Effect of dietary restriction on participation in faecal occult blood test screening for colorectal cancer

Colonoscopy Versus Fecal Immunochemical Test for Reducing Colorectal Cancer Risk: A Population-Based Case-Control Study

INTRODUCTION

Use of colonoscopy or the fecal immunochemical test (FIT) for colorectal cancer (CRC) prevention is supported by previous studies. However, there is little specific evidence regarding comparative effectiveness of colonoscopy or FIT for reducing CRC risk. In this study, we compared the association of CRC risk with colonoscopy and FIT using a nationwide database.

METHODS

This population-based case-control study used colonoscopy and FIT claims data from the Korean National Health Insurance System from 2002 to 2013. Data were analyzed from 61,221 patients with newly diagnosed CRC (case group) and 306,099 individuals without CRC (control group). Multivariable logistic regression models were used to evaluate the association between CRC and colonoscopy or FIT.

RESULTS

Colonoscopy was associated with a reduced subsequent CRC risk (adjusted odds ratio [OR] 0.29). Stronger associations were found between colonoscopy and distal CRC, compared with proximal CRC (0.24 vs 0.47). In an analysis stratified by sex, the association was weaker in female subjects compared with male subjects (0.33 vs 0.27). Any FIT exposure was associated with CRC risk with an OR of 0.74; this association was stronger for distal cancer. As the frequency of cumulative FIT assessments increased (from 1 to ≥5), the OR of FIT exposure for CRC gradually decreased from 0.81 to 0.45.

DISCUSSION

The association of colonoscopy or FIT with reduced CRC risk was stronger for distal CRC than for proximal CRC. FIT showed less CRC risk reduction than colonoscopy. However, as the frequency of cumulative FIT assessments increased, the association with CRC prevention became stronger.

MicroRNAs as potential investigative and predictive biomarkers in colorectal cancer

Colorectal cancer (CRC) is a noticeable reason of cancer-associated deaths with a high incidence and mortality rate. Countless effort have been put into the improving clinical management of CRC patients including more effective tools and a wide variety of biomarkers for diagnostic, prognostic or predictive purposes. In recent years, dysregulated miRNAs have been emerged as highly sensitive and specific markers to manage CRC in an effective way. They can play key roles in carcinogenesis as potential oncogenes, tumor suppressors or regulators of cancer network. Therefore, miRNAs may serve as molecular tools that can be quantified and used in diagnostic and prognostic approaches. Growing evidence also suggests that forced expression of tumor suppressor miRNAs or inhibiting the oncogene ones, can be used as a novel treatment strategy. In this review, we focus on the clinical applications of miRNAs as promising biomarkers of early cancer detection, prognosis and treatment.

Colorectal Cancer Biomarkers - A New Trend in Early Diagnosis

Colorectal cancer (CRC) is one of the most widespread malignancy, posing as a great challenge due to its high incidence and mortality in both genders. Yet, it also stands as one of the most preventable diseases because of its known malignant transformation mostly from tubular adenomas or serrated polyps, therefore offering a strong incentive to the screening programs that are being developed for this disease. Current diagnosis of CRC has surely evolved along with the evolutionary step in gastrointestinal technology of flexible endoscopy. These innovations have promoted colonoscopy as a primary choice for screening programs of colonic lesions, proving to be of great benefit for patient’s well-being. In this review, we present the current status of CRC screening methods from the non-invasive options to the long developed colonoscopic and imaging techniques. We search through PubMed and Medline databases and chose relevant articles on CRC with focus on blood based biomarkers and stool based tests. Additional relevant publications were also according to the reference lists of firstly identified articles.

Colorectal Cancer Screening: Stool DNA and Other Noninvasive Modalities

Colorectal cancer screening dates to the discovery of pre-cancerous adenomatous tissue. Screening modalities and guidelines directed at prevention and early detection have evolved and resulted in a significant decrease in the prevalence and mortality of colorectal cancer via direct visualization or using specific markers. Despite continued efforts and an overall reduction in deaths attributed to colorectal cancer over the last 25 years, colorectal cancer remains one of the most common causes of malignancy-associated deaths. In attempt to further reduce the prevalence of colorectal cancer and associated deaths, continued improvement in screening quality and adherence remains key. Noninvasive screening modalities are actively being explored. Identification of specific genetic alterations in the adenoma-cancer sequence allow for the study and development of noninvasive screening modalities beyond guaiac-based fecal occult blood testing which target specific alterations or a panel of alterations. The stool DNA test is the first noninvasive screening tool that targets both human hemoglobin and specific genetic alterations. In this review we discuss stool DNA and other commercially available noninvasive colorectal cancer screening modalities in addition to other targets which previously have been or are currently under study.

A Randomised Trial of the Impact of New Faecal Haemoglobin Test Technologies on Population Participation in Screening for Colorectal Cancer

OBJECTIVES

To investigate the effect on participation in colorectal cancer screening of testing for blood products in faeces using technologies that remove dietary restrictions (i.e. immunochemical tests) and simplify faecal sampling (i.e. tests that use brush sampling).

METHODS

SETTING

Urban residents (n=1818) of Adelaide, Australia, aged between 50 and 69 years, randomly selected from the electoral roll.

DESIGN

Three randomised cohorts of 606 invitees were offered a screening test by mail in 2001. The Hemoccult SENSA and FlexSure OBT cohorts were instructed to sample three stools using a spatula while the InSureTM cohort sampled two stools using a brush. The Hemoccult SENSA cohort was asked to restrict certain (high-peroxidase) foods and drugs.

MAIN OUTCOME MEASURES

Participation (i.e. return of completed sample kits within 12 weeks) and generalised linear modelling (GLM) of relationships between participation, test technologies and demographic variables.

RESULTS

Participation was 23.4%, 30.5% and 39.6% for the Hemoccult, FlexSure and InSure cohorts, respectively (chi(2)=37.1, p<0.00001). GLM demonstrated that participation was increased by 28% by removal of restrictions (p=0.01) and by 30% by simplification of sampling (p=0.001); both together increased participation by 66% (p<0.001). The differences in participation between tests occurred in the first three weeks. Socio-economic status, gender or age did not significantly influence technology-based improvements in participation.

CONCLUSIONS

The brush-sampling faecal immunochemical test for haemoglobin (InSure) achieves the best participation rates by simplifying sampling and removing the need for restrictions of diet and drugs. Because participation in screening is vital to detection, this new technology should contribute to better detection of neoplasia at the population level.

Prescreening Evaluation of a Brush-Based Faecal Immunochemical Test for Haemoglobin

OBJECTIVES

To undertake a prescreening evaluation of a new brush-based faecal immunochemical test for haemoglobin, relative to a traditional spatula-sampling immunochemical test.

METHODS

SETTING

Patients aged between 24 and 90 years, scheduled to undergo diagnostic colonoscopy in two major urban hospitals, for a range of clinical indications.

DESIGN

Patients sampled three stools using a spatula for the reference FlexSure OBT test and two stools using a brush for the InSure test; order of sampling was randomised. Faecal haemoglobin was quantified by a modified InSure in a subset of patients to determine whether brush-sampling allowed discrimination between groups.

