not be sustainable in opportunistic settings.

Participation rates for organized colorectal cancer screening programmes: an international comparison

OBJECTIVE

Participation, an indicator of screening programme acceptance and effectiveness, varies widely in clinical trials and population-based colorectal cancer (CRC) screening programmes. We aimed to assess whether CRC screening participation rates can be compared across organized guaiac fecal occult blood test (G-FOBT)/fecal immunochemical test (FIT)-based programmes, and what factors influence these rates.

METHODS

Programme representatives from countries participating in the International Cancer Screening Network were surveyed to describe their G-FOBT/FIT-based CRC screening programmes, how screening participation is defined and measured, and to provide participation data for their most recent completed screening round.

RESULTS

Information was obtained from 15 programmes in 12 countries. Programmes varied in size, reach, maturity, target age groups, exclusions, type of test kit, method of providing test kits and use, and frequency of reminders. Coverage by invitation ranged from 30-100%, coverage by the screening programme from 7-67.7%, overall uptake/participation rate from 7-67.7%, and first invitation participation from 7-64.3%. Participation rates generally increased with age and were higher among women than men and for subsequent compared with first invitation participation.

CONCLUSION

Comparisons among CRC screening programmes should be made cautiously, given differences in organization, target populations, and interpretation of indicators. More meaningful comparisons are possible if rates are calculated across a uniform age range, by gender, and separately for people invited for the first time vs. previously.

Meta-analysis: adherence to colorectal cancer screening and the detection rate for advanced neoplasia, according to the type of screening test

BACKGROUND

A variety of tests have been proposed for colorectal cancer (CRC), giving rise to uncertainty regarding the optimal approach. The efficacy and effectiveness of different tests are related to both screened participation and the detection rate.

AIM

To perform a meta-analysis on adherence and detection rates of CRC screening tests.

METHODS

Relevant publications were identified by MEDLINE/EMBASE and other databases for the period 1999-2012. A previous systematic review was used for the period before 1966-1999. RCTs and controlled studies including a direct comparison of the uptake rates among different options for CRC screening were included. Adherence and detection rates for advanced neoplasia and cancer were extracted. Risk for bias was ascertained according to CONSORT guidelines. Forrest plots were produced based on random-effect models.

RESULTS

Fourteen studies provided data on 197 910 subjects. Endoscopic strategies were associated with a lower participation (RR: 0.67, 95% CI: 0.56, 0.80) rate, but a higher detection rate of advanced neoplasia (RR: 3.21, 95% CI: 2.38, 4.32) compared with faecal tests. FIT was superior to g-FOBT with regard to both adherence (RR: 1.16, 95% CI 1.03, 1.30) and detection of advanced neoplasia (RR: 2.28, 95% CI 1.68, 3.10) and cancer (RR: 1.96, 95% CI: 1.2, 3.2).

CONCLUSION

The superior accuracy of endoscopy compared with faecal tests minimised any impact of the participation rate in determining the detection rate of advanced neoplasia in a screening setting.

Effect of flexible sigmoidoscopy-based screening on incidence and mortality of colorectal cancer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs.

METHODS AND FINDINGS

Medline and Embase databases were searched for eligible articles published between 1966 and 28 May 2012. After screening 3,319 citations and 29 potentially relevant articles, two reviewers identified five RCTs evaluating the effect of FS screening on the incidence and mortality of CRC. The reviewers independently extracted relevant data; discrepancies were resolved by consensus. The quality of included studies was assessed using criteria set out by the Evidence-Based Gastroenterology Steering Group. Random effects meta-analysis was performed. The five RCTs meeting eligibility criteria were determined to be of high methodologic quality and enrolled 416,159 total subjects. Four European studies compared FS to no screening and one study from the United States compared FS to usual care. By intention to treat analysis, FS-based screening was associated with an 18% relative risk reduction in the incidence of CRC (0.82, 95% CI 0.73-0.91, p<0.001, number needed to screen [NNS] to prevent one case of CRC = 361), a 33% reduction in the incidence of left-sided CRC (RR 0.67, 95% CI 0.59-0.76, p<0.001, NNS = 332), and a 28% reduction in the mortality of CRC (relative risk [RR] 0.72, 95% CI 0.65-0.80, p<0.001, NNS = 850). The efficacy estimate, the amount of benefit for those who actually adhered to the recommended treatment, suggested that FS screening reduced CRC incidence by 32% (p<0.001), and CRC-related mortality by 50% (p<0.001). Limitations of this meta-analysis include heterogeneity in the design of the included trials, absence of studies from Africa, Asia, or South America, and lack of studies comparing FS with colonoscopy or stool-based testing.

