Colorectal neoplasia screening with virtual colonoscopy: when, at what cost, and with what national impact?

Comparative Effectiveness and Cost-Effectiveness of Colorectal Cancer Screening With Blood-Based Biomarkers (Liquid Biopsy) vs Fecal Tests or Colonoscopy

BACKGROUND & AIMS

Colorectal cancer (CRC) screening is highly effective but underused. Blood-based biomarkers (liquid biopsy) could improve screening participation.

METHODS

Using our established Markov model, screening every 3 years with a blood-based test that meets minimum Centers for Medicare & Medicaid Services' thresholds (CMSmin) (CRC sensitivity 74%, specificity 90%) was compared with established alternatives. Test attributes were varied in sensitivity analyses.

RESULTS

CMSmin reduced CRC incidence by 40% and CRC mortality by 52% vs no screening. These reductions were less profound than the 68%-79% and 73%-81%, respectively, achieved with multi-target stool DNA (Cologuard; Exact Sciences) every 3 years, annual fecal immunochemical testing (FIT), or colonoscopy every 10 years. Assuming the same cost as multi-target stool DNA, CMSmin cost $28,500/quality-adjusted life-year gained vs no screening, but FIT, colonoscopy, and multi-target stool DNA were less costly and more effective. CMSmin would match FIT's clinical outcomes if it achieved 1.4- to 1.8-fold FIT's participation rate. Advanced precancerous lesion (APL) sensitivity was a key determinant of a test's effectiveness. A paradigm-changing blood-based test (sensitivity >90% for CRC and 80% for APL; 90% specificity; cost ≤$120-$140) would be cost-effective vs FIT at comparable participation.

CONCLUSIONS

CMSmin could contribute to CRC control by achieving screening in those who will not use established methods. Substituting blood-based testing for established effective CRC screening methods will require higher CRC and APL sensitivities that deliver programmatic benefits matching those of FIT. High APL sensitivity, which can result in CRC prevention, should be a top priority for screening test developers. APL detection should not be penalized by a definition of test specificity that focuses on CRC only.

Contrasting Effectiveness and Cost-Effectiveness of Colorectal Cancer Screening Under Commercial Insurance vs. Medicare

OBJECTIVES

Most cost-effectiveness analyses of colorectal cancer (CRC) screening assume Medicare payment rates and a lifetime horizon. Our aims were to examine the implications of differential payment levels and time horizons for commercial insurers vs. Medicare on the cost-effectiveness of CRC screening.

METHODS

We used our validated Markov cohort simulation of CRC screening in the average risk US population to examine CRC screening at ages 50-64 under commercial insurance, and at ages 65-80 under Medicare, using a health-care sector perspective. Model outcomes included discounted quality-adjusted life-years (QALYs) and costs per person, and incremental cost/QALY gained.

RESULTS

Lifetime costs/person were 20-44% higher when assuming commercial payment rates rather than Medicare rates for people under 65. Most of the substantial clinical benefit of screening at ages 50-64 was realized at ages ≥65. For commercial payers with a time horizon of ages 50-64, fecal occult blood testing (FOBT) and fecal immunochemical testing (FIT) were cost-effective (<$61,000/QALY gained), but colonoscopy was costly (>$185,000/QALY gained). Medicare experienced substantial clinical benefits and cost-savings from screening done at ages <65, even if screening was not continued. Among those previously screened, continuing FOBT and FIT under Medicare was cost-saving and continuing colonoscopy was highly cost-effective (<$30,000/QALY gained), and initiating any screening in those previously unscreened was highly effective and cost-saving.

CONCLUSIONS

Modeling suggests that CRC screening is highly cost-effective over a lifetime even when considering higher payment rates by commercial payers vs. Medicare. Screening may appear relatively costly for commercial payers if only a time horizon of ages 50-64 is considered, but it is predicted to yield substantial clinical and economic benefits that accrue primarily at ages ≥65 under Medicare.

Cost-effectiveness of the faecal immunochemical test at a range of positivity thresholds compared with the guaiac faecal occult blood test in the NHS Bowel Cancer Screening Programme in England

OBJECTIVES

Through the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP), men and women in England aged between 60 and 74 years are invited for colorectal cancer (CRC) screening every 2 years using the guaiac faecal occult blood test (gFOBT). The aim of this analysis was to estimate the cost-utility of the faecal immunochemical test for haemoglobin (FIT) compared with gFOBT for a cohort beginning screening aged 60 years at a range of FIT positivity thresholds.

DESIGN

We constructed a cohort-based Markov state transition model of CRC disease progression and screening. Screening uptake, detection, adverse event, mortality and cost data were taken from BCSP data and national sources, including a recent large pilot study of FIT screening in the BCSP.

RESULTS

Our results suggest that FIT is cost-effective compared with gFOBT at all thresholds, resulting in cost savings and quality-adjusted life years (QALYs) gained over a lifetime time horizon. FIT was cost-saving (p<0.001) and resulted in QALY gains of 0.014 (95% CI 0.012 to 0.017) at the base case threshold of 180 µg Hb/g faeces. Greater health gains and cost savings were achieved as the FIT threshold was decreased due to savings in cancer management costs. However, at lower thresholds, FIT was also associated with more colonoscopies (increasing from 32 additional colonoscopies per 1000 people invited for screening for FIT 180 µg Hb/g faeces to 421 additional colonoscopies per 1000 people invited for screening for FIT 20 µg Hb/g faeces over a 40-year time horizon). Parameter uncertainty had limited impact on the conclusions.

CONCLUSIONS

This is the first published economic analysis of FIT screening in England using data directly comparing FIT with gFOBT in the NHS BSCP. These results for a cohort starting screening aged 60 years suggest that FIT is highly cost-effective at all thresholds considered. Further modelling is needed to estimate economic outcomes for screening across all age cohorts simultaneously.

Comparative Effectiveness and Cost Effectiveness of a Multitarget Stool DNA Test to Screen for Colorectal Neoplasia

BACKGROUND & AIMS

We developed a model to determine whether a multitarget stool DNA (MT-sDNA) test that detects colorectal cancer (CRC) and polyps with higher sensitivity and lower specificity, but at a higher cost, than the fecal immunochemical test (FIT) can be used in screening.