MAIN OUTCOME MEASURES

Sensitivity for cancer or adenoma; false-positive rate in normals. Faecal haemoglobin levels. Preference for sampling method.

RESULTS

InSure and FlexSure OBT did not differ in their sensitivities for cancer (27/36, 75% vs 29/36, 80.5%, respectively), adenomas >or= 10 mm (12/29, 41.4% vs 13/29, 44.8%) or adenomas <10 mm (each 8/56, 14.3%). Likewise, false-positive rates in normals were similar: 4/179 (2.2%) and 5/179 (2.8%) respectively (specificities of 97.8% and 97.2%, respectively). Levels of faecal haemoglobin were highest in those with cancers; those with adenomas had intermediate levels which were also significantly higher than those in normals. The brush sampling method was preferred by 38/46 (82.6%), while 4/46 (8.7%) preferred the spatula (p<0.00001).

CONCLUSIONS

InSure is as sensitive and specific as FlexSure OBT for faecal haemoglobin. The novel stool-sampling method of InSure allows discrimination between normals and classes of neoplasia, and is highly preferred. The brush-sampling faecal immunochemical test InSure should now be evaluated in a screening population.

Correlating Quantitative Fecal Immunochemical Test Results with Neoplastic Findings on Colonoscopy in a Population-Based Colorectal Cancer Screening Program: A Prospective Study

Background and Aims. The Canadian Partnership Against Cancer (CPAC) recommends a fecal immunochemical test- (FIT-) positive predictive value (PPV) for all adenomas of ≥50%. We sought to assess FIT performance among average-risk participants of the British Columbia Colon Screening Program (BCCSP). Methods. From Nov-2013 to Dec-2014 consecutive participants of the BCCSP were assessed. Data was obtained from a prospectively collected database. A single quantitative FIT (NS-Plus, Alfresa Pharma Corporation, Japan) with a cut-off of ≥10 μg/g (≥50 ng/mL) was used. Results. 20,322 FIT-positive participants underwent CSPY. At a FIT cut-off of ≥10 μg/g (≥50 ng/mL) the PPV for all adenomas was 52.0%. Increasing the FIT cut-off to ≥20 μg/g (≥100 ng/mL) would increase the PPV for colorectal cancer (CRC) by 1.5% and for high-risk adenomas (HRAs) by 6.5% at a cost of missing 13.6% of CRCs and 32.4% of HRAs. Conclusions. As the NS-Plus FIT cut-off rises, the PPV for CRC and HRAs increases but at the cost of missed lesions. A cut-off of ≥10 μg/g (≥50 ng/mL) produces a PPV for all adenomas exceeding national recommendations. Health authorities need to take into consideration endoscopic resources when selecting a FIT positivity threshold.

Colorectal Cancer Screening

Colorectal cancer (CRC) is a leading cause of cancer morbidity and mortality in the Western world. Advances in surgical and medical management have led to improved outcomes; however, the prognosis of CRC is often poor when detected at a symptomatic stage. Most cases of CRC develop over years from removable well-defined precursor lesions, and asymptomatic, curable disease may be detected by convenient noninvasive tests. These features make CRC a suitable candidate for screening, and several options are available. This article outlines the evidence for established CRC screening tests along with a discussion on newer tests and ongoing research.

Improving uptake of screening for colorectal cancer: a study on invitation strategies and different test kit use

OBJECTIVE

The aim of this study was to compare the uptake of mail-delivered tests for colorectal cancer screening. We assessed the effect of an advance notification letter and a reminder letter, and analysed the proportion of inappropriately handled tests.

MATERIALS AND METHODS

Fifteen thousand randomly selected residents of Latvia aged 50-74 years were allocated to receive one of three different test systems: either a guaiac faecal occult blood test (gFOBT) or one of two laboratory-based immunochemical tests (FIT) - FOB Gold or OC-Sensor. Half of the target population received an advance notification letter; all nonresponders were sent a reminder letter.

RESULTS

The uptake of screening was 31.2% for the gFOBT, 44.7% for FOB Gold and 47.4% for the OC-Sensor (odds ratio 0.55; 95% confidence interval 0.51-0.60 for gFOBT vs. FOB Gold; odds ratio 0.90; 95% confidence interval 0.83-0.98 for FOB Gold vs. OC-Sensor). The uptake in the gFOBT group was improved by the advance notification letter (7.7%, P<0.0001). 30.9% returned tests were received after the reminder letter. The proportion of tests that could not be analysed because of inadequate handling was 0.9% for gFOBT, 4.4% for FOB Gold and 0.2% for the OC-Sensor (P=0.002 for gFOBT vs. OC-Sensor; P<0.001 for all comparisons vs. FOB Gold).

CONCLUSION

The use of FIT resulted in higher uptake. Receipt of a reminder letter was critical to participation, but the use of an advance notification letter was important mainly for gFOBT. The proportion of inappropriately handled tests was markedly higher for FOB Gold.

An updated Asia Pacific Consensus Recommendations on colorectal cancer screening

OBJECTIVE

Since the publication of the first Asia Pacific Consensus on Colorectal Cancer (CRC) in 2008, there are substantial advancements in the science and experience of implementing CRC screening. The Asia Pacific Working Group aimed to provide an updated set of consensus recommendations.

DESIGN

Members from 14 Asian regions gathered to seek consensus using other national and international guidelines, and recent relevant literature published from 2008 to 2013. A modified Delphi process was adopted to develop the statements.

RESULTS

Age range for CRC screening is defined as 50-75 years. Advancing age, male, family history of CRC, smoking and obesity are confirmed risk factors for CRC and advanced neoplasia. A risk-stratified scoring system is recommended for selecting high-risk patients for colonoscopy. Quantitative faecal immunochemical test (FIT) instead of guaiac-based faecal occult blood test (gFOBT) is preferred for average-risk subjects. Ancillary methods in colonoscopy, with the exception of chromoendoscopy, have not proven to be superior to high-definition white light endoscopy in identifying adenoma. Quality of colonoscopy should be upheld and quality assurance programme should be in place to audit every aspects of CRC screening. Serrated adenoma is recognised as a risk for interval cancer. There is no consensus on the recruitment of trained endoscopy nurses for CRC screening.

CONCLUSIONS

Based on recent data on CRC screening, an updated list of recommendations on CRC screening is prepared. These consensus statements will further enhance the implementation of CRC screening in the Asia Pacific region.

Advances in Fecal Occult Blood Tests: the FIT revolution

There is a wide choice of fecal occult blood tests (FOBTs) for colorectal cancer screening.

GOAL

To highlight the issues applicable when choosing a FOBT, in particular which FOBT is best suited to the range of screening scenarios. Four scenarios characterize the constraints and expectations of screening programs: (1) limited colonoscopy resource with a need to constrain test positivity rate; (2) a priority for maximum colorectal neoplasia detection with little need to constrain colonoscopy workload; (3) an "adequate" endoscopy resource that allows balancing the benefits of detection with the burden of service provision; and (4) a need to maximize participation in screening. Guaiac-based FOBTs (gFOBTs) have significant deficiencies, and fecal immunochemical tests (FITs) for hemoglobin have emerged as better tests. gFOBTs are not sensitive to small bleeds, specificity can be affected by diet or drugs, participant acceptance can be low, laboratory quality control opportunities are limited, and they have a fixed hemoglobin concentration cutoff determining positivity. FITs are analytically more specific, capable of quantitation and hence provide flexibility to adjust cutoff concentration for positivity and the balance between sensitivity and specificity. FITs are clinically more sensitive for cancers and advanced adenomas, and because they are easier to use, acceptance rates are high.

