Comparative economic evaluation of data from the ACRIN National CT Colonography Trial with three cancer intervention and surveillance modeling network microsimulations

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.

Modeling the Natural History and Screening Effects of Colorectal Cancer Using Both Adenoma and Serrated Neoplasia Pathways: The Development, Calibration, and Validation of a Discrete Event Simulation Model

Background. Existing colorectal cancer (CRC) screening models mostly focus on the adenoma pathway of CRC development, overlooking the serrated neoplasia pathway, which might result in overly optimistic screening predictions. In addition, Bayesian inference methods have not been widely used for model calibration. We aimed to develop a CRC screening model accounting for both pathways, calibrate it with approximate Bayesian computation (ABC) methods, and validate it with large CRC screening trials. Methods. A discrete event simulation (DES) of the CRC natural history (DECAS) was constructed using the adenoma and serrated pathways in R software. The model simulates CRC-related events in a specific birth cohort through various natural history states. Calibration took advantage of 74 prevalence data points from the German screening colonoscopy program of 5.2 million average-risk participants using an ABC method. CRC incidence outputs from DECAS were validated with the German national cancer registry data; screening effects were validated using 17-y data from the UK Flexible Sigmoidoscopy Screening sigmoidoscopy trial and a German screening colonoscopy cohort study. Results. The Bayesian calibration rendered 1,000 sets of posterior parameter samples. With the calibrated parameters, the observed age- and sex-specific CRC prevalences from the German registries were within the 95% DECAS-predicted intervals. Regarding screening effects, DECAS predicted a 41% (95% intervals 30%-51%) and 62% (95% intervals 55%-68%) reduction in 17-y cumulative CRC mortality for a single screening sigmoidoscopy and colonoscopy, respectively, falling within 95% confidence intervals reported in the 2 clinical studies used for validation. Conclusions. We presented DECAS, the first Bayesian-calibrated DES model for CRC natural history and screening, accounting for 2 CRC tumorigenesis pathways. The validated model can serve as a valid tool to evaluate the (cost-)effectiveness of CRC screening strategies.

Highlights

This article presents a new discrete event simulation model, DECAS, which models both adenoma-carcinoma and serrated neoplasia pathways for colorectal cancer (CRC) development and CRC screening effects.DECAS is calibrated based on a Bayesian inference method using the data from German screening colonoscopy program, which consists of more than 5 million first-time average-risk participants aged 55 years and older in 2003 to 2014.DECAS is flexible for evaluating various CRC screening strategies and can differentiate screening effects in different parts of the colon.DECAS is validated with large screening sigmoidoscopy and colonoscopy clinical study data and can be further used to evaluate the (cost-)effectiveness of German colorectal cancer screening strategies.

Cost Effectiveness of Mailed Outreach Programs for Colorectal Cancer Screening: Analysis of a Pragmatic, Randomized Trial

BACKGROUND & AIMS

Clinical guidelines for colorectal cancer (CRC) screening suggest use of either stool-based tests or colonoscopy - modalities that differ in recommended screening intervals, adherence, and costs. We know little about the long-term cost differences in population-health outreach strategies to promote these strategies.

METHODS

We conducted a cost-effectiveness analysis to compare 2 mailed outreach strategies to increase CRC screening from a pragmatic, randomized clinical trial: mailed fecal immunochemical test (FIT) kits vs invitations to complete a screening colonoscopy. We built a 10-year Markov chain Monte Carlo microsimulation model to account for differences in screening intervals, adherence, and costs.

RESULTS

Mailed FIT kits had a lower 10-year average per-person cost of screening relative to colonoscopy invitations ($1139 vs $1725) but with 10.89 fewer months of compliance and 60 fewer advanced neoplasia detected (37 advanced adenomas and 23 CRC). Incremental cost effectiveness ratios for colonoscopy invitations compared with mailed FIT kits were $55.23, $15.84, and $25.48 per additional covered month, advanced adenoma, and CRC, respectively. Although FIT was the preferred strategy at low willingness-to-pay thresholds, the 2 strategies were equal at a willingness-to-pay threshold of $41.31 per covered month gained.

CONCLUSION

Mailed FIT or colonoscopy invitations are both options to improve CRC screening completion and advanced neoplasia detection, and the choice of outreach strategy may differ by a health system's willingness-to-pay threshold. Mailed FIT kits are less expensive than colonoscopy invitations but result in fewer months of screening compliance and advanced neoplasia detected.