METHODS

We used a Markov model of average-risk CRC screening to compare the effectiveness and cost effectiveness of screening with the MT-sDNA test vs FIT or colonoscopy. We accounted for the complex longitudinal participation patterns observed in organized programs vs opportunistic screening, as well as organized programs' patient support costs and differential payment rates by commercial insurers vs Medicare.

RESULTS

With optimal adherence, yearly FIT and colonoscopy every 10 years were dominant (more effective and less costly) than MT-sDNA every 3 years. Compared with successful organized FIT programs (50% consistent and 27% intermittent participation; patient support costs, $153/cycle), the patient support program for the MT-sDNA test would need 68% of subjects to participate consistently and 32% to participate intermittently every 3 years, or the MT-sDNA test would need to cost 60% less than in the base case ($260 commercial payment and $197 Medicare payment), for the MT-sDNA test to be preferred over FIT at a threshold of $100,000 per quality-adjusted life-year (QALY) gained. Compared with opportunistic yearly FIT screening (15% consistent and 30% intermittent participation), performing the MT-sDNA test every 3 years would cost less than $100,000 per QALY gained if the MT-sDNA test achieved a participation rate more than 1.7-fold that of FIT. The results were robust in sensitivity analyses. Assuming equal participation across strategies and a threshold of $100,000 per QALY gained, FIT was preferred in 99.3% of iterations in Monte Carlo simulation.

CONCLUSIONS

In a Markov model, we found FIT and colonoscopy to be more effective and less costly than the MT-sDNA test when participation rates were equal for all strategies. For the MT-sDNA test to be cost effective, the patient support program included in its cost would need to achieve substantially higher participation rates than those of FIT, whether in organized programs or under the opportunistic screening setting that is more common in the United States than in the rest of the world.

Cost Differences After Initial CT Colonography Versus Optical Colonoscopy in the Elderly

RATIONALE AND OBJECTIVES

To compare differences in Medicare costs 1 year after initial computed tomographic colonography (CTC) or initial optical colonoscopy (OC).

MATERIALS AND METHODS

We performed a retrospective cohort study of asymptomatic Medicare outpatients aged ≥ 66 years who received initial CTC (n = 531) or OC (n = 17,593) between January 2007 and December 2008; initial OC patients were matched on county of residence and year of screening. Outcomes included differences in total inpatient and outpatient Medicare costs 1 year after initial CTC or OC and differences in outpatient testing of potential findings in the colon, abdomen, pelvis, and lungs.

RESULTS

Higher adjusted costs per patient were revealed in the year after initial CTC compared to initial OC for outpatient testing related to potential colonic ($50; 95% confidence interval [CI], $12-$88; P = .010) and extracolonic findings ($64; 95% CI, $23-$106; P = .002). However, there were no differences in adjusted total costs per patient in the year after either modality ($2065; 95% CI, $1672-$5803; P = .28). Similarly, adjusted costs did not differ between cohorts for inpatient ($267; 95% CI, $1017-$1550; P = .68) or outpatient care ($2828; 95% CI, $311-$5966; P = .08).

CONCLUSIONS

Despite higher adjusted costs of outpatient testing potentially related to colonic and extracolonic findings among asymptomatic elderly patients 1 year after initial CTC compared to OC, we found no differences in adjusted total, inpatient, or outpatient costs between cohorts. Although Medicare does not cover screening CTC, our results suggest that these modalities generate comparable downstream costs to payers.

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.

Cost-effectiveness of CT colonography

Simulation modeling is extensively applied to CT colonography (CTC) to define its long-term efficacy and cost-effectiveness for colorectal cancer (CRC) screening. CTC is effective in reducing CRC incidence and mortality (40%-77% and 58%-84%, respectively). Several factors may explain this variability. CTC is cost-effective compared with no screening, indicating that it represents an attractive test noncompliance with the available options. CTC needs to achieve a higher attendance rate or cost less than colonoscopy to be cost-effective relative to colonoscopy. Fortunately, both conditions appear to be achievable if CTC becomes a widely utilized and reimbursed screening tool.

Comparative effectiveness and cost-effectiveness of screening colonoscopy vs. sigmoidoscopy and alternative strategies

OBJECTIVES

Fecal occult blood testing (FOBT) and sigmoidoscopy are proven to decrease colorectal cancer (CRC) incidence and mortality. Sigmoidoscopy's benefit is limited to the distal colon. Observational data are conflicting regarding the degree to which colonoscopy affords protection against proximal CRC. Our aim was to explore the comparative effectiveness and cost-effectiveness of colonoscopy vs. sigmoidoscopy and alternative CRC screening strategies in light of the latest published data.

METHODS

We performed a contemporary cost-utility analysis using a Markov model validated against data from randomized controlled trials of FOBT and sigmoidoscopy. Persons at average CRC risk within the general US population were modeled. Screening strategies included those recommended by the United States (US) Preventive Services Task Force, including colonoscopy every 10 years (COLO), flexible sigmoidoscopy every 5 years (FS), annual fecal occult blood testing, annual fecal immunochemical testing (FIT), and the combination FS/FIT. The main outcome measures were quality-adjusted life-years (QALYs) and costs.

RESULTS

In the base case, FIT dominated other strategies. The advantage of FIT over FS and COLO was contingent on rates of uptake and adherence that are well above current US rates. Compared with FIT, FS and COLO both cost <$50,000/QALY gained when FIT per-cycle adherence was <50%. COLO cost $56,800/QALY gained vs. FS in the base case. COLO cost <$100,000/QALY gained vs. FS when COLO yielded a relative risk of proximal CRC of <0.5 vs. no screening. In probabilistic analyses, COLO was cost-effective vs. FS at a willingness-to-pay threshold of $100,000/QALY gained in 84% of iterations.

CONCLUSIONS

Screening colonoscopy may be cost-effective compared with FIT and sigmoidoscopy, depending on the relative rates of screening uptake and adherence and the protective benefit of colonoscopy in the proximal colon. Colonoscopy's cost-effectiveness compared with sigmoidoscopy is contingent on the ability to deliver ~50% protection against CRC in the proximal colon.

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.