CONCLUSIONS

FOBT must be chosen carefully to meet the needs of the applicable screening scenario. Quantitative FIT can be adjusted to suit Scenarios 1, 2 and 3, and for each, they are the test of choice. FITs are superior to gFOBT for Scenario 4 and gFOBT is only suitable for Scenario 1.

Implementation intentions and colorectal screening: a randomized trial in safety-net clinics

CONTEXT

Low-income and racial/ethnic minority populations experience disproportionate colorectal cancer (CRC) burden and poorer survival. Novel behavioral strategies are needed to improve screening rates in these groups.

BACKGROUND

The study aimed to test a theoretically based "implementation intentions" intervention for improving CRC screening among unscreened adults in urban safety-net clinics.

DESIGN

Randomized controlled trial.

SETTING/PARTICIPANTS

Adults (N=470) aged ≥50 years, due for CRC screening, from urban safety-net clinics were recruited.

INTERVENTION

The intervention (conducted in 2009-2011) was delivered via touchscreen computers that tailored informational messages to decisional stage and screening barriers. The computer then randomized participants to generic health information on diet and exercise (Comparison group) or "implementation intentions" questions and planning (Experimental group) specific to the CRC screening test chosen (fecal immunochemical test or colonoscopy).

MAIN OUTCOME MEASURES

The primary study outcome was completion of CRC screening at 26 weeks based on test reports (analysis conducted in 2012-2013).

RESULTS

The study population had a mean age of 57 years and was 42% non-Hispanic African American, 28% non-Hispanic white, and 27% Hispanic. Those receiving the implementation intentions-based intervention had higher odds (AOR=1.83, 95% CI=1.23, 2.73) of completing CRC screening than the Comparison group. Those with higher self-efficacy for screening (AOR=1.57, 95% CI=1.03, 2.39), history of asthma (AOR=2.20, 95% CI=1.26, 3.84), no history of diabetes (AOR=1.86, 95% CI=1.21, 2.86), and reporting they had never heard that "cutting on cancer" makes it spread (AOR=1.78, 95% CI=1.16, 2.72) were more likely to complete CRC screening.

CONCLUSIONS

The results of this study suggest that programs incorporating an implementation intentions approach can contribute to successful completion of CRC screening even among very low-income and diverse primary care populations. Future initiatives to reduce CRC incidence and mortality disparities may be able to employ implementation intentions in large-scale efforts to encourage screening and prevention behaviors.

Fecal-based colorectal cancer screening among the uninsured in northern Manhattan

BACKGROUND

Colorectal cancer (CRC) screening reduces CRC mortality; however, for many reasons, uninsured individuals are less likely to utilize CRC screening tests.

PURPOSE

To compare CRC screening behaviors and outcomes with guaiac fecal occult blood testing (gFOBT) from 1998 to 2006 and fecal immunochemical testing (FIT) from 2006 to 2010 in a community-based program serving uninsured patients in northern Manhattan.

METHODS

In 2013, we conducted a retrospective record review of individuals aged ≥50 years who received fecal-based CRC screening at the Northern Manhattan Cancer Screening Partnership between 1998 and 2010. Included were those with household income ≤250% of the federal poverty level, no medical insurance coverage, and who were not up to date with CRC screening. We assessed screening positivity rate, positive predictive value, differences in the use of diagnostic colonoscopy, colonoscopic findings, and adenoma detection rates for gFOBT versus FIT.

RESULTS

In total, 7,710 patients completed CRC screenings (4,951 gFOBT and 2,759 FIT). The majority were female, Hispanic, foreign born, and young at age of first screening. Compared to gFOBT, FIT detected twice as many positive tests (3.2% vs 1.5%, p≤0.001) and had a higher adenoma detection rate (18.2 vs 11.8, p=0.002).

CONCLUSIONS

The improved positivity and adenoma detection rates with greater number of screening tests over time favor the use of FIT over gFOBT for colorectal screening among uninsured populations in northern Manhattan.

Tests and investigations for colorectal cancer screening

Worldwide, colorectal (CRC) is the third most common form of cancer, after lung and breast cancer, and the fourth most common cause of cancer death, although in developed countries CRC incidence is higher and it accounts for an even higher proportion of cancer deaths. Successful treatment of early-stage CRC confers substantial survival advantage, and there is now overwhelming evidence that screening average-risk individuals for CRC reduces the incidence and disease-specific mortality. In spite of considerable research for new biomarkers for CRC, the detection of blood in faeces remains the most effective screening tool. The best evidence to date for population-based CRC screening comes from randomised-controlled trials that used a guaiac-based faecal occult blood test (gFOBt) as the first-line screening modality, whereby test-positive individuals are referred for follow-up investigations, usually colonoscopy. A major innovation in the last ten years or so has been the development of other more analytically sensitive and specific screening techniques for blood in faeces. The faecal immunochemical test for haemoglobin (FIT) confers substantial benefits over gFOBt in terms of analytical sensitivity, specificity and practicality and FIT are now recommended for CRC screening by the European guidelines for quality assurance in colorectal cancer screening and diagnosis. The challenge internationally is to develop high quality CRC screening programmes for which uptake is high. This is especially important for developing countries witnessing an increase in the incidence of CRC as populations adopt more westernised lifestyles. This review describes the tests available for CRC screening and how they are being used worldwide. The reader will gain an understanding of developments in CRC screening and issues that arise in choosing the most appropriate screening test (or tests) for organised population-based screening internationally and optimising the performance of the chosen test (or tests). Whilst a wide range of literature has been cited, this is not a systematic review. The authors provide FOBT CRC screening for a population of 14.6 million in the south of England and the senior author (SPH) was the lead author of the European guidelines for quality assurance in colorectal cancer screening and diagnosis and leads the World Endoscopy Organization Colorectal Cancer Committee's Expert Working Group on 'FIT for Screening'.

Population screening for colorectal cancer means getting FIT: the past, present, and future of colorectal cancer screening using the fecal immunochemical test for hemoglobin (FIT)

Fecal immunochemical tests for hemoglobin (FIT) are changing the manner in which colorectal cancer (CRC) is screened. Although these tests are being performed worldwide, why is this test different from its predecessors? What evidence supports its adoption? How can this evidence best be used? This review addresses these questions and provides an understanding of FIT theory and practices to expedite international efforts to implement the use of FIT in CRC screening.

FIT testing: an overview

Colorectal cancer (CRC) is a common, but preventable, disease and is the second most common cause of cancer-related deaths in the U.S. CRC screening has proven effective at reducing both the incidence and mortality of this disease, using any of a number of screening tests available. The test options range from the least invasive and least expensive to more invasive and costly options. Fecal occult blood testing is the oldest, least expensive, and least invasive of these options and has evolved from the poorly sensitive standard guaiac test to the newer and diagnostically superior fecal immunochemical test (FIT) for hemoglobin. This article explores the evolutionary history of fecal occult blood testing, examines test performance characteristics among different FOBTs, and evaluates the role of the FIT in programmatic CRC screening.