Estimating the impact of differential adherence on the comparative effectiveness of stool-based colorectal cancer screening using the CRC-AIM microsimulation model

BACKGROUND

Real-world adherence to colorectal cancer (CRC) screening strategies is imperfect. The CRC-AIM microsimulation model was used to estimate the impact of imperfect adherence on the relative benefits and burdens of guideline-endorsed, stool-based screening strategies.

METHODS

Predicted outcomes of multi-target stool DNA (mt-sDNA), fecal immunochemical tests (FIT), and high-sensitivity guaiac-based fecal occult blood tests (HSgFOBT) were simulated for 40-year-olds free of diagnosed CRC. For robustness, imperfect adherence was incorporated in multiple ways and with extensive sensitivity analysis. Analysis 1 assumed adherence from 0%-100%, in 10% increments. Analysis 2 longitudinally applied real-world first-round differential adherence rates (base-case imperfect rates = 40% annual FIT vs 34% annual HSgFOBT vs 70% triennial mt-sDNA). Analysis 3 randomly assigned individuals to receive 1, 5, or 9 lifetime (9 = 100% adherence) mt-sDNA tests and 1, 5, or 9 to 26 (26 = 100% adherence) FIT tests. Outcomes are reported per 1000 individuals compared with no screening.

RESULTS

Each screening strategy decreased CRC incidence and mortality versus no screening. In individuals screened between ages 50-75 and adherence ranging from 10%a-100%, the life-years gained (LYG) for triennial mt-sDNA ranged from 133.1-300.0, for annual FIT from 96.3-318.1, and for annual HSgFOBT from 99.8-320.6. At base-case imperfect adherence rates, mt-sDNA resulted in 19.1% more LYG versus FIT, 25.4% more LYG versus HSgFOBT, and generally had preferable efficiency ratios while offering the most LYG. Completion of at least 21 FIT tests is needed to reach approximately the same LYG achieved with 9 mt-sDNA tests.

CONCLUSIONS

Adherence assumptions affect the conclusions of CRC screening microsimulations that are used to inform CRC screening guidelines. LYG from FIT and HSgFOBT are more sensitive to changes in adherence assumptions than mt-sDNA because they require more tests be completed for equivalent benefit. At imperfect adherence rates, mt-sDNA provides more LYG than FIT or HSgFOBT at an acceptable tradeoff in screening burden.

Promoting colorectal cancer screening: a systematic review and meta-analysis of randomised controlled trials of interventions to increase uptake

Colorectal cancer (CRC) represents a global public health concern. CRC screening is associated with significant reductions in CRC incidence and mortality, however, uptake is suboptimal. This systematic review and meta-analysis of randomised controlled trials explored the effectiveness of interventions designed to increase screening uptake, plus the impact of various moderators. Data from 102 studies including 1.94 million participants were analysed. Results showed significant benefit of all interventions combined (OR, 1.49, 95% CI: 1.43, 1.56, p < 0.001). The effects were similar in studies using objective versus self-reported uptake measures and lower in studies judged to be at high risk of bias. Moderator analyses indicated significant effects for aspects of behaviour (effects lower for studies on non-endoscopic procedures), and intervention (effects higher for studies conducted in community settings, in healthcare systems that are not free, and that use reminders, health-professional providers, paper materials supplemented with in-person or phone contact, but avoid remote contact). Interventions that included behaviour change techniques targeting social support (unspecified or practical), instructions or demonstration of the behaviour, and that added objects to the environment produced stronger effects. The way in which findings can inform interventions to improve CRC screening uptake is discussed.

Cost-Effectiveness of Colorectal Cancer Screening Strategies-A Systematic Review

BACKGROUND & AIMS

Widespread screening for colorectal cancer (CRC) has reduced its incidence and mortality. Previous studies investigated the economic effects of CRC screening. We performed a systematic review to provide up-to-date evidence of the cost effectiveness of CRC screening strategies by answering 3 research questions.