Cost-effectiveness of computed tomography colonography in colorectal cancer screening: a systematic review

OBJECTIVES

The European Code Against Cancer recommends individuals aged ≥ 50 should participate in colorectal cancer screening. CT-colonography (CTC) is one of several screening tests available. We systematically reviewed evidence on, and identified key factors influencing, cost-effectiveness of CTC screening.

METHODS

PubMed, Medline, and the Cochrane library were searched for cost-effectiveness or cost-utility analyses of CTC-based screening, published in English, January 1999 to July 2010. Data was abstracted on setting, model type and horizon, screening scenario(s), comparator(s), participants, uptake, CTC performance and cost, effectiveness, ICERs, and whether extra-colonic findings and medical complications were considered.

RESULTS

Sixteen studies were identified from the United States (n = 11), Canada (n = 2), and France, Italy, and the United Kingdom (1 each). Markov state-transition (n = 14) or microsimulation (n = 2) models were used. Eleven considered direct medical costs only; five included indirect costs. Fourteen compared CTC with no screening; fourteen compared CTC with colonoscopy-based screening; fewer compared CTC with sigmoidoscopy (8) or fecal tests (4). Outcomes assessed were life-years gained/saved (13), QALYs (2), or both (1). Three considered extra-colonic findings; seven considered complications. CTC appeared cost-effective versus no screening and, in general, flexible sigmoidoscopy and fecal occult blood testing. Results were mixed comparing CTC to colonoscopy. Parameters most influencing cost-effectiveness included: CTC costs, screening uptake, threshold for polyp referral, and extra-colonic findings.

CONCLUSION

Evidence on cost-effectiveness of CTC screening is heterogeneous, due largely to between-study differences in comparators and parameter values. Future studies should: compare CTC with currently favored tests, especially fecal immunochemical tests; consider extra-colonic findings; and conduct comprehensive sensitivity analyses.

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.

Physician knowledge and appropriate utilization of computed tomographic colonography in colorectal cancer screening

GOALS

To assess physician understanding of computed tomographic colonography (CTC) in colorectal cancer (CRC) screening guidelines in a pilot study.

BACKGROUND

CTC is a sensitive and specific method of detecting colorectal polyps and cancer. However, several factors have limited its clinical availability, and CRC screening guidelines have issued conflicting recommendations.

STUDY

A web-based survey was administered to physicians at two institutions with and without routine CTC availability.

RESULTS

398 of 1655 (24%) participants completed the survey, 59% was from the institution with routine CTC availability, 52% self-identified as trainees, and 15% as gastroenterologists. 78% had no personal experience with CTC. Only 12% was aware of any current CRC screening guidelines that included CTC. In a multiple regression model, gastroenterologists had greater odds of being aware of guidelines (OR 3.49, CI 1.67-7.26), as did physicians with prior CTC experience (OR 4.81, CI 2.39-9.68), controlling for institution, level of training, sex, and practice type. Based on guidelines that recommend CTC, when given a clinical scenario, 96% of physicians was unable to select the appropriate follow-up after a CTC, which was unaffected by institution.

CONCLUSIONS

Most physicians have limited experience with CTC and are unaware of recent recommendations concerning CTC in CRC screening.

Computer disease simulation models: integrating evidence for health policy

Computer disease simulation models are increasingly being used to evaluate and inform health care decisions across medical disciplines. The aim of researchers who develop these models is to integrate and synthesize short-term outcomes and results from multiple sources to predict the long-term clinical outcomes and costs of different health care strategies. Policy makers, in turn, can use the predictions generated by disease models together with other evidence to make decisions related to health care practices and resource utilization. Models are particularly useful when the existing evidence does not yield obvious answers or does not provide answers to the questions of greatest interest, such as questions about the relative cost-effectiveness of different practices. This review focuses on models used to inform decisions about imaging technology, discussing the role of disease models for health policy development and providing a foundation for understanding the basic principles of disease modeling. This manuscript draws from the collective computed tomographic colonography modeling experience, reviewing 10 published investigations of the clinical effectiveness and cost-effectiveness of computed tomographic colonography relative to colonoscopy. The discussion focuses on implications of different modeling assumptions and difficulties that may be encountered when evaluating the quality of models. This underscores the importance of forging stronger collaborations between researchers who develop disease models and radiologists, to ensure that policy-level models accurately represent the experience of everyday clinical practices.

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

PURPOSE

To estimate the cost-effectiveness of computed tomographic (CT) colonography for colorectal cancer (CRC) screening in average-risk asymptomatic subjects in the United States aged 50 years.

MATERIALS AND METHODS

Enrollees in the American College of Radiology Imaging Network National CT Colonography Trial provided informed consent, and approval was obtained from the institutional review board at each site. CT colonography performance estimates from the trial were incorporated into three Cancer Intervention and Surveillance Modeling Network CRC microsimulations. Simulated survival and lifetime costs for screening 50-year-old subjects in the United States with CT colonography every 5 or 10 years were compared with those for guideline-concordant screening with colonoscopy, flexible sigmoidoscopy plus either sensitive unrehydrated fecal occult blood testing (FOBT) or fecal immunochemical testing (FIT), and no screening. Perfect and reduced screening adherence scenarios were considered. Incremental cost-effectiveness and net health benefits were estimated from the U.S. health care sector perspective, assuming a 3% discount rate.

RESULTS

CT colonography at 5- and 10-year screening intervals was more costly and less effective than FOBT plus flexible sigmoidoscopy in all three models in both 100% and 50% adherence scenarios. Colonoscopy also was more costly and less effective than FOBT plus flexible sigmoidoscopy, except in the CRC-SPIN model assuming 100% adherence (incremental cost-effectiveness ratio: $26,300 per life-year gained). CT colonography at 5- and 10-year screening intervals and colonoscopy were net beneficial compared with no screening in all model scenarios. The 5-year screening interval was net beneficial over the 10-year interval except in the MISCAN model when assuming 100% adherence and willingness to pay $50,000 per life-year gained.

CONCLUSION

All three models predict CT colonography to be more costly and less effective than non-CT colonographic screening but net beneficial compared with no screening given model assumptions.