Cost effectiveness of fecal DNA screening for colorectal cancer: a systematic review and quality appraisal of the literature

BACKGROUND

Fecal DNA (fDNA) testing is a noninvasive potential alternative to current colorectal cancer screening tests.

OBJECTIVE

We conducted a systematic review and quality assessment of studies of cost-effectiveness of fDNA as a colorectal cancer screening tool (compared with no screening and other screening modalities), and identified key variables that impinged on cost-effectiveness.

DATA SOURCES

We searched MEDLINE, Embase, and the Centre for Reviews and Dissemination for cost-effectiveness studies of fDNA-based screening, published in English by September 2011.

STUDY SELECTION

Studies that undertook an economic evaluation of fDNA, using either a cost-effectiveness or cost-utility analysis, compared with other relevant screening modalities and/or no screening were included. Additional inclusion criteria related to the presentation of data pertaining to model variables including time horizon, costs, fDNA performance characteristics, screening uptake, and comparators. A total of 369 articles were initially identified for review. After removing duplicates and applying inclusion and exclusion criteria, seven articles were included in the final review.

STUDY APPRAISAL

Data was abstracted on key descriptor variables including screening scenarios, time horizon, costs, test performance characteristics, screening uptake, comparators, and incremental cost-effectiveness ratios. Quality assessment was undertaken using a standard checklist for economic evaluations. Studies cited by cost-effectiveness articles as the source of data on fDNA test performance characteristics were also reviewed.

RESULTS

Seven cost-effectiveness studies were included, from the USA (4), Canada (1), Israel (1), and Taiwan (1). Markov models (5), a partially observable Markov decision process model (1) and MISCAN and SimCRC (1) microsimulation models were used. All studies took a third-party payer perspective and one included, in addition, a societal perspective. Comparator screening tests, screening intervals, and specific fDNA tests varied between studies. fDNA sensitivity and specificity parameters were derived from 12 research studies and one meta-analysis. Outcomes assessed were life-years gained and quality-adjusted life-years gained. fDNA was cost-effective when compared with no screening in six studies. Compared with other screening modalities, fDNA was not considered cost-effective in any of the base-case analyses: in five studies it was dominated by all alternatives considered. Sensitivity analyses identified cost, compliance, and test parameters as key influential parameters. In general, poor presentation of "study design" and "data collection" details lowered the quality of included articles.

LIMITATIONS

Although the literature searches were designed for high sensitivity, the possibility cannot be excluded that some eligible studies may have been missed. Reports (such as Health Technology Assessments produced by government agencies) and other forms of grey literature were excluded because they are difficult to identify systematically and/or may not report methods and results in sufficient detail for assessment.

CONCLUSION

On the basis of the available (albeit limited) evidence, while fDNA is cost-effective when compared with no screening, it is currently dominated by most of the other available screening options. Cost and test performance appear to be the main influences on cost-effectiveness.

Psychosocial variables associated with colorectal cancer screening in South Australia

BACKGROUND

Population screening reduces mortality from colorectal cancer, yet factors associated with uptake of screening are incompletely understood.

PURPOSE

The purpose of the study was to determine demographic and psychosocial factors associated with participation in faecal occult blood test (FOBT)-based colorectal cancer (CRC) screening in an average risk community programme in Adelaide, South Australia.

METHOD

A questionnaire consistent with the Preventive Health Model was used to determine demographic and psychosocial differences between previous FOBT-based screening participants (n = 413, response rate 93.2%) and non-participants (n = 481, response rate 47.9%). Results were analysed by univariate and multivariate generalised linear modelling, and factors associated with participation were identified.

RESULTS

Factor analysis of psychosocial items revealed an optimal three-factor solution (knowledge, faecal aversion, belief in the value of screening). Following multivariate analyses, two psychosocial and two demographic factors remained as predictors of FOBT screening behaviour: (1) items related to faecal aversion (Aversion), relative risk (RR) = 0.61, CI = 0.55-0.69, (2) perceptions about the value of screening (Value), RR = 1.45, CI = 1.13-1.85, (3) age band 65-69 (Age, five age bands, relative to age 50-54), RR = 1.43, CI = 1.16-1.76 and FOBT type (Test; three tests, Hemoccult, FlexSure, InSure randomly assigned, relative to Hemoccult: FlexSure: RR = 1.41, CI = 1.17-1.71, InSure: RR = 1.76, CI = 1.47-2.11.

CONCLUSIONS

The psychosocial factors associated with non-participation in FOBT-based CRC screening are amenable to interventions designed to improve participation. The small relative risks values associated with each predictor, however, raise the possibility that additional factors are likely to influence screening participation.

Cost-effectiveness of population-based screening for colorectal cancer: a comparison of guaiac-based faecal occult blood testing, faecal immunochemical testing and flexible sigmoidoscopy

BACKGROUND

Several colorectal cancer-screening tests are available, but it is uncertain which provides the best balance of risks and benefits within a screening programme. We evaluated cost-effectiveness of a population-based screening programme in Ireland based on (i) biennial guaiac-based faecal occult blood testing (gFOBT) at ages 55-74, with reflex faecal immunochemical testing (FIT); (ii) biennial FIT at ages 55-74; and (iii) once-only flexible sigmoidoscopy (FSIG) at age 60.

METHODS

A state-transition model was used to estimate costs and outcomes for each screening scenario vs no screening. A third party payer perspective was adopted. Probabilistic sensitivity analyses were undertaken.

RESULTS

All scenarios would be considered highly cost-effective compared with no screening. The lowest incremental cost-effectiveness ratio (ICER vs no screening euro 589 per quality-adjusted life-year (QALY) gained) was found for FSIG, followed by FIT euro 1696) and gFOBT (euro 4428); gFOBT was dominated. Compared with FSIG, FIT was associated with greater gains in QALYs and reductions in lifetime cancer incidence and mortality, but was more costly, required considerably more colonoscopies and resulted in more complications. Results were robust to variations in parameter estimates.

CONCLUSION

Population-based screening based on FIT is expected to result in greater health gains than a policy of gFOBT (with reflex FIT) or once-only FSIG, but would require significantly more colonoscopy resources and result in more individuals experiencing adverse effects. Weighing these advantages and disadvantages presents a considerable challenge to policy makers.

Factors influencing colorectal cancer screening participation

Colorectal cancer (CRC) is a major health problem worldwide. Although population-based CRC screening is strongly recommended in average-risk population, compliance rates are still far from the desirable rates. High levels of screening uptake are necessary for the success of any screening program. Therefore, the investigation of factors influencing participation is crucial prior to design and launches a population-based organized screening campaign. Several studies have identified screening behaviour factors related to potential participants, providers, or health care system. These influencing factors can also be classified in non-modifiable (i.e., demographic factors, education, health insurance, or income) and modifiable factors (i.e., knowledge about CRC and screening, patient and provider attitudes or structural barriers for screening). Modifiable determinants are of great interest as they are plausible targets for interventions. Interventions at different levels (patient, providers or health care system) have been tested across the studies with different results. This paper analyzes factors related to CRC screening behaviour and potential interventions designed to improve screening uptake.