METHODS

We searched PubMed, National Institute for Health Research Economic Evaluation Database, Social Sciences Citation Index (via the Web of Science), EconLit (American Economic Association) and 3 supplemental databases for original articles published in English from January 2010 through December 2017. All monetary values were converted to US dollars (year 2016). For all research questions, we extracted, or calculated (if necessary), per-person costs and life years (LYs) and/or quality-adjusted LYs, as well as the incremental costs per LY gained or quality-adjusted LY gained compared with the baseline strategy. A cost-saving strategy was defined as one that was less costly and equally or more effective than the baseline strategy. The net monetary benefit approach was used to answer research question 2.

RESULTS

Our review comprised 33 studies (17 from Europe, 11 from North America, 4 from Asia, and 1 from Australia). Annual and biennial guaiac-based fecal occult blood tests, annual and biennial fecal immunochemical tests, colonoscopy every 10 years, and flexible sigmoidoscopy every 5 years were cost effective (even cost saving in most US models) compared to no screening. In addition, colonoscopy every 10 years was less costly and/or more effective than other common strategies in the United States. Newer strategies such as computed tomographic colonography, every 5 or 10 years, was cost effective compared with no screening.

CONCLUSIONS

In an updated review, we found that common CRC screening strategies and computed tomographic colonography continued to be cost effective compared to no screening. There were discrepancies among studies from different regions, which could be associated with the model types or model assumptions.

Measurement of the IgM and IgG Autoantibody Immune Responses in Human Serum has High Predictive Value for the Presence of Colorectal Cancer

INTRODUCTION

Colorectal cancer is a major public health issue, with incidences continuing to rise owing to the growing and aging world population. Current screening strategies for colorectal cancer diagnosis suffer from various limitations, including invasiveness and poor uptake. Consequently, there is an unmet clinical need for a minimally invasive, sensitive, and specific method for detecting the presence of colorectal cancer and pre-malignant lesions.

PATIENTS AND METHODS

An indirect enzyme-linked immunosorbent assay was used to measure the primary (IgM) and secondary (IgG) adaptive humoral immune responses to a panel of previously identified cancer antigens in the sera of normal and adenoma samples, and sera from patients with colorectal cancer.

RESULTS

An optimal panel of 7 biomarkers capable of identifying patients with colorectal cancer as distinct from both normal and adenoma samples is identified. The cumulative sensitivity and specificity of the assay are 70.8% and 86.5%, respectively. The positive and negative predictive values of the cohort are 77.3% and 82.1%. This assay was not able to accurately discriminate between normal and adenoma samples. Patients whose serum was positive for the presence of anti-ICLN IgM autoantibodies had a significantly poorer 5-year survival than patients whose serum was negative (P = .004).

CONCLUSION

This study describes a novel minimally invasive enzyme-linked immunosorbent assay-based method, capable of identifying patients with colorectal cancer as distinct from both normal and adenoma samples. Patients are likely to be far more amenable to a blood-based test such as the one described herein, rather than a fecal-based test, likely leading to increased patient uptake.

Cost analysis of colorectal cancer screening with CT colonography in Italy

OBJECTIVE

Unit costs of screening CT colonography (CTC) can be useful for cost-effectiveness analyses and for health care decision-making. We evaluated the unit costs of CTC as a primary screening test for colorectal cancer in the setting of a randomized trial in Italy.

METHODS

Data were collected within the randomized SAVE trial. Subjects were invited to screening CTC by mail and requested to have a pre-examination consultation. CTCs were performed with 64- and 128-slice CT scanners after reduced or full bowel preparation. Activity-based costing was used to determine unit costs per-process, per-participant to screening CTC, and per-subject with advanced neoplasia.

RESULTS

Among 5242 subjects invited to undergo screening CTC, 1312 had pre-examination consultation and 1286 ultimately underwent CTC. Among 129 subjects with a positive CTC, 126 underwent assessment colonoscopy and 67 were ultimately diagnosed with advanced neoplasia (i.e., cancer or advanced adenoma). Cost per-participant of the entire screening CTC pathway was €196.80. Average cost per-participant for the screening invitation process was €17.04 and €9.45 for the pre-examination consultation process. Average cost per-participant of the CTC execution and reading process was €146.08 and of the diagnostic assessment colonoscopy process was €24.23. Average cost per-subject with advanced neoplasia was €3777.30.

CONCLUSIONS

Cost of screening CTC was €196.80 per-participant. Our data suggest that the more relevant cost of screening CTC, amenable of intervention, is related to CTC execution and reading process.