Cost-effectiveness of colorectal cancer screening

Colorectal cancer is an important public health problem. Several screening methods have been shown to be effective in reducing colorectal cancer mortality. The objective of this review was to assess the cost-effectiveness of the different colorectal cancer screening methods and to determine the preferred method from a cost-effectiveness point of view. Five databases (MEDLINE, EMBASE, the Cost-Effectiveness Analysis Registry, the British National Health Service Economic Evaluation Database, and the lists of technology assessments of the Centers for Medicare and Medicaid Services) were searched for cost-effectiveness analyses published in English between January 1993 and December 2009. Fifty-five publications relating to 32 unique cost-effectiveness models were identified. All studies found that colorectal cancer screening was cost-effective or even cost-saving compared with no screening. However, the studies disagreed as to which screening method was most effective or had the best incremental cost-effectiveness ratio for a given willingness to pay per life-year gained. There was agreement among studies that the newly developed screening tests of stool DNA testing, computed tomographic colonography, and capsule endoscopy were not yet cost-effective compared with the established screening options.

Nonmedical costs of colorectal cancer screening using CT colonography

PURPOSE

Nonmedical costs are important because they may influence screening uptake and the results of cost-effectiveness analyses of colorectal cancer (CRC) screening. Although the nonmedical costs of CRC screening are known for fecal occult blood testing, flexible sigmoidoscopy, and colonoscopy, they are unknown for CT colonography (CTC). The purpose of this study was to determine the nonmedical costs of CTC.

METHODS

Four hundred eighty-one consecutive individuals presenting for CRC screening using CTC were approached at a radiology clinic in Calgary, Alberta, Canada, to participate in the study. Of these, 197 agreed to have a questionnaire mailed to them. Subjects completed the questionnaire, including items on time off work, both for the subject and any accompanying caregiver; travel details; and direct out-of-pocket expenses. Time costs were valued at government of Canada wage rates. Travel costs included estimated costs for travel by car and actual parking costs and taxi and public transportation fares. Car user's costs were calculated using a Canadian Automobile Association estimate of motoring costs per kilometer. Costs are reported in 2010 Canadian dollars.

RESULTS

One hundred thirty-two subjects returned the questionnaire (mean age, 57 years; 65% men; 67% employed). Ten subjects traveled >200 km for their CTC. The nonmedical costs (subject with or without caregiver) for the 122 subjects who resided within 200 km of the clinic averaged $101.

CONCLUSIONS

The nonmedical costs of CRC screening using CTC are significant but lower than those of colonoscopy. Patients should be aware of these differential costs, and they should be incorporated into economic analyses of CRC screening.

Computed tomographic colonography

This article provides basic information about computed tomographic colonography (CTC) and reviews the preparation, methods, and tools required for the procedure. The clinical uses for CTC (screening/diagnosis of colon cancer and colonic obstruction) are outlined, and its accuracy and validity are compared with other diagnostic methods. A summary of the benefits and risks of the test are presented and the current practicalities for implementation are addressed.

Cost-effectiveness of colorectal cancer screening with computed tomography colonography or fecal blood tests

OBJECTIVE

To assess the cost-effectiveness of colorectal cancer screening using computed tomography colonography (CTC) and immunological fecal occult blood test (iFOBT).

METHODS

CTC and iFOBT strategies were compared with Nn screening or guaiac FOBT (gFOBT) using Markov modeling. CTC was proposed at 50, 60, and 70 years, whereas gFOBT and iFOBT were performed every 2 years beginning at 50 years until 74 years of age with a 30-year time horizon. We calculated incremental cost-effectiveness ratios and efficiency ratios (ERs). Then, we performed univariate and probabilistic sensitivity analyses.

RESULTS

With gFOBT as reference, colorectal cancer prevention rate was 18% for CTC and 11% for iFOBT. The incremental cost-effectiveness ratio of CTC and iFOBT were respectively 3204 and 5458 euro per life years gained (LYG), the ER for CTC was 0.22 and the ER for iFOBT was 2.08 colonoscopies per LYG. Cost-effectiveness results were sensitive to CTC cost. In the probabilistic sensitivity analysis, compared with CTC, iFOBT strategy was cost-effective for 84.6% of simulations when we assumed a willingness to pay (WTP) of 20,000 euro/LYG.

CONCLUSION

CTC requires substantially less colonoscopies than iFOBT and is cost-effective for low values of WTP. However, iFOBT is the preferred screening strategy for a WTP greater than 6207 euro/LYG.

Cost-effectiveness of colorectal cancer screening in high-risk Spanish patients: use of a validated model to inform public policy

BACKGROUND

The European Community has made a commitment to colorectal cancer (CRC) screening, but regional considerations may affect the design of national screening programs. We developed a decision analytic model tailored to a pilot screening program for high-risk persons in Spain with the aim of informing public policy decisions.

MATERIALS AND METHODS

We constructed a decision analytic Markov model based on our validated model of CRC screening that reflected CRC epidemiology and costs in persons with first-degree relatives with CRC in Aragón, Spain, and superimposed colonoscopy every 5 or 10 years from ages 40 to 80 years. The pilot program's preliminary clinical results and our modeling results were presented to regional health authorities.

RESULTS

In the model, without screening, 88 CRC cases occurred per 1,000 persons from age 40 to 85 years. In the base case, screening reduced this by 72% to 77% and gained 0.12 discounted life years per person. Screening every 10 years was cost saving, and screening every 5 years versus every 10 years cost 7,250 euros per life year gained. Based on these savings, 36 to 39 euros per person per year could go toward operating costs while maintaining a neutral budget. If screening costs doubled, screening remained highly cost-effective but no longer cost saving. These results contributed to the health authorities' decision to expand the pilot program to the entire region in 2009.

CONCLUSIONS

Colonoscopic screening of first-degree relatives of persons with CRC may be cost saving in public systems like that of Spain. Decision analytic modeling tailored to regional considerations can inform public policy decisions.

IMPACT

Tailored decision analytic modeling can inform regional policy decisions on cancer screening.