Feasibility and efficacy of pairing fecal immunochemical testing with mammography for increasing colorectal cancer screening among uninsured Latinas in northern Manhattan

OBJECTIVES

We evaluated the feasibility and efficacy of a program to promote colorectal cancer screening (CRC) among uninsured Latinas receiving mammography through a cancer screening clinic in northern Manhattan.

METHODS

Between August 2009 and March 2010, unscreened, average CRC risk, uninsured Latinas, aged 50-64 years, undergoing mammography received a screening recommendation, education, and fecal immunochemical test (FIT). Socio-demographic information and level of acculturation was collected. Screening compliance was assessed.

RESULTS

Of 651 Latinas evaluated, 210 were eligible and, of these, 94% (n=197) consented to participate; 441 were excluded because they were up-to-date with CRC screening (n=130), < 50 (n=285) or >64 (n=26) years of age. After intervention, 177 (90%) completed FIT. Within 2 weeks, 87% completed the FIT, and 69% did so with no reminder calls. Acculturation was significantly lower among screeners (p=0.014). Compared with non-screeners, screeners were more likely to be foreign-born (p=0.009), to speak only Spanish (p=0.043), and to prefer to read (p=0.037), and think (p=0.015) in Spanish.

CONCLUSION

This study suggests that pairing CRC education and screening with mammography is both feasible and efficacious.

How to enhance physician and public acceptance and utilisation of colon cancer screening recommendations

Colorectal Cancer (CRC) screening delivery is a multidisciplinary undertaking, aiming at reducing mortality from and incidence of CRC without adversely affecting the health status of participants. The adoption of a public health perspective involves commitment to ensure equity of access and sustainability of the program over time. We reviewed available evidence concerning predictors of CRC screening uptake and the impact of interventions to improve adoption of screening using conceptual frameworks defining the role of determinants of preventive behaviours and the reach and target of interventions. The results of this review indicate that policy measures aimed at supporting screening delivery, as well as organisational changes, influencing the operational features of preventive services, need to be implemented, in order to allow individual's motivation to be eventually realised. To ensure coverage and equity of access and to maximise the impact of the intervention, policies aimed at implementing organised programs should be adopted, ensuring that participation in screening and any follow-up assessment should not be limited by financial barriers. Participants and providers beliefs may determine the response to different screening modalities. To achieve the desired health impact, an active follow-up of people with screening abnormalities should be implemented, supported by the introduction of infrastructural changes and multidisciplinary team work, which can ensure sustainability over time of effective interventions. Continuous monitoring as well as the adoption of plans to evaluate for program effectiveness represent crucial steps in the implementation of a successful program.

Endorsement by the primary care practitioner consistently improves participation in screening for colorectal cancer: a longitudinal analysis

OBJECTIVES

To investigate the effect of general practice (GP) and general practitioner (GPR) endorsement for faecal occult blood test (FOBT)-based screening on maintenance of participation in screening over four successive screening rounds.

SETTING

South Australian residents aged > or = 50 years.

METHODS

Random selection of four groups (n = 600 per group): one from the Commonwealth electoral roll (ER) and three from the combined patient lists of two collaborating GPs (GP1, GP2, GP3). Subjects were mailed offers to screen using a faecal immunochemical test over four successive rounds, spaced approximately 18 months apart. The GP1 and ER groups were invited to screen without any endorsement from a GPR or medical practice; GP2 invitees received an invitation indicating support for screening from their medical practice; and GP3 invitations were printed on practice letterhead and were signed by a GPR.

RESULTS

Multivariate analyses indicated that initial participation as well as re-participation over four successive rounds was significantly enhanced in the GP2 (39%, 42%, 45% and 44%) and GP3 groups (42%, 47%, 48% and 49%) relative to the ER group (33%, 37%, 40% and 36%). The analyses also indicated that 60-69 year olds were most likely to participate in all rounds (relative risk [RR] 1.49, 1.39, 1.43 and 1.25), and men were generally less likely to participate than women in all screening rounds (RR 0.86, 0.84, 0.80 and 0.83).

CONCLUSIONS

Associating a GPR or medical practice of recent contact with an invitation to screen achieves better participation and re-participation than does an invitation from a centralized screening unit. Furthermore, enhanced participation can be achieved by practice endorsement alone without requiring actual GPR involvement.

Comparison of immunochemical and guaiac-based fecal occult blood test in screening and surveillance for advanced colorectal neoplasms: a meta-analysis

OBJECTIVE

To systematically evaluate whether immunochemical fecal occult blood tests (iFOBT) could improve clinical performance and test accuracy in screening and surveillance for advanced colorectal neoplasms.

METHODS

Eligible articles were identified by searches of electronic databases. All randomized trials and diagnostic cohort trials directly comparing iFOBT with guaiac-based FOBT (gFOBT) were included. A statistical analysis was performed using RevMan 4.2.8. A sensitivity, specificity and summary receiver operating characteristic curve was performed using Meta Disc.

RESULTS

We identified five randomized trials and 11 diagnostic cohort trials. In the randomized trials, the detection rates of advanced colorectal neoplasms with iFOBT or gFOBT were 2.23 percent and 1.24 percent, respectively. The pooled odds ratio (OR) was 1.50 (95% CI 0.94-2.39). In cohort trials, the advanced neoplasm detection rates of iFOBT or gFOBT were 1.44 percent and 0.50 percent (OR 1.99, 95% CI 1.24-3.19) in the average-risk screened population, and were 8.8 percent and 7.1 percent (OR 1.27, 95% CI 1.01-1.60) in diagnosed patients scheduled for colonoscopy. The sensitivity of iFOBT (0.67, 95% CI 0.61-0.73) was superior to that of gFOBT (0.54, 95% CI 0.48-0.60), as well as the specificities (0.85, 95% CI 0.83-0.87 vs 0.80, 95% CI 0.78-0.82) and positive predictive values (0.41 vs 0.29) in cohort trials of diagnosed patients.

CONCLUSION

Our review suggests that iFOBT could perform better in increasing the detection rate of advanced colorectal neoplasm than gFOBT and possesses higher sensitivity and specificity in the surveillance of advanced colorectal neoplasm for patients.

Population-based screening for colorectal cancer: Australian research and implementation

Australia is one of the first countries in the world to implement an organized whole-of-population screening program for colorectal cancer (CRC). Australians have made broad contributions to CRC in general ranging from primary prevention through genetics, secondary prevention and treatment, to palliation. This overview focuses on some of the contributions of direct relevance to population-based screening, stretching from technology development to population-based controlled studies and health services research. In terms of simple screening tests in a two-step screening strategy, the evidence is overwhelming that fecal immunochemical tests for hemoglobin (FITs) improve detection and are more acceptable. FIT-based screening is clearly acceptable to Australians and it has been demonstrated that a national organized screening program is feasible. In terms of benefit for Australians, with full roll out and high uptake by the population we could see the number of cases dying from CRC halved by this strategy. To this will be added the extra-screening benefits of improved diagnosis, improved treatment and improved public awareness, all benefits of other screening programs. CRC screening has progressed from a matter of irrelevance and distaste, to commonwealth government policy in the context of an organized program for all Australians.