Systematic review of colorectal cancer screening guidelines for average-risk adults: Summarizing the current global recommendations

AIM

To summarize and compare worldwide colorectal cancer (CRC) screening recommendations in order to identify similarities and disparities.

METHODS

A systematic literature search was performed using MEDLINE, EMBASE, Scopus, CENTRAL and ISI Web of knowledge identifying all average-risk CRC screening guideline publications within the last ten years and/or position statements published in the last 2 years. In addition, a hand-search of the webpages of National Gastroenterology Society websites, the National Guideline Clearinghouse, the BMJ Clinical Evidence website, Google and Google Scholar was performed.

RESULTS

Fifteen guidelines were identified. Six guidelines were published in North America, four in Europe, four in Asia and one from the World Gastroenterology Organization. The majority of guidelines recommend screening average-risk individuals between ages 50 and 75 using colonoscopy (every 10 years), or flexible sigmoidoscopy (FS, every 5 years) or fecal occult blood test (FOBT, mainly the Fecal Immunochemical Test, annually or biennially). Disparities throughout the different guidelines are found relating to the use of colonoscopy, rank order between test, screening intervals and optimal age ranges for screening.

CONCLUSION

Average risk individuals between 50 and 75 years should undergo CRC screening. Recommendations for optimal surveillance intervals, preferred tests/test cascade as well as the optimal timing when to start and stop screening differ regionally and should be considered for clinical decision making. Furthermore, local resource availability and patient preferences are important to increase CRC screening uptake, as any screening is better than none.

Cost-Effectiveness of Community Interventions for Colorectal Cancer Screening: Low-Income Hispanic Population

OBJECTIVE

To assess the cost-effectiveness of interventions to increase colorectal cancer (CRC) screening among low-income uninsured Hispanics in El Paso, Texas.

METHOD

Participants 50 to 75 years old who were due for screening, were uninsured, and had a Texas address were randomized to promotora, video, or promotora and video interventions. High-risk participants were offered colonoscopy, while others were offered fecal immunochemical testing. A nonintervention comparison group was recruited from a similar Texas U.S.-Mexico border county. Screening was determined at 6 months postintervention. Resources were tracked prospectively to determine cost. Incremental cost-effectiveness ratios were assessed with "intention to treat" methods. Uncertainty in the estimates was analyzed with sensitivity analysis and nonparametric bootstrap methods.

RESULTS

The interventions achieved screening rates of between 75% and 87% compared to 10% in the comparison group. The cost per participant ranged from $72 for group sessions to $93 for individual video sessions with video and promotora. The group video sessions cost $104 per additional person screened.

CONCLUSION

The CRC screening interventions were effective for increasing CRC screening. Compared to the experience in the control county, the group-based video-only intervention was the most cost-effective CRC screening promotion intervention.

Recent diagnostic procedures for colorectal cancer screening: Are they cost-effective?

Colorectal cancer (CRC) is the third most common cancer worldwide and the fourth most common cause of death. Reduction in mortality rates in some countries worldwide are most likely ascribed to CRC screening and/or improved treatments. We reviewed the most relevant articles which discuss the cost-effectiveness of colorectal cancer screening procedures, in particular, the recent ones through the last eight years. The effectiveness of screening estimated by discounted life years gained (LYGs) compared to no screening, differed considerably between the studies. Despite these differences, all studies consistently emphasized that screening for CRC was cost-effective compared with no screening for each of the recognized screening strategies. Newer technologies for colorectal cancer screening, including computed tomographic colonography (CTC), faecal DNA test, and Pillcam Colon are less invasive and accurate, however, they are not cost-effective, as their cost was higher than all other established screening strategies. When compliance and adherence to such new techniques are increased more than the established strategies they would be more cost-effective particularly CTC.

Screening for colorectal cancer

This review will comprise a general overview of colorectal cancer (CRC) screening. We will cover the impact of CRC, CRC risk factors, screening modalities, and guideline recommendations for screening in average-risk and high-risk individuals. Based on this data, we will summarize our approach to CRC screening.

The cost of colorectal cancer according to the TNM stage

INTRODUCTION

The aim of this study was to measure the cost of treatment of colorectal cancer in the Basque public health system according to the clinical stage.