Colorectal cancer screening: The role of CT colonography

Computed tomography colonography (CTC) in colorectal cancer (CRC) screening has two roles: one present and the other potential. The present role is, without any further discussion, the integration into established screening programs as a replacement for barium enema in the case of incomplete colonoscopy. The potential role is the use of CTC as a first-line screening method together with Fecal Occult Blood Test, sigmoidoscopy and colonoscopy. However, despite the fact that CTC has been officially endorsed for CRC screening of average-risk individuals by different scientific societies including the American Cancer Society, the American College of Radiology, and the US Multisociety Task Force on Colorectal Cancer, other entities, such as the US Preventive Services Task Force, have considered the evidence insufficient to justify its use as a mass screening method. Medicare has also recently denied reimbursement for CTC as a screening test. Nevertheless, multiple advantages exist for using CTC as a CRC screening test: high accuracy, full evaluation of the colon in virtually all patients, non-invasiveness, safety, patient comfort, detection of extracolonic findings and cost-effectiveness. The main potential drawback of a CTC screening is the exposure to ionizing radiation. However, this is not a major issue, since low-dose protocols are now routinely implemented, delivering a dose comparable or slightly superior to the annual radiation exposure of any individual. Indirect evidence exists that such a radiation exposure does not induce additional cancers.

Cost-effectiveness of computed tomographic colonography screening for colorectal cancer in the medicare population

BACKGROUND

The Centers for Medicare and Medicaid Services (CMS) considered whether to reimburse computed tomographic colonography (CTC) for colorectal cancer screening of Medicare enrollees. To help inform its decision, we evaluated the reimbursement rate at which CTC screening could be cost-effective compared with the colorectal cancer screening tests that are currently reimbursed by CMS and are included in most colorectal cancer screening guidelines, namely annual fecal occult blood test (FOBT), flexible sigmoidoscopy every 5 years, flexible sigmoidoscopy every 5 years in conjunction with annual FOBT, and colonoscopy every 10 years.

METHODS

We used three independently developed microsimulation models to assess the health outcomes and costs associated with CTC screening and with currently reimbursed colorectal cancer screening tests among the average-risk Medicare population. We assumed that CTC was performed every 5 years (using test characteristics from either a Department of Defense CTC study or the National CTC Trial) and that individuals with findings of 6 mm or larger were referred to colonoscopy. We computed incremental cost-effectiveness ratios for the currently reimbursed screening tests and calculated the maximum cost per scan (ie, the threshold cost) for the CTC strategy to lie on the efficient frontier. Sensitivity analyses were performed on key parameters and assumptions.

RESULTS

Assuming perfect adherence with all tests, the undiscounted number life-years gained from CTC screening ranged from 143 to 178 per 1000 65-year-olds, which was slightly less than the number of life-years gained from 10-yearly colonoscopy (152-185 per 1000 65-year-olds) and comparable to that from 5-yearly sigmoidoscopy with annual FOBT (149-177 per 1000 65-year-olds). If CTC screening was reimbursed at $488 per scan (slightly less than the reimbursement for a colonoscopy without polypectomy), it would be the most costly strategy. CTC screening could be cost-effective at $108-$205 per scan, depending on the microsimulation model used. Sensitivity analyses showed that if relative adherence to CTC screening was 25% higher than adherence to other tests, it could be cost-effective if reimbursed at $488 per scan.

CONCLUSIONS

CTC could be a cost-effective option for colorectal cancer screening among Medicare enrollees if the reimbursement rate per scan is substantially less than that for colonoscopy or if a large proportion of otherwise unscreened persons were to undergo screening by CTC.

The cost-effectiveness of screening for colorectal cancer

BACKGROUND

Published decision analyses show that screening for colorectal cancer is cost-effective. However, because of the number of tests available, the optimal screening strategy in Canada is unknown. We estimated the incremental cost-effectiveness of 10 strategies for colorectal cancer screening, as well as no screening, incorporating quality of life, noncompliance and data on the costs and benefits of chemotherapy.

METHODS

We used a probabilistic Markov model to estimate the costs and quality-adjusted life expectancy of 50-year-old average-risk Canadians without screening and with screening by each test. We populated the model with data from the published literature. We calculated costs from the perspective of a third-party payer, with inflation to 2007 Canadian dollars.

RESULTS

Of the 10 strategies considered, we focused on three tests currently being used for population screening in some Canadian provinces: low-sensitivity guaiac fecal occult blood test, performed annually; fecal immunochemical test, performed annually; and colonoscopy, performed every 10 years. These strategies reduced the incidence of colorectal cancer by 44%, 65% and 81%, and mortality by 55%, 74% and 83%, respectively, compared with no screening. These strategies generated incremental cost-effectiveness ratios of $9159, $611 and $6133 per quality-adjusted life year, respectively. The findings were robust to probabilistic sensitivity analysis. Colonoscopy every 10 years yielded the greatest net health benefit.

INTERPRETATION

Screening for colorectal cancer is cost-effective over conventional levels of willingness to pay. Annual high-sensitivity fecal occult blood testing, such as a fecal immunochemical test, or colonoscopy every 10 years offer the best value for the money in Canada.

Performance of CT colonography for detecting small, diminutive, and flat polyps

The primary goal of colorectal cancer screening and prevention is the detection and removal of advanced neoplasia. Computerized tomography (CT) colonography is now well established as an effective screening test. Areas of greater uncertainty include the performance characteristics of CT colonography for detecting small (6-9 mm), diminutive (< or =5 mm), and flat (nonpolypoid) lesions. However, the actual clinical relevance of small, diminutive, and flat polyps has also been the source of debate. This article addresses these controversial and often misunderstood issues.

Computed tomographic colonography: Hope or hype?

Computed tomographic colonography (CTC) is a promising emerging technology for imaging of the colon. This concise review discusses the currently available data on CTC technique, test characteristics, acceptance, safety, cost-effectiveness, follow-up strategy, and extracolonic findings. In summary, CTC technique is still evolving, and further research is needed to clarify the role of automated colonic insufflation, smooth-muscle relaxants, intravenous and oral contrast, software rendering, and patient positioning. Currently, full bowel preparation is still required to achieve optimal results. The sensitivity for detecting large polyps (> 1 cm) can be as high as 85%, with specificity of up to 97%. These test characteristics are almost comparable to those of conventional colonoscopy. Patient acceptance of CTC is generally higher than that for colonoscopy, especially in patients who have never undergone either procedure. CTC is generally safe, although uncommon instances of colonic perforation have been documented. In terms of cost-effectiveness, most decision analyses have concluded that CTC would only be cost-effective if it were considerably cheaper than conventional colonoscopy. The proper follow-up strategy for small polyps or incidental extracolonic findings discovered during CTC is still under debate. At present, the exact clinical role of virtual colonoscopy still awaits determination. Even though widespread CTC screening is not available today, in the future there may eventually be a role for this technology. Technological advances in this area will undoubtedly continue, with multi-detector row CT scanners allowing thinner collimation and higher resolution images. Stool-tagging techniques are likely to evolve and may eventually allow for low-preparation CTC. Perceptual and fatigue-related reading errors can potentially be minimized with the help of computer-aided detection software. Further research will define the exact role of this promising technology in our diagnostic armamentarium.