[Influence of the pre-analytical specimen storage conditions on the fecal occult blood test results]

BACKGROUND

Korean national cancer screening program selected fecal occult blood test (FOBT) as a primary screening method of colorectal carcinoma in adult > or =50 yr old irrespective of symptom. Notice to pre-analytical errors is especially important for the FOBT because examinees collect and submit their specimens to laboratories by themselves. We examined the influences of the fecal storage temperatures, durations and with or without buffer on the FOBT results.

METHODS

Thirty FOBT-positive specimens above 100 ng/mL were used for the study from July to August 2008. Quantitative FOBT was performed with OC-sensors II (Eiken Chemical Co., Japan). Each specimen was divided into 4 groups. Two groups in plastic buffer-free containers were kept either at 4 degrees C or room temperature (25-28 degrees C), respectively. Another two groups in buffer-tubes were also kept either at 4 degrees C or room temperature. Each group was repeatedly examined with same method every 24 hr up to 120 hr.

RESULTS

Eleven specimens (36.7%) in buffer-free containers converted to negative results (below the 100 ng/mL) after 24 hr and 17 specimens (56.7%) did after 48 hr at room temperature. Ten specimens (33.3%) in buffer-free containers converted to negative after 48 hr at 4 degrees C. Specimens contained in buffer-tubes showed little change; 3 specimens (10.0%) at room temperature and no specimen at 4 degrees C showed negative conversions after 48 hr.

CONCLUSIONS

Buffer-tube minimizes false negative FOBT results during pre-analytical delay of specimen. The examinees using buffer-free containers need to be educated to hand in their specimens to laboratories as soon as possible.

[Improvement in screening for colorectal cancer associated with the use of immunochemical faecal occult blood test]

Faecal occult blood tests (FOBT) have been established as the most relevant procedure for colorectal cancer screening in the general average risk population. Immunochemical FOBT consists in monoclonal antibodies reacting with the globin of the haemoglobin. These tests provide higher performances than traditional guaiac tests. They do not need any diet restriction and their analytic sensitivity is higher. An increasing number of papers suggest that their acceptance and clinical performances in the general population are more satisfactory than the guaiac test. The use of automated reading allowed to cut the process price making it similar to the guaiac test. The providing of quantitative measure of haemoglobin allows to choose the positivity threshold associated with the best balance between sensitivity, specificity and positivity rate. Comparative studies conducted in France suggest the use of a positivity threshold allowing an increase in both sensitivity and specificity compared to the guaiac tests.

Nicht-invasive Diagnostik kolorektaler Tumore – Hat der Guaiac-Test ausgedient? / Non-invasive detection of colorectal cancer – do we still need the guaiac-based fecal occult blood test?

Aufgrund der leichten Handhabung und des Nachweises einer Mortalitätssenkung gilt der Nachweis von okkultem Blut (FOBT) im Stuhl derzeit als das am weitesten verbreitete Screeningverfahren für das kolorektale Karzinom. Als nachteilig erweisen sich allerdings eine unzureichende Sensitivität, insbesondere beim Nachweis früher Stadien und eine nach wie vor geringe Akzeptanz in der Bevölkerung. Vorläufige Daten zum Nachweis von Calprotectin oder der Tumor-M2-PK im Stuhl ließen bessere Screeningeigenschaften erwarten. Aber auch hier schränkt die geringe Sensitivität für frühe Vorstufen und unzureichende Spezifität mit zu erwartenden hohen Folgekosten die Tauglichkeit der Tests deutlich ein. Die kürzlich entwickelten immunologischen FOBTs (I-FOBT) erweisen sich als spezifischer und sensitiver. Sie beruhen auf dem Nachweis von humanem Hämoglobin mittels spezifischer Antikörper und sind somit unabhängig von diätetischen oder medikamentösen Faktoren, was zu einer deutlich besseren Akzeptanz führt. Sie gelten derzeit als kosteneffektivste Verfahren unter den nichtinvasiven Screeningmaßnahmen. Der Nachweis von Tumor-DNA im Stuhl eröffnet eine neue Ära zum frühzeitigen Nachweis kolorektaler Karzinome. Erste kleinere Studien weisen auf eine sehr gute Sensitivität dieser Verfahren hin. Sie lagen für kolorektale Karzinome zwischen 62–91% und für Adenome zwischen 26–73% bei mit 93–100% sehr guter Spezifität. Als nachteilig im Vergleich zu den derzeit verfügbaren Screeningtests erweisen sich allerdings die vergleichsweise hohen Kosten.

Guaiac versus immunochemical tests: faecal occult blood test screening for colorectal cancer in a rural community

OBJECTIVE

To describe patient participation and clinical performance in a colorectal cancer (CRC) screening program utilising faecal occult blood test (FOBT).

METHODS

A community-based intervention was conducted in a small, rural community in north Queensland, 2000/01. One of two FOBT kits--guaiac (Hemoccult-II) or immunochemical (!nform)--was assigned by general practice and mailed to participants (3,358 patients aged 50-74 years listed with the local practices).

RESULTS

Overall participation in FOBT screening was 36.3%. Participation was higher with the immunochemical kit than the guaiac kit (OR=1.9, 95% CI 1.6-2.2). Women were more likely to comply with testing than men (OR=1.4, 95% CI 1.2-1.7), and people in their 60s were less likely to participate than those 70-74 years (OR=0.8, 95% CI 0.6-0.9). The positivity rate was higher for the immunochemical (9.5%) than the guaiac (3.9%) test (chi2=9.2, p=0.002), with positive predictive values for cancer or adenoma of advanced pathology of 37.8% (95% CI 28.1-48.6) for !nform and 40.0% (95% CI 16.8-68.7) for Hemoccult-II. Colonoscopy follow-up was 94.8% with a medical complication rate of 2-3%.

CONCLUSIONS

An immunochemical FOBT enhanced participation. Higher positivity rates for this kit did not translate into higher false-positive rates, and both test types resulted in a high yield of neoplasia.

IMPLICATIONS

In addition to type of FOBT, the ultimate success of a population-based screening program for CRC using FOBT will depend on appropriate education of health professionals and the public as well as significant investment in medical infrastructure for colonoscopy follow-up.

Influences on participation in a community-based colorectal neoplasia screening program by virtual colonoscopy in Australia

OBJECTIVE

To determine the effect of certain personal and health behaviour characteristics on participation in a community-based colorectal neoplasia (CRN) screening program using virtual colonoscopy.

METHODS

The study population comprised randomly selected subjects from the State electoral roll; screening by virtual colonoscopy was offered through letter of invitation. For non-responders, a further invitation was sent a month later. Non-response after a further month led to subjects being considered non-participants. Non-participants were contacted by letter to complete a structured questionnaire; participants completed a similar questionnaire immediately after their screening virtual colonoscopy.

RESULTS

Discussing the invitation to screening with someone else increased the likelihood of participation by 63% (prevalence ratio 1.63, 95% CI 1.38-1.93); knowing someone with cancer increased the likelihood of participation by 23% (PR 1.23, 95% CI 1.07-1.42). Among participants who discussed screening with another individual, the spouse was the most common (71%). Subjects who were single were less likely to participate (PR 0.79, 95% CI 0.67-0.94). The strongest reported influence for participation was information provided in the letter of invitation (29.8%). The most common reasons for non-participation were lack of time and perceived good health.