CONCLUSIONS

This meta-analysis of randomized controlled trials demonstrates that FS-based screening significantly reduces the incidence and mortality of colorectal cancer in average-risk patients.

[Controversial issues in colorectal screening in Hungary: conflict of clinical and public health viewpoints]

In Hungary, mortality rates from colorectal cancer are dramatically high, therefore the reduction by population screening as a public health measure is considered as one of the priorities of National Public Health Program. In the beginning, a human-specific immunological test was applied in the "model programs", as a screening tool, to detect the occult blood in the stool; compliance was 32% in average. However, the objectives of the model programs have not been achieved, because, among other reasons, a debate on the method of choice and the strategy to follow have divided the professional public opinion. In this study the debated issues are critically discussed, being convinced that, at present, population screening seems to be the most promising way to alleviate the burden of colorectal cancer.

Cluster randomized trials of cancer screening interventions: are appropriate statistical methods being used?

The design and analysis of cluster randomized trials can require more sophistication than individually randomized trials. However, the need for statistical methods that account for the clustered design has not always been appreciated, and past reviews have found widespread deficiencies in methodology and reporting. We reviewed cluster randomized trials of cancer screening interventions published in 1995-2010 to determine whether the use of appropriate statistical methods had increased over time. Literature searches yielded 50 articles reporting outcome analyses of cluster randomized trials of breast, cervix and colorectal cancer screening interventions. Of studies published in 1995-1999, 2000-2002, 2003-2006 and 2007-2010, 55% (6/11), 82% (9/11), 92% (12/13) and 60% (9/15) used appropriate analytic methods, respectively. Results were suggestive of a peak in 2003-2006 (p =.06) followed by a decline in 2007-2010 (p =.08). While the sample of studies was small, these results indicate that many cluster randomized trials of cancer screening interventions have had deficiencies in the application of correct statistical procedures for the outcome analysis, and that increased adoption of appropriate methods in the early and mid-2000's may not have been sustained.

Does participation to screening unintentionally influence lifestyle behaviour and thus lifestyle-related morbidity?

Cancer is a leading cause of death worldwide and the burden could be reduced by evidence-based strategies for the primary prevention of cancer, the early detection of malignancies and more adequate treatment of cancer patients. Previous research has shown that lifestyle factors are associated with common cancers and that several cancer screening programmes are cost-effective in reducing cancer-specific mortality. But, some recent studies reported that participants of screening programs might unintentionally change their lifestyle. Cancer screening might be a teachable moment or, on the other hand, have a false health certificate effect. Despite that the evidence is scarce, cancer screening might have opportunities for lifestyle improvements, although a possible health certificate effect still remains. Integrated approaches to combine primary and secondary prevention have the potential to optimise the efforts to improve cancer prevention and survival. More research is warranted to investigate evidence-based approaches.

Comparing different strategies for colorectal cancer screening in Italy: predictors of patients' participation

OBJECTIVES

The objective of this study was to study predictors of patients' participation in colorectal cancer (CRC) screening.

METHODS

Men and women, aged 55-64 years, were randomized to the following: (i) biennial fecal occult blood test (FOBT) delivered by mail (n=2,266); (ii) FOBT delivered by a general practitioner (GP)/screening facility (n=5,893); (iii) "once-only" sigmoidoscopy (FS) (n=3,650); (iv) FS followed by FOBT for screenees with negative FS (n=10,867); and (v) patient's choice between FS and FOBT (n=3,579). A stratified (by screening arm) random sample of attenders and nonattenders was contacted by trained interviewers 4 months after the initial invitation. Subjects giving their consent were administered a questionnaire (available online) investigating perceptions of individual CRC risk, attitudes toward prevention, adoption of health protective behaviors, and reasons for attendance/nonattendance. Adjusted prevalence odds ratios (ORs) were computed by multivariable logistic regression.