ACR Colon Cancer Committee white paper: status of CT colonography 2009

PURPOSE

To review the current status and rationale of the updated ACR practice guidelines for CT colonography (CTC).

METHODS

Clinical validation trials in both the United States and Europe are reviewed. Key technical aspects of the CTC examination are emphasized, including low-dose protocols, proper insufflation, and bowel preparation. Important issues of implementation are discussed, including training and certification, definition of the target lesion, reporting of colonic and extracolonic findings, quality metrics, reimbursement, and cost-effectiveness.

RESULTS

Successful validation trials in screening cohorts both in the United States with ACRIN and in Germany demonstrated sensitivity > or = 90% for patients with polyps >10 mm. Proper technique is critical, including low-dose techniques in screening cohorts, with an upper limit of the CT dose index by volume of 12.5 mGy per examination. Training new readers includes the requirement of interactive workstation training with 2-D and 3-D image display techniques. The target lesion is defined as a polyp > or = 6 mm, consistent with the American Cancer Society joint guidelines. Five quality metrics have been defined for CTC, with pilot data entered. Although the CMS national noncoverage decision in May 2009 was a disappointment, multiple third-party payers are reimbursing for screening CTC. Cost-effective modeling has shown CTC to be a dominant strategy, including in a Medicare cohort.

CONCLUSION

Supported by third-party payer reimbursement for screening, CTC will continue to further transition into community practice and can provide an important adjunctive examination for colorectal screening.

Cost effectiveness of CT colonography for UK NHS colorectal cancer screening of asymptomatic adults aged 60-69 years

BACKGROUND

Screening of populations at risk for colorectal cancer (CRC) allows the detection and successful treatment of tumours and their precursor polyps. The current UK CRC screening programme is faecal occult blood testing (FOBT), despite evidence from modelling studies to suggest that more cost-effective technologies exist.

OBJECTIVE

To assess the cost effectiveness of CT colonography (CTC) for colorectal cancer screening from the perspective of the UK NHS.

METHODS

A state-transition Markov model was constructed to estimate lifetime costs and health outcomes of a cohort of individuals screened at age 60-69 years using four different CRC screening technologies: FOBT, flexible sigmoidoscopy, optical colonoscopy and CTC.

RESULTS

CTC screening offered every 10 years was cost saving compared with the current UK programme of biennial FOBT screening. This strategy also yielded greater health benefits (QALYs and life-years) than biennial FOBT screening. The model fit observed CRC epidemiology data well and was robust to changes in underlying parameter values. CTC remained cost effective under a range of assumptions in the univariate sensitivity analysis. However, in the probabilistic sensitivity analysis, CTC dominated FOBT in only 5.9% of simulations and was cost effective at a threshold of pound30,000 per QALY gained in 48% of simulations.

CONCLUSIONS

CTC has the potential to provide a cost-effective option for CRC screening in the UK NHS and may be cost saving compared with the current programme of biennial FOBT. Further analysis is required to assess the impact of introducing CTC to the UK CRC screening programme on the NHS budget and capacity.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Computed tomographic colonography: current perspectives and future directions

Computed tomographic (CT) colonography, also known as virtual colonoscopy or CT colography, is capable of detecting colon polyps and cancers. It is emerging rapidly and has gained great momentum over the past several years, to the point where it has been proposed to be a viable primary colon cancer screening option. Despite the current publicity, many issues concerning CT colonography remain. As of 2009, the following topics are of paramount importance: (1) accuracy, including both sensitivity and specificity, (2) bowel preparation, (3) safety, (4) extracolonic findings, (5) patient acceptability, (6) training and standardization, and (7) implementation of CT colonography. Although much about CT colonography has already been learned, more remains to be learned in the future.

Individualizing colonoscopy screening by sex and race

BACKGROUND

There is increasing discussion whether colorectal cancer (CRC) screening guidelines should be individualized by sex and race.

OBJECTIVES

To determine individualized colonoscopic screening guidelines by sex and race for the average-risk population and to compare the cost-effectiveness of this approach with that of uniform guidelines for all.

DESIGN

We used the MISCAN-Colon microsimulation model to estimate life expectancy and lifetime CRC screening and treatment costs in a U.S. cohort of black and white men and women at average risk for CRC. We compared the base-case strategy of no screening and 3 competing colonoscopy strategies: (1) the currently recommended "uniform 10-yearly colonoscopy from age 50 years," (2) a shorter interval "uniform 8-yearly colonoscopy from age 51 years," and (3) "individualized screening according to sex and race."

RESULTS

The base-case strategy of no screening was the least expensive, yet least effective. The uniform 10-yearly colonoscopy strategy was dominated. The uniform 8-yearly colonoscopy and individualized strategies both increased life expectancy by 0.0433 to 0.0435 years per individual, at a cost of $15,565 to $15,837 per life-year gained. In the individualized strategy, blacks began screening 6 years earlier, with a 1-year shorter interval compared with whites. The individualized policies were essentially the same for men and women, because the higher CRC risk in men was offset by their shorter life expectancy. The results were robust for changes in model assumptions.

CONCLUSIONS

The improvements in costs and effects of individualizing CRC screening on a population level were only marginal. Individualized guidelines, however, could contribute to decreasing disparities between blacks and whites. The acceptability and feasibility of individualized guidelines, therefore, should be explored.

CT colonography to screen for colorectal cancer and aortic aneurysm in the Medicare population: cost-effectiveness analysis

OBJECTIVE

CT colonography (CTC) is a recommended test for colorectal cancer (CRC) screening according to the updated 2008 American Cancer Society guidelines. CTC can also accurately detect abdominal aortic aneurysm (AAA). This collaborative gastroenterology-radiology project evaluated the cost-effectiveness and clinical efficacy of CTC in the Medicare population.