METHODS

We retrospectively collected demographic data, clinical data and resource use of a sample of 529 patients. For stagesi toiii the initial and follow-up costs were measured. The calculation of cost for stageiv combined generalized linear models to relate the cost to the duration of follow-up based on parametric survival analysis. Unit costs were obtained from the analytical accounting system of the Basque Health Service.

RESULTS

The sample included 110 patients with stagei, 171 with stageii, 158 with stageiii and 90 with stageiv colorectal cancer. The initial total cost per patient was 8,644€ for stagei, 12,675€ for stageii and 13,034€ for stageiii. The main component was hospitalization cost. Calculated by extrapolation for stageiv mean survival was 1.27years. Its average annual cost was 22,403€, and 24,509€ to death. The total annual cost for colorectal cancer extrapolated to the whole Spanish health system was 623.9million€.

CONCLUSIONS

The economic burden of colorectal cancer is important and should be taken into account in decision-making. The combination of generalized linear models and survival analysis allows estimation of the cost of metastatic stage.

Cost Effectiveness of Colorectal Cancer Screening Strategies

BACKGROUND

Several screening tests are available to detect colorectal cancer (CRC) and reduce the incidence and mortality of CRC. The purpose of this review was to determine how current CRC screening strategies for CRC compare with no screening and whether agreement exists with regard to the cost effectiveness of different strategies.

METHODS

Databases were searched for cost-effectiveness analyses focused on CRC screening strategies in the United States and published between May 2007 and February 2014. We analyzed the uses of fecal occult blood, fecal immunochemistry, and stool DNA tests, as well as sigmoidoscopy, colonoscopy, and virtual colonoscopy. A paired comparison of each screening strategy with no screening across each of the studies reviewed was conducted. A series of paired comparisons of the results reported in each of the studies is also included.

RESULTS

When compared with no screening, all CRC screening strategies evaluated in this review were cost effective. There was disagreement as to which screening strategy was the most cost effective. However, sigmoidoscopy combined with fecal blood testing always dominated either strategy alone. Studies comparing colonoscopy with fecal blood testing, sigmoidoscopy, or both had mixed results.

CONCLUSIONS

Compared with no screening, all CRC screening strategies are more cost effective. Study results disagree as to which screening strategy should be the preferred method.

Willingness to Pay for CT Colonography: A Survey of Patient Preferences

OBJECTIVE

CT colonography (CTC) has received mixed reviews both in the radiology literature and in clinical practice. CTC is less invasive than optical colonoscopy (OC), is better for identifying polyps, and does not require sedation. However, its cost-effectiveness has been called into question, and there is a residual need for OC if the CTC findings are positive. Some radiologists are hesitant to perform CTC because of the time-intensive nature of its interpretation. Results of willingness-to-pay surveys can be informative about preferences and value placed on intangibles. The purpose of this study was to use such a survey to elicit the preferences of radiologists about CTC versus OC.

SUBJECTS AND METHODS

A vignette was presented in which the insurer covered OC at no charge but required out-of-pocket payment for CTC. The strengths and weaknesses of OC and CTC were listed. The respondents were asked how much they would be willing to pay for CTC; for CTC with perfect sensitivity, specificity, and accuracy; and for CTC that required no bowel preparation.

RESULTS

Twenty-eight of 42 radiologists preferred OC to CTC. One radiologist was indifferent. Four radiologists would reverse their preference and choose CTC if it had 100% sensitivity. Sixteen radiologists said they would prefer CTC if it had 100% specificity. If CTC eliminated the need for bowel preparation, 57% would prefer it to OC. Thirty-one (74%) radiologists preferred perfect sensitivity to perfect specificity.

CONCLUSION

Despite the less invasive nature of CTC, most radiologists who responded to the survey preferred OC for colorectal cancer screening, mostly because of the definitive nature of OC due to the capability of immediate biopsy of suspicious lesions and the lack of requirement for a second round of bowel preparation.

Colorectal cancer screening: a global overview of existing programmes

Colorectal cancer (CRC) ranks third among the most commonly diagnosed cancers worldwide, with wide geographical variation in incidence and mortality across the world. Despite proof that screening can decrease CRC incidence and mortality, CRC screening is only offered to a small proportion of the target population worldwide. Throughout the world there are widespread differences in CRC screening implementation status and strategy. Differences can be attributed to geographical variation in CRC incidence, economic resources, healthcare structure and infrastructure to support screening such as the ability to identify the target population at risk and cancer registry availability. This review highlights issues to consider when implementing a CRC screening programme and gives a worldwide overview of CRC burden and the current status of screening programmes, with focus on international differences.