RESULTS

The response rate was 71.9% (701 of 975) among nonattenders and 88.9% (773 of 870) among attenders. Adjusting for screening arm, center, gender, age, and education, participation was significantly higher among people who consulted their GP before undergoing screening (OR: 4.24; 95% confidence interval (CI): 3.11-5.78), who mentioned one first-degree relative with CRC (OR: 3.62; 95% CI: 2.02-6.49), who reported regular physical activity (OR: 1.85; 95% CI: 1.33-2.55), and who read the mailed information (letter only: OR: 1.85; 95% CI: 1.23-2.78; letter+leaflet: OR: 3.18; 95% CI: 2.12-4.76). People who considered screening to be ineffective (OR: 0.12; 95% CI: 0.08-0.19), those who considered it to be effective but reported even moderate levels of anxiety (OR: 0.32; 95% CI: 0.23-0.45), and those who mentioned previous knowledge of CRC screening tests were less likely to accept the invitation (OR: 0.49; 95% CI: 0.34-0.70).

CONCLUSIONS

Adoption of health protective behaviors is associated with a higher attendance rate, whereas anxiety represents a strong barrier, even among people who deemed screening to be effective. Increasing the proportion of people who consult their GP when making a decision regarding screening might enhance participation.

Barriers to colorectal cancer screening: A case-control study

AIM: To investigate barriers to colorectal cancer (CRC) screening in a community population.

METHODS: We conducted a community-based case-control study in an urban Chinese population by questionnaire. Cases were selected from those completing both a fecal occult blood test (FOBT) case and colonoscopy in a CRC screening program in 2004. Control groups were matched by gender, age group and community. Control 1 included those having a positive FOBT but refusing a colonoscopy. Control 2 included those who refused both an FOBT and colonoscopy.

RESULTS: The impact of occupation on willingness to attend a colorectal screening program differed by gender. P for heterogeneity was 0.009 for case vs control group 1, 0.01 for case versus control group 2, and 0.80 for control group 1 vs 2. Poor awareness of CRC and its screening program, characteristics of screening tests, and lack of time affected the screening rate. Financial support, fear of pain and bowel preparation were barriers to a colonoscopy as a screening test. Eighty-two percent of control group 1 and 87.1% of control group 2 were willing attend if the colonoscopy was free, but only 56.3% and 53.1%, respectively, if it was self-paid. Multivariate odds ratios for case vs control group 1 were 0.10 among those unwilling to attend a free colonoscopy and 0.50 among those unwilling to attend a self-paid colonoscopy.

CONCLUSION: Raising the public awareness of CRC and its screening, integrating CRC screening into the health care system, and using a painless colonoscopy would increase its screening rate.

Can colorectal cancer mass-screening organization be evidence-based? Lessons from failures: the experimental and pilot phases of the Lazio program

Background

Screening programmes should be organized to translate theoretical efficacy into effectiveness. An evidence-based organizational model of colorectal cancer screening (CRCS) should assure feasibility and high compliance.

Methods

A multidisciplinary Working Group (WG), reviewed literature and guidelines to define evidence-based recommendations. The WG identified the need for further local studies: physicians' CRCS attitudes, the effect of test type and provider on compliance, and individual reasons for non-compliance. A survey of digestive endoscopy services was conducted. A feasibility study on a target population of 300.000 has begun.

Results

Based on the results of population trials and on literature review the screening strategy adopted was Faecal Occult Blood Test (FOBT) every two years for 50–74 year olds and, for positives, colonoscopy. The immunochemical test was chosen because it has 20% higher compliance than the Guaiac. GPs were chosen as the preferred provider also for higher compliance. Since we observed that distance is the major determinant of non-compliance, we choose GPs because they are the closest providers, both geographically and emotionally, to the public.

The feasibility study showed several barriers: GP participation was low, there were administrative problems to involve GPs; opportunistic testing by the GPs; difficulties in access to Gastroenterology centres; difficulties in gathering colonoscopy results; little time given to screening activity by the gastroenterology centre.

Conclusion

The feasibility study highlighted several limits of the model. Most of the barriers that emerged were consequences of organisational choices not supported by evidence. The principal limit was a lack of accountability by the participating centres.

Implementation of colon cancer screening: techniques, costs, and barriers

Colorectal cancer and breast cancer are the only cancer sites for which evidence on the efficacy of screening is available from randomized trials. The trials on colon cancer screening in the United States and Europe used the fecal occult blood test as the primary screen, but randomized trial data are not yet available on endoscopy (flexible sigmoidoscopy to 60 cm), and no randomized, controlled trials of colonoscopy as a screening test are in progress. This article reviews colorectal cancer screening from an epidemiologist's perspective to provide the theoretic evidence-based underpinning for the role of the gastroenterologist in colorectal screening.