MATERIALS AND METHODS

A computerized Markov model simulated the development of CRC and AAA in a hypothetical cohort of 100,000 U.S. adults > or = 65 years old. Screening with CTC at 5- and 10-year intervals using a 6-mm size threshold for polypectomy was compared with primary optical colonoscopy screening every 10 years and with no screening. Base case costs for CTC and optical colonoscopy were $674 and $795, respectively. The costs of the imaging workup for extracolonic findings at CTC were also included.

RESULTS

CTC resulted in 7,786 and 7,027 life-years gained at 5- and 10-year intervals, respectively, compared with 6,032 life-years gained with 10-year optical colonoscopy. The increase in overall efficacy with CTC was primarily due to prevention of AAA rupture because CRC prevention and CRC detection rates were similar for CTC and optical colonoscopy. All three strategies were highly cost-effective compared with no screening, with an incremental cost-effectiveness ratio (ICER) of $6,088, $1,251, and $1,104 per life-year gained for 5-year CTC, 10-year CTC, and 10-year optical colonoscopy strategies, respectively. The ICER of 5-year CTC and 10-year CTC versus optical colonoscopy was $23,234 and $2,144 per life-year gained, respectively.

CONCLUSION

Because of its ability to simultaneously screen for both CRC and AAA, CTC is a highly cost-effective and clinically efficacious screening strategy for the Medicare population.

CT colonography versus optical colonoscopy for screening asymptomatic patients for colorectal cancer a patient, intervention, comparison, outcome (PICO) analysis

RATIONALE AND OBJECTIVES

The American College of Radiology has recently endorsed the use of computed tomographic colonography (CTC) for colon cancer screening. With advances in technology and postprocessing software, the quality of computed tomographic colonographic studies has improved, and new techniques are being developed to reduce radiation exposure and increase patient acceptance of the procedure. The aim of colorectal cancer screening is to reduce the incidence of malignancy by identifying and removing presymptomatic lesions. The aim of this study was to answer the clinical question: In an asymptomatic patient at average risk for colon cancer, is CTC equivalent to optical colonoscopy (OC) for detecting clinically significant polyps?

MATERIALS AND METHODS

A systematic literature review was conducted to evaluate CTC compared to OC, using the patient, intervention, comparison intervention, outcome (PICO) search strategy. The PubMed search used Medical Subject Headings, including the terms "computed tomography colonography," "colonoscopy," "screening," and "polyp." Each of the retrieved articles was assigned a level of evidence using the Centre for Evidence-Based Medicine's hierarchy of validity for diagnostic studies.

RESULTS

PICO search criteria and review of abstracts identified 16 relevant studies. Using the Centre for Evidence-Based Medicine's hierarchy of validity, there were three level 1c studies, two level 2a studies, three level 2b studies, four level 3b studies, two level 4 studies, and two level 5 studies. All relevant studies demonstrated that CTC had high or moderately high per patient and per polyp sensitivity and specificity compared to OC for clinically relevant polyps (>5 mm).

CONCLUSIONS

The majority of evidence suggests that CTC is an acceptable alternative to OC, particularly in the group of patients who are either unwilling or unable to undergo OC. The results of the large, multicenter American College of Radiology Imaging Network study are pending. This trial presented preliminary results in 2007 suggesting that the sensitivity and specificity of CTC are high and comparable to those of OC.

Can calcium chemoprevention of adenoma recurrence substitute or serve as an adjunct for colonoscopic surveillance?

OBJECTIVES

The aim of this study was to examine the potential cost-effectiveness of calcium chemoprevention post-polypectomy as a substitute or adjunct for surveillance.

METHODS

We constructed a Markov model of post-polypectomy adenoma recurrence and colorectal cancer (CRC) development, calibrated to data from prospective chemoprevention trials of fiber, calcium, antioxidants, and aspirin. We modeled four scenarios for 50-year-old patients immediately after polypectomy: (i) natural history with no further intervention; (ii) elemental calcium 1,200 mg/day from age 50-80; (iii) surveillance colonoscopy from age 50-80 every 5 years, or 3 years for large adenoma; (iv) calcium + surveillance. Patients were followed up until age 100 or death.

RESULTS

Calcium was cost-effective compared to natural history ($49,900/life-year gained). However, surveillance was significantly more effective than calcium (18.729 versus 18.654 life-years/patient; 76 percent versus 14 percent reduction in CRC incidence) at an incremental cost of $15,900/life-year gained. Calcium + surveillance yielded a very small benefit (0.0003 incremental life-years/patient) compared with surveillance alone, at a substantial incremental cost of $3,090,000/life-year gained.

CONCLUSION

Post-polypectomy calcium chemoprevention is unlikely to be a reasonable substitute for surveillance. It may be cost-effective in patients unwilling or unable to undergo surveillance.

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

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

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

In the United States, colorectal cancer (CRC) is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. CRC largely can be prevented by the detection and removal of adenomatous polyps, and survival is significantly better when CRC is diagnosed while still localized. In 2006 to 2007, the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology came together to develop consensus guidelines for the detection of adenomatous polyps and CRC in asymptomatic average-risk adults. In this update of each organization's guidelines, screening tests are grouped into those that primarily detect cancer early and those that can detect cancer early and also can detect adenomatous polyps, thus providing a greater potential for prevention through polypectomy. When possible, clinicians should make patients aware of the full range of screening options, but at a minimum they should be prepared to offer patients a choice between a screening test that primarily is effective at early cancer detection and a screening test that is effective at both early cancer detection and cancer prevention through the detection and removal of polyps. It is the strong opinion of these 3 organizations that colon cancer prevention should be the primary goal of screening.

As tests evolve and costs of cancer care rise: reappraising stool-based screening for colorectal neoplasia

BACKGROUND

Colorectal cancer screening and treatment are rapidly evolving. Aims To reappraise stool-based colorectal cancer screening in light of changing test performance characteristics, lower test cost and increasing colorectal cancer care costs.

METHODS

Using a Markov model, we compared faecal DNA testing every 3 years, annual faecal occult blood testing or immunochemical testing, and colonoscopy every 10 years.