Computed tomographic colonography compared with colonoscopy or barium enema for diagnosis of colorectal cancer in older symptomatic patients: two multicentre randomised trials with economic evaluation (the SIGGAR trials)

BACKGROUND

Computed tomographic colonography (CTC) is a relatively new diagnostic test that may be superior to existing alternatives to investigate the large bowel.

OBJECTIVES

To compare the diagnostic efficacy, acceptability, safety and cost-effectiveness of CTC with barium enema (BE) or colonoscopy.

DESIGN

Parallel randomised trials: BE compared with CTC and colonoscopy compared with CTC (randomisation 2 : 1, respectively).

SETTING

A total of 21 NHS hospitals.

PARTICIPANTS

Patients aged ≥ 55 years with symptoms suggestive of colorectal cancer (CRC).

INTERVENTIONS

CTC, BE and colonoscopy.

MAIN OUTCOME MEASURES

For the trial of CTC compared with BE, the primary outcome was the detection rate of CRC and large polyps (≥ 10 mm), with the proportion of patients referred for additional colonic investigation as a secondary outcome. For the trial of CTC compared with colonoscopy, the primary outcome was the proportion of patients referred for additional colonic investigation, with the detection rate of CRC and large polyps as a secondary outcome. Secondary outcomes for both trials were miss rates for cancer (via registry data), all-cause mortality, serious adverse events, patient acceptability, extracolonic pathology and cost-effectiveness.

RESULTS

A total of 8484 patients were registered and 5384 were randomised and analysed (BE trial: 2527 BE, 1277 CTC; colonoscopy trial: 1047 colonoscopy, 533 CTC). Detection rates in the BE trial were 7.3% (93/1277) for CTC, compared with 5.6% (141/2527) for BE (p = 0.0390). The difference was due to better detection of large polyps by CTC (3.6% vs. 2.2%; p = 0.0098), with no significant difference for cancer (3.7% vs. 3.4%; p = 0.66). Significantly more patients having CTC underwent additional investigation (23.5% vs. 18.3%; p = 0.0003). At the 3-year follow-up, the miss rate for CRC was 6.7% for CTC (three missed cancers) and 14.1% for BE (12 missed cancers). Significantly more patients randomised to CTC than to colonoscopy underwent additional investigation (30% vs. 8.2%; p < 0.0001). There was no significant difference in detection rates for cancer or large polyps (10.7% for CTC vs. 11.4% for colonoscopy; p = 0.69), with no difference when cancers (p = 0.94) and large polyps (p = 0.53) were analysed separately. At the 3-year follow-up, the miss rate for cancer was nil for colonoscopy and 3.4% for CTC (one missed cancer). Adverse events were uncommon for all procedures. In 1042 of 1748 (59.6%) CTC examinations, at least one extracolonic finding was reported, and this proportion increased with age (p < 0.0001). A total of 149 patients (8.5%) were subsequently investigated, and extracolonic neoplasia was diagnosed in 79 patients (4.5%) and malignancy in 29 (1.7%). In the short term, CTC was significantly more acceptable to patients than BE or colonoscopy. Total costs for CTC and colonoscopy were finely balanced, but CTC was associated with higher health-care costs than BE. The cost per large polyp or cancer detected was £4235 (95% confidence interval £395 to £9656).

CONCLUSIONS

CTC is superior to BE for detection of cancers and large polyps in symptomatic patients. CTC and colonoscopy detect a similar proportion of large polyps and cancers and their costs are also similar. CTC precipitates significantly more additional investigations than either BE or colonoscopy, and evidence-based referral criteria are needed. Further work is recommended to clarify the extent to which patients initially referred for colonoscopy or BE undergo subsequent abdominopelvic imaging, for example by computed tomography, which will have a significant impact on health economic estimates.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN95152621.