CONCLUSIONS AND IMPLICATIONS

This study suggests that a simple strategy to facilitate participation is to encourage subjects to discuss screening with others; further, to recognise that this may be most difficult for those who are single. Information provided to subjects prior to screening positively contributes to participation.

Comparison of a brush-sampling fecal immunochemical test for hemoglobin with a sensitive guaiac-based fecal occult blood test in detection of colorectal neoplasia

BACKGROUND

Fecal immunochemical tests (FIT) are an advanced fecal occult blood test (FOBT) technology that reduces barriers to population screening by simplifying the logistics of stool-sampling. The current study was conducted to undertake a paired comparison of a sensitive guaiac FOBT (GFOBT; Hemoccult II Sensa, Beckman Coulter, Fullerton, CA) with a brush-sampling FIT (InSure; Enterix, North Ryde, NSW, Australia), to determine whether this FIT improves detection of significant neoplasia.

METHODS

Individuals sampled consecutive stools, at home, with both FIT and GFOBT sampling devices while following dietary restrictions appropriate for GFOBT. Study populations included a screening cohort (n = 2351) and a symptomatic diagnostic group (n = 161). Paired comparison of positivity rates was undertaken in those found to have cancer and/or significant adenoma (high-grade dysplasia, villous change, > or =10 mm, serrated histology or > or =3 polyps), benign pathology, or no pathology.

RESULTS

Combined results for both cohorts showed that the FIT returned a true-positive result significantly more often in cancer (n = 24; 87.5% vs. 54.2%) and in significant adenomas (n = 61; 42.6% vs. 23.0%). Of all UICC Stage I cancers, the FIT was positive in 12 of 13 compared with 4 of 13 with the GFOBT (P = .002). In analyses of just the screening cohort, the FIT remained significantly better at detecting cancers and significant adenomas; the false-positive rate for any neoplasia was marginally higher with the FIT than the GFOBT (3.4% vs. 2.5%; 95% CI of difference, 0-1.8%), whereas positive predictive values were 41.9% and 40.4%, respectively.

CONCLUSIONS

This brush-sampling FIT is more sensitive for cancers and significant adenomas than a sensitive GFOBT. As such, it should deliver greater reductions in colorectal cancer mortality and incidence than the GFOBT.

Screening for colorectal cancer in average-risk populations

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

The role of GPs in increasing compliance to colorectal cancer screening: a randomised controlled trial (Italy)

AIMS

To assess the effect of the provider (GPs versus hospital) on the compliance in returning the faecal occult blood test. To analyse the characteristics of the GP associated with high compliance among his beneficiaries.

METHODS

A questionnaire about screening attitudes was mailed to the 1192 GPs working in 13 districts of the Lazio region. We asked the GPs to participate in a randomised trial, we sampled 130 GPs and about 1/10 of the GPs' 50-75 year old beneficiaries (n = 3657) were invited to be screened at the GP office and 1/10 (3675) at the nearest gastroenterology centre.

RESULTS

58.5% of the GPs completed the questionnaire and 22.7% agreed to participate in the trial. The compliance in the GP arm was 50%, in the hospital arm 16% (RR 3.4; 95% CI: 3.13-3.70). There was a high variability in the compliance obtained by the GPs. GPs with more than 25 patients visited/day and those incorrectly recommended screening of colorectal cancer obtained a lower compliance (OR 0.74, 95% CI: 0.57-0.95 and OR 0.76, 95% CI: 0.59-0.97, respectively).

CONCLUSIONS

The involvement of GPs in colorectal cancer screening can be very effective to enhance the compliance, but the effectiveness is dependent on their willingness to be involved.

From guaiac to immune fecal occult blood tests: the emergence of technology in colorectal cancer screening

Colorectal cancer is the second leading cause of cancer deaths in the United States for both men and women. Colorectal cancer screening is an important means for reducing morbidity and mortality. The American Cancer Society recommends five different screening regimens for adults of average risk, age 50 years and older. The optimal effectiveness of a screening program is dependent on the accuracy of the screening test used. An accurate screening test would have high sensitivity (positive) when an adenomatous polyp or cancer is present and high specificity (negative) in their absence. In April 2002, the American Cancer Society Colorectal Cancer Advisory Group concluded that the immunochemical fecal occult blood test has some advantages that merit revision of their guideline statement for fecal occult blood testing, to include the immunochemical fecal occult blood test. The advantages cited were the possibility of improved sensitivity and specificity and the lack of required dietary restrictions, which make it a more patient-friendly test. Several types of immunochemical fecal occult blood tests are discussed in this article, including their advantages and disadvantages compared with those of the traditional guaiac fecal occult blood testing.

Noninvasive testing for colorectal cancer: a review

OBJECTIVES

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Endoscopic screening is now in favor and its use is increasing, but overall participation rates are poor. A substantial percentage of the population will likely continue to resist endoscopic screening. As such, a noninvasive biomarker for the early detection of CRC remains a priority. Herein, we (i) review the currently available noninvasive screening markers for the early detection of CRC, (ii) discuss newer markers that have undergone preliminary testing, and (iii) introduce and explain potentially promising markers of the future.

METHODS

The published literature on markers for early detection of CRC was identified using a MEDLINE/PubMed search with secondary review of cited publications.

RESULTS

Noninvasive testing for CRC is most advanced in testing for stool fecal occult blood, globin, or DNA mutations. Study of abnormal mucins has also been explored. Research for serum-based markers is just beginning and includes serum proteomics, nuclear matrix proteins, and serum DNA testing.

CONCLUSIONS

Serial guaiac-based fecal occult blood testing (FOBT) is simple, inexpensive, and proven effective at reducing mortality from CRC. Immunochemical fecal occult blood tests facilitate compliance and offer improved specificity, but at increased cost in comparison to FOBT. Fecal DNA testing may provide enhanced sensitivity for detection of CRC in comparison with FOBT, but its high cost limits its use for generalized screening. Rectal mucin testing requires additional evaluation to determine its sensitivity and specificity in comparison with guaiac-based FOBT. Serum tests, such as proteomics, nuclear matrix proteins, and serum DNA, are still in their infancy, but remain a hope for the future.

The stool DNA test: an emerging technology in colorectal cancer screening

The stool DNA test is considered an emerging technology in screening for colorectal cancer. The stool DNA test detects DNA markers which are shed from cells of premalignant adenomas and cancers into the stool. Potentially, both preclinical and clinical colorectal cancer may be detected. Panels of multiple DNA markers are used to ensure a high sensitivity for colorectal cancer. In this article, several advantages of the stool DNA test (compared with current colorectal cancer screening methods) are discussed. The stool DNA test may be more patient-friendly and has a higher degree of sensitivity and specificity for colorectal cancer. No bowel or dietary preparation is required and the test is noninvasive. The stool DNA test screens the entire colon and may detect some other types of cancers proximal to the colon. In the future, there may be potential to use the stool DNA test to screen for aerodigestive cancers (lung, esophageal, gastric, and pancreatic), in addition to colorectal cancer. An improved noninvasive screening test would help allocate colonoscopy resources to those patients who would benefit the most. Colorectal cancer screening cost-effectiveness may also be improved. Some limitations of the stool DNA test include the need for clinical studies in average-risk populations and marker refinement. An automated testing system may help reduce costs and turnaround times. Despite recognized limitations, the stool DNA test is a promising new diagnostic tool with the potential to improve effectiveness of colorectal cancer screening.