RESULTS

In the base case, faecal occult blood testing and faecal immunochemical testing gained life-years/person and cost less than no screening. Faecal DNA testing version 1.1 at $300 (the current PreGen Plus test) gained 5323 life-years/100 000 persons at $16 900/life-year gained and faecal DNA testing version 2 (enhanced test) gained 5795 life-years/100 000 persons at $15 700/life-year gained vs. no screening. In the base case and most sensitivity analyses, faecal occult blood testing and faecal immunochemical testing were preferred to faecal DNA testing. Faecal DNA testing version 2 cost $100 000/life-year gained vs. faecal immunochemical testing when per-cycle adherence with faecal immunochemical testing was 22%. Faecal immunochemical testing with excellent adherence was superior to colonoscopy every 10 years.

CONCLUSIONS

As novel biological therapies increase colorectal cancer treatment costs, faecal occult blood testing and faecal immunochemical testing could become cost-saving. The cost-effectiveness of faecal DNA testing compared with no screening has improved, but faecal occult blood testing and faecal immunochemical testing are preferred to faecal DNA testing when patient adherence is high. Faecal immunochemical testing may be comparable to colonoscopy every 10 years in persons adhering to yearly testing.

Projected impact of colorectal cancer screening with computerized tomographic colonography on current radiological capacity in Europe

BACKGROUND

The impact of a primary colorectal cancer screening with computerized tomographic colonography on current radiological capacity is unknown. The multispecialty needs for computerized tomographic examinations raise some doubts on the feasibility of a mass colorectal cancer screening with computerized tomographic colonography.

AIM

To assess whether the number of available computerized tomographic units in Europe is adequate to cover population screening with computerized tomographic colonography.

METHODS

A mathematical and a Markov model were, respectively, used to assess the number of computerized tomographic colonography procedures needed to be performed each day in the start-up and in the steady-state phases of a colorectal cancer screening programme in Europe. Such outcome was divided for the total number of computerized tomographic machines aged <10 years estimated to be present in the European hospitals.

RESULTS

At a simulated 30% compliance, 28 760 130 European people would need to be screened by the 3482 available computerized tomographic units in a 5-year start-up period, corresponding to 6.6 CTC/CT unit/day. Assuming a 10-year repetition of computerized tomographic colonography between 50 and 80 years, the number of computerized tomographic colonography needed to be performed in the steady-state period appeared to be 4.3/CT unit/day.

CONCLUSIONS

The current radiological capacity may cover the need for a primary colorectal cancer screening with computerized tomographic colonography in a steady state. On the other hand, a substantial implementation of the current computerized tomographic capacity or a synergistic approach with other techniques seems to be necessary for the start-up period.

Variation of agreement in polyp size measurement between computed tomographic colonography and pathology assessment: clinical implications

BACKGROUND & AIMS

Clinical management of polyps discovered by computed tomographic (CT) colonography depends on polyp size. However, size measured by CT colonography is an estimate, and its agreement with other measures is not well characterized. We hypothesized that size measurement by CT colonography varies substantially compared with measurement by other methods.

METHODS

We performed a secondary data analysis of a multicenter study of CT colonography in comparison with colonoscopy. Polyp size was determined by CT colonography, at colonoscopy, and measurement prefixation with a ruler. Agreement was assessed using descriptive statistics and Bland-Altman methodology.

RESULTS

Six hundred trial participants completed both tests. Ninety-five percent limits of agreement indicated that estimates of size by CT colonography were between 52% lower to 64% higher than prefixation polyp size estimates. Ninety-five percent limits of agreement stratified by categories of clinical importance indicated that estimates of size by CT colonography were between 44% lower to 84% higher for polyps 0.6 cm or smaller, 44% lower to 44% higher for polyps 0.6 to 0.9 cm, and 48% lower to 22% higher for polyps smaller than 0.6 cm, 44% lower to 44% higher for polyps 0.6 cm to 0.9 cm, and 48% lower to 22% higher for polyps larger than 0.9 cm compared with prefixation estimates. Analysis of participants with 1 identified polyp in the same colon segment showed that categorization based on CT colonography measurement (ie, <0.6 cm, 0.6-0.9 cm, or >0.9 cm) differed from prefixation measurement for 43% of participants.

CONCLUSIONS

Polyp size estimation by CT colonography varies from prefixation and colonoscopic measures of size. Future studies should clarify whether size estimation by CT colonography is sufficiently reliable as a primary factor to guide clinical management.

Q&A on diagnosis, screening and follow-up of colorectal neoplasia

The impressive and brisk evolution of medical science prevents many physicians from a thorough update on all the research fields. Colorectal cancer diagnosis, screening and follow-up is well known to require a multi-disciplinary approach, as it is faced by several specialties such as primary care physicians, gastroenterologists, non-gastroenterologist internists, radiologists and surgeons. To address this issue in a mutual perspective, we focused on the main points of the epidemiology, diagnosis, screening and follow-up of colorectal neoplasia by using a simple "Question & Answers" structure.

Computed tomography colonography compared with conventional colonoscopy for the detection of colorectal polyps

OBJECTIVE

To determine the diagnostic accuracy of computed tomography colonography (CTC) compared with conventional colonoscopy (CC).

METHODS

Patients with an indication of CC were included. Fifty patients underwent CTC using multidetector CT before diagnostic colonoscopy was performed by an expert colonoscopist. Diagnostic accuracy was assessed individually both for each polyp and for each patient.

RESULTS

Fifty patients were included and 40 polyps were analyzed. The by-polyp sensitivity of CTC was 15% for polyps 5 mm or less, 75% for polyps 5- 10 mm and 75% for polyps 10 mm or larger. By-patient specificity was 6% for polyps 5 mm or less, 75% for polyps 5-10 mm and 80% for polyps 10 mm or larger. The specificity of CTC was 94%. CTC was preferred over CC by 90% of the patients. The mean colonoscopy examination time was 30 minutes for CC and 35 minutes for CTC (p < 0.05).

CONCLUSIONS

The sensitivity of CTC is moderate in detecting polyps larger than 10 mm, low in detecting 5-10 mm polyps and very low in detecting those less than 5 mm. The overall specificity of the procedure was 94%. Procedure time was lower with CC than with CTC but the latter was better tolerated by most patients.