CT colonography: accuracy, acceptance, safety and position in organised population screening

Colorectal cancer (CRC) is the second most common cancer and second most common cause of cancer-related deaths in Europe. The introduction of CRC screening programmes using stool tests and flexible sigmoidoscopy, have been shown to reduce CRC-related mortality substantially. In several European countries, population-based CRC screening programmes are ongoing or being rolled out. Stool tests like faecal occult blood testing are non-invasive and simple to perform, but are primarily designed to detect early invasive cancer. More invasive tests like colonoscopy and CT colonography (CTC) aim at accurately detecting both CRC and cancer precursors, thus providing for cancer prevention. This review focuses on the accuracy, acceptance and safety of CTC as a CRC screening technique and on the current position of CTC in organised population screening. Based on the detection characteristics and acceptability of CTC screening, it might be a viable screening test. The potential disadvantage of radiation exposure is probably overemphasised, especially with newer technology. At this time-point, it is not entirely clear whether the detection of extracolonic findings at CTC is of net benefit and is cost effective, but with responsible handling, this may be the case. Future efforts will seek to further improve the technique, refine appropriate diagnostic algorithms and study cost-effectiveness.

Review of economic evidence in the prevention and early detection of colorectal cancer

This paper aims to systematically review the cost-effectiveness evidence, and to provide a critical appraisal of the methods used in the model-based economic evaluation of CRC screening and subsequent surveillance. A search strategy was developed to capture relevant evidence published 1999-November 2012. Databases searched were MEDLINE, EMBASE, National Health Service Economic Evaluation (NHS EED), EconLit, and HTA. Full economic evaluations that considered costs and health outcomes of relevant intervention were included. Sixty-eight studies which used either cohort simulation or individual-level simulation were included. Follow-up strategies were mostly embedded in the screening model. Approximately 195 comparisons were made across different modalities; however, strategies modelled were often simplified due to insufficient evidence and comparators chosen insufficiently reflected current practice/recommendations. Studies used up-to-date evidence on the diagnostic test performance combined with outdated information on CRC treatments. Quality of life relating to follow-up surveillance is rare. Quality of life relating to CRC disease states was largely taken from a single study. Some studies omitted to say how identified adenomas or CRC were managed. Besides deterministic sensitivity analysis, probabilistic sensitivity analysis (PSA) was undertaken in some studies, but the distributions used for PSA were rarely reported or justified. The cost-effectiveness of follow-up strategies among people with confirmed adenomas are warranted in aiding evidence-informed decision making in response to the rapidly evolving technologies and rising expectations.

Colorectal cancer screening--optimizing current strategies and new directions

The first evidence that screening for colorectal cancer (CRC) could effectively reduce mortality dates back 20 years. However, actual population screening has, in many countries, halted at the level of individual testing and discussions on differences between screening tests. With a wealth of new evidence from various community-based studies looking at test uptake, screening-programme organization and the importance of quality assurance, population screening for CRC is now moving into a new realm, promising better results in terms of reducing CRC-specific morbidity and mortality. Such a shift in the paradigm requires a change from opportunistic, individual testing towards organized population screening with comprehensive monitoring and full-programme quality assurance. To achieve this, a combination of factors--including test characteristics, uptake, screenee autonomy, costs and capacity--must be considered. Thus, evidence from randomized trials comparing different tests must be supplemented by studies of acceptance and uptake to obtain the full picture of the effectiveness (in terms of morbidity, mortality and cost) the different strategies have. In this Review, we discuss a range of screening modalities and describe the factors to be considered to achieve a truly effective population CRC screening programme.

Evolving role of computed tomographic colonography in colon cancer screening and diagnosis

Computed tomographic colonography (CTC) is a relatively new imaging modality for the examination of patients for colorectal polyps and cancer. It has been validated in its accuracy for the detection of colon cancer and larger polyps (more than likely premalignant). CTC, however, is not widely accepted as a primary screening modality in the United States at present by many third-party payers, including Medicare, and its exact role in screening is evolving. Moreover, there has been opposition to incorporating CTC as an accepted screening instrument, especially by gastroenterologists. Heretofore, optical colonoscopy has been the mainstay in this screening. We discuss these issues and the continuing controversies concerning CTC.

Unit costs in population-based colorectal cancer screening using CT colonography performed in university hospitals in The Netherlands

OBJECTIVES

Computed tomography (CT) colonography cost assumptions so far ranged from <euro>346 to <euro>594 per procedure, based on clinical CT reimbursement rates. The aim of our study was to estimate the costs in a screening situation.