Colorectal cancer screening: prospects for molecular stool analysis

Colorectal cancer is common. As many patients present with advanced disease, an effective screening test would have substantial clinical benefits. Recent progress in understanding the biology of colorectal cancer (and of cancer cells in general) has led to possible new approaches to screening. In particular, there are prospects of developing tests based on analysis of stool, which promise improved accuracy, safety, affordability and patient compliance.

The view from two sides: a qualitative study of community and medical perspectives on screening for colorectal cancer using FOBT

BACKGROUND

Population-wide screening for people at average risk of colorectal cancer (CRC) by faecal occult blood test (FOBT) is under consideration in Australia.

METHODS

Qualitative methods were used to examine the views of community members who did (n = 18) or did not (n = 12) participate in a pilot program of FOBT screening. In addition, views were obtained from general practitioners (GPs) and specialist gastroenterologists directly involved in the implementation of the program. Two focus group sessions were conducted with screening participants and interviews were conducted with nonparticipants, GPs and gastroenterologists.

RESULTS

The findings suggest that CRC screening by FOBT distributed to households by mail was well accepted by the community and by the medical practitioners involved in its implementation. The trial had little negative effect on general practice. Both medical practitioners and consumers raised concerns about the efficacy of FOBT screening. Medical practitioners were also concerned about the potential burden mass screening could place on the public (government-funded) health care sector.

CONCLUSIONS

It would seem that CRC screening using FOBT will not enjoy unqualified support from the community or from medical practitioners involved in the continuum of screening. Information about the objectives of screening programs, in general, and the efficacy of FOBT screening in particular, needs to be provided to the community to ensure informed individual choice.

The evolution to stool DNA testing for colorectal cancer

Despite a variety of screening strategies and recent trends showing death rate stabilization, colorectal cancer still remains the second leading cause of overall cancer death. Current screening tools suffer from performance limitations, low patient acceptability, and marginal reliable access within the health care system. Noninvasive strategies present the lowest risk with the highest potential for patient satisfaction. However, serious implementation barriers exist requiring consistent programmatic screening, strict patient adherence, and poor sensitivity for adenomas. Colonoscopy remains an invasive screening test with the best sensitivity and specificity, but faces large financial costs, manpower requirements, patient access and adherence. Development of advanced molecular techniques identifying altered DNA markers in exfoliated colonocytes signify early or precancerous growth. Stool-based DNA testing provides an entirely noninvasive population-based screening strategy which patients can perform easier than faecal occult blood testing (FOBT). Large-scale prospective randomized control trials currently pending should help characterize accurate test performance, screening intervals, cost-effectiveness, direct comparison to FOBT and analysis of patient adherence. As tumour development pathways and potential target genes are further elucidated, refinements in multi-assay stool-based DNA testing portend enhanced test characteristics to detect and treat this genetically heterogeneous disease.

Preventing cancer: dietary lifestyle or clinical intervention?

In Australia, colorectal, prostate and breast cancers are the most frequently occurring cancers in our society, a pattern that is quite different from that of underdeveloped countries. While diet is largely responsible for these differences, technological advances mean that the solutions can be viewed as systematic, financial, lifestyle or technological. They range from those that require self-discipline and care for personal well-being through to those that are seemingly a quick technological fix that will work in spite of an unhealthy lifestyle. There are three main approaches available for prevention of these cancers: dietary lifestyle, chemoprevention and screening. It has been estimated that the potential for prevention by a healthy dietary lifestyle is excellent and might reduce the burden of breast, prostate and colorectal cancer by 33-55%, 10-20% and 66-75%, respectively. This should be safe and inexpensive and have collateral benefit such as reduced cardiovascular disease and osteoporosis. But, population compliance with more plant-based, less calorie dense foods is uncertain, the most healthy are likely to be the most compliant and evidence for effectiveness when interventional programs are undertaken is disappointing. It is not clear how dependable the dietary approach would be where inherited genetic factors determine risk for one of these cancers. Chemoprevention, the administration of natural or synthetic agents that delay, slow down or inhibit the process of tumorigenesis, are still under development and study. Hormone receptor modulators for breast and derivatives of non-steroidal anti-inflammatory drugs for colorectal cancers seem to have most promise and may reduce tumour incidence or death by as much as 50%. These agents are simpler to comply with than changing dietary lifestyle and they are more potent, hence they may be of particular value in high-risk settings. But they are likely to be more costly and run the risk of adverse effects with few collateral benefits. Screening, or the testing of an individual for a disease when that individual does not have any symptoms or signs suggesting that the disease is present, aims to prevent or delay the development of the cancer. Screening impacts on mortality more so than on incidence, reducing colorectal cancer mortality in the range 15-60% and breast cancer mortality by 23-37%. Screening has the advantage of being effective in high-risk as well as average-risk groups and is an 'easy' solution for the person who elects not to follow a healthy dietary lifestyle. Nonetheless, it is expensive, demanding on resources, provides no collateral benefits and does not have the same potential to reduce incidence of disease as does the dietary approach. With these Western cancers, we are fortunate that there are options for prevention. At least choices are available and some will suite certain circumstances and personalities more than others.

Measuring the importance of attributes that influence consumer attitudes to colorectal cancer screening

BACKGROUND

The aim of the present study was to rate the importance of attributes of screening for bowel cancer.

METHOD

Randomly selected households in central Sydney were contacted to identify men and women aged 50-70 years who were then asked to complete a self-administered questionnaire about bowel cancer screening and related issues. Seven hundred and ninety-one residents (362 men and 429 women) returned questionnaires. Respondents were asked to rate the extent to which each of 34 attributes would encourage them to participate in bowel cancer screening.

RESULTS

The three most highly rated attributes were: if the test was recommended by their general practitioner (GP; 94% either 'strongly agreed' or 'agreed'); if the test identified early cancers (92%); and if the test would avert a premature death due to bowel cancer (90%). Having a friend or relative with bowel cancer (61%), advertising (41%) or famous people promoting the program (62%) were less influential. Respondents who were unemployed or on a pension were less likely to participate in screening than those who were employed if there was an 'out of pocket' charge of 15.00 Australian dollars (chi 2 = 7.56, 2df, P = 0.006). Respondents with higher levels of education were significantly more concerned than respondents with lower levels of education about test accuracy (chi 2 = 15.76, 2df, P < 0.001), its availability from their local chemist (chi 2 = 16.96, 2df, P < 0.001), being able to return the test kit by post (chi 2 = 21.9, 2df, P < 0.001) or deposit it with their local chemist (chi 2 = 10.0, 2df, P < 0.01). They were also less likely to be influenced by a famous person promoting bowel cancer screening (chi 2 = 18.87, 2df, P < 0.001).

CONCLUSIONS

Our results endorse the role of the GP in bowel cancer screening. However, the study also has demonstrated that test accuracy, the convenience of the screening service and notification of test results are valued differently by subgroups in the community, according to their level of education.