METHODS

Data were collected within an invitational population-based CRC screening trial (n = 2,920, age 50-75 years) with a dedicated CT-screening setting. Unit costs were calculated per action, per invitee and per participant (depending on adherence) and per individual with detected advanced neoplasia. Sensitivity analyses were performed, and alternative scenarios were considered.

RESULTS

Of the invitees, 47.2 % were reminded, 38.8 % scheduled for an intake, 37.2 % scheduled for CT colonography, 33.6 % underwent CT colonography and 1.1 % needed a re-examination. Lesions ≥ 10 mm were detected in 2.9 % of the invitees. Invitation costs were Euro 5.57. Costs per CT colonography (intake to results) were Euro 144.00. Extra costs of communication of positive results were Euro 9.00. Average costs of invitational-based CT colonography screening were Euro 56.97 per invitee, Euro 169.40 per participant and Euro 2,772.51 per individual with detected advanced neoplasia.

CONCLUSIONS

Dutch costs of CT-screening were substantially lower than the cost assumptions that were used in published cost-effectiveness analyses on CT colonography screening. This finding indicates that previous cost-effectiveness analyses should be updated, at least for the Dutch situation.

Inclusion of compliance and persistence in economic models: past, present and future

Economic models are developed to provide decision makers with information related to the real-world effectiveness of therapeutics, screening and diagnostic regimens. Although compliance with these regimens often has a significant impact on real-world clinical outcomes and costs, compliance and persistence have historically been addressed in a relatively superficial fashion in economic models. In this review, we present a discussion of the current state of economic modelling as it relates to the consideration of compliance and persistence. We discuss the challenges associated with the inclusion of compliance and persistence in economic models and provide an in-depth review of recent modelling literature that considers compliance or persistence, including a brief summary of previous reviews on this topic and a survey of published models from 2005 to 2012. We review the recent literature in detail, providing a therapeutic-area-specific discussion of the approaches and conclusions drawn from the inclusion of compliance or persistence in economic models. In virtually all publications, variation of model parameters related to compliance and persistence was shown to have a significant impact on predictions of economic outcomes. Growing recognition of the importance of compliance and persistence in the context of economic evaluations has led to an increasing number of economic models that consider these factors, as well as the use of more sophisticated modelling techniques such as individual simulations that provide an avenue for more rigorous consideration of compliance and persistence than is possible with more traditional methods. However, we note areas of continuing concern cited by previous reviews, including inconsistent definitions, documentation and tenuous assumptions required to estimate the effect of compliance and persistence. Finally, we discuss potential means to surmount these challenges via more focused efforts to collect compliance and persistence data.

Does CT colonography have a role for population-based colorectal cancer screening?

Colorectal cancer (CRC) is the second most common cancer and second most common cause of cancer-related deaths in Europe. CRC screening has been proven to reduce disease-specific mortality and several European countries employ national screening programmes. These almost exclusively rely on stool tests, with endoscopy used as an adjunct in some countries. Computed tomographic colonography (CTC) is a potential screening test, with an estimated sensitivity of 88 % for advanced neoplasia ≥10 mm. Recent randomised studies have shown that CTC and colonoscopy have similar yields of advanced neoplasia per screened invitee, indicating that CTC is potentially viable as a primary screening test. However, the evidence is not fully elaborated. It is unclear whether CTC screening is cost-effective and the impact of extracolonic findings, both medical and economic, remains unknown. Furthermore, the effect of CTC screening on CRC-related mortality is unknown, as it is also unknown for colonoscopy. It is plausible that both techniques could lead to decreased mortality, as for sigmoidoscopy and gFOBT. Although radiation exposure is a drawback, this disadvantage may be over-emphasised. In conclusion, the detection characteristics and acceptability of CTC suggest it is a viable screening investigation. Implementation will depend on detection of extracolonic disease and health-economic impact. Key Points • Meta-analysis of CT colonographic screening showed high sensitivity for advanced neoplasia ≥10mm. • CTC, colonoscopy and sigmoidoscopy screening all have similar yields for advanced neoplasia. • Good quality information regarding the cost-effectiveness of CTC screening is lacking. • There is little good quality data regarding the impact of extracolonic findings. • CTC triage is not clinically effective in first round gFOBT/FIT